Architect's Pocket Book (Routledge Pocket Books) [6 ed.] 1032414111, 9781032414119

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Architect’s Pocket Book

This handy pocket book brings together a wealth of useful information that architects need on a daily basis – on-site or in the studio. It provides clear guidance and invaluable detail on a wide range of issues, from planning policy through environmental design to complying with Building Regulations, from structural and services matters to materials characteristics and detailing. This sixth edition includes the updating of regulations, standards and sources across a wide range of topics, with a particular focus on sustainability issues. Compact and easy to use, the Architect’s Pocket Book has sold well over 100,000 copies to the nation’s architects, architecture students, designers and construction professionals who do not have an architectural background but need to understand the basics, fast. This is the famous little blue book that you can’t afford to be without. Jonathan Hetreed and Ann Ross have drawn from decades of experience of running their own architects’ practice in Bath to update and extend the scope of this latest edition of Charlotte Baden-Powell’s Architect’s Pocket Book, reflecting continuing changes in design, construction and practice, incorporating new contributions from consultants and suppliers while retaining the compact scale and lively detail of the original. www.hetreedross.com Charlotte Baden-Powell (1936–2006)  was trained at the Architectural Association in London. She practised architecture for over 40 years, during which time she identified the need for this book, first published in 1997 and still incisively relevant today.

Architect’s Pocket Book Sixth Edition

Jonathan Hetreed and Ann Ross From the original by Charlotte Baden-Powell

Sixth edition published 2023 by Routledge 4 Park Square, Milton Park, Abingdon, Oxon OX14 4RN and by Routledge 605 Third Avenue, New York, NY 10158 Routledge is an imprint of the Taylor & Francis Group, an Informa business © 2023 Charlotte Baden-Powell, Jonathan Hetreed and Ann Ross The right of Charlotte Baden-Powell, Jonathan Hetreed and Ann Ross to be identified as authors of this work has been asserted in accordance with sections 77 and 78 of the Copyright, Designs and Patents Act 1988. All rights reserved. No part of this book may be reprinted or reproduced or utilised in any form or by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying and recording, or in any information storage or retrieval system, without permission in writing from the publishers. Trademark notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe. First edition published by Architectural Press 1997 Fifth edition published by Routledge 2017 British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloging-in-Publication Data Names: Hetreed, Jonathan, author. | Ross, Ann, 1955- author. | Baden-Powell, Charlotte, 1936Title: Architect’s pocket book / Jonathan Hetreed and Ann Ross. Description: Sixth edition. | Abingdon, Oxon: Routledge, 2023. | “From the original by Charlotte Baden-Powell.” | Includes bibliographical references and index. | Identifiers: LCCN 2022046377 (print) | LCCN 2022046378 (ebook) | ISBN 9781032414119 (paperback) | ISBN 9781032414133 (hardback) | ISBN 9781003357995 (ebook) Subjects: LCSH: Architecture—Great Britain—Handbooks, manuals, etc. Classification: LCC NA2590 .B3 2023 (print) | LCC NA2590 (ebook) | DDC 720.941—dc23/eng/20221026 LC record available at https://lccn.loc.gov/2022046377 LC ebook record available at https://lccn.loc.gov/2022046378 ISBN: 9781032414133 (hbk) ISBN: 9781032414119 (pbk) ISBN: 9781003357995 (ebk) DOI: 10.4324/9781003357995 Typeset in Frutiger by codeMantra

Contents Preface to the sixth edition ix Acknowledgements to the sixth edition xi 1 General information 1 The architect’s role in the 21st century 1 Designing for a changing climate 1 Metric system 10 Metric units 11 Temperature 12 Imperial units 13 Conversion factors 14 Greek alphabet 17 Roman numerals 17 Geometric data 18 Paper sizes 23 24 CAD (Computer Aided Design) 24 BIM (Building Information Modelling) Drawing conventions 28 32 3-Dimensional hand drawing NBS 33 33 The classifications 2 Design guidance Professional bodies for architects and technologists Planning permissions Other consents Party Wall Awards Building Regulations Dampness in buildings Construction Design and Management Regulations Standards – in the construction industry Cost estimating, contracts, fees, disputes and legal involvement for architects

35 35 36 44 50 53 61 63 67 71

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Contents

Sustainability, energy saving and green issues in a time of climate emergency 80 Landscaping 92 Anthropometric data 108 Sanitary provision for public buildings 126 3 Structures 131 Eurocodes 132 Building loading 133 Bending moments and beam formulae 144 Fire resistance 145 Low carbon design 147 Substructure (Foundations) 149 Superstructure (above ground structure) 153 Masonry structures 154 Timber construction 163 Metal structural framing systems (SFS) 175 Steel frame 176 Concrete frame 182 4 Services 187 Drainage 188 Rainwater disposal 192 Sustainable Urban Drainage Systems (SUDS) 193 Water supply regulations 196 Water storage and use 202 U-values 207 R-values 211 K-values 211 Conservation of fuel and power 212 215 Heat losses Central heating and hot water systems 219 Ventilation 224 Electrical installation 232 Lighting 237 Sound 260 Home technology integration 266

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5 Building elements 271 Enclosure 271 Stairs and balustrades 274 Fireplaces 277 Chimneys and flues 279 Doors 281 Windows 287 Pitched rooflights 294 Flat rooflights 296 Security fittings and ironmongery 299 6 Materials and components 302 Concrete 302 Brickwork and blockwork 304 Stonework 316 Damp-Proof Courses 317 Plaster and render 320 Metals 327 Insulation 330 Roofing and cladding 335 Glass 362 Glass blocks 371 Timber 373 Building boards 387 Wood-rotting fungi 401 Plastics 408 Wall and floor tiles 410 Nails and screws 411 Colour 413 Paints 415 Wallpaper coverage for walls and ceilings 419 Contacts/Sources 421 Bibliography/Sources 433 Index 435

Preface to the sixth edition In the six years since the fifth edition, the art, science and practice of architecture have continued to evolve alongside – though less dramatically than – the growing challenges of life on this planet. Accessibility of information – particularly technical information – the core of the APB’s usefulness – has grown both technically and in distribution. The sheer volume of information now available to all of us makes the positive selection and accessible presentation of it even more useful. We have aimed to enhance the relevance – especially the sustainable relevance – of material presented, thinning some of the denser sections so as to better reveal the useful core, while retaining the broad spread – and we hope the intricate ­appeal – of Charlotte Baden-Powell’s original. As ever, the scope of the book is intended to be most useful to the bespoke and smaller scale of architecture where most of our own experience has been gained. Ourselves and our many contributors – both seasoned and new – have revised, pruned and amplified individual sections, updating technical references and environmental issues in particular. Readers’ comments are gratefully received and have been taken into account in this edition. Jonathan Hetreed and Ann Ross

Acknowledgements to the sixth edition We would like to thank the following for their help and expertise in revising and updating sections of the book: Bill Gething

B  ill Gething: Sustainability + Architecture Professor of Architecture at UWE [email protected] Jonathan Reeves J onathan Reeves Vectorworks – CAD, BIM notes and diagram www.jonathanreeves-cad.co.uk Jonathan Miles Richard Dellar

J onathan C Miles, Chartered Building ­Surveyors – Party Wall guidance [email protected]  ichard Dellar Consulting Ltd – Interim CertifR icates, extension of time, dispute resolution [email protected]

Mike Andrews

Energy Saving Experts Ltd – Conservation of Fuel and Power, U-values, Lighting and Sustainability www.energy-saving-experts.com

Liz Harrison

CMLI, Liz Harrison Garden and Landscape Design – Landscaping and Plant selection www.lizharrisondesign.co.uk

Chris Gross

Integral Engineering Design – Structures www.integral-engineering.co.uk

Dr James Allen

E &M West Consulting Engineers – SUDS www.eandmwest.co.uk

 JP Consulting B Group Limited

Water regulations www.bjp-uk.com

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Acknowledgements to the sixth edition

Nigel Monaghan Lighting Design and Technology – Lighting [email protected] Jools Browning

B  rown Hen Solutions – Home Technology Integration www.brownhensolutions.com

Paul Smith

M  atrix Acoustic Design Consultants – Sound www.matrixacoustics.co.uk

We would also thank: Fran Ford

T aylor and Francis for her help in preparing the new edition.

All those who by their constructive comments on the fifth edition have helped us to make the sixth edition worth doing. Jonathan Hetreed Ann Ross

1 General information The architect’s role in the 21st century Architecture reflects the ever increasing complexity of human life and humanity’s construction solutions. One aspect of this has been the increasing specialisation of roles within design teams – though for smaller-scale projects architects often cover most of these. Whether in multi-role working or in coordination of a team of specialists, the dominant pressures in good architecture continue to be the progress of climate change and our adaptations to it: architects need above all to be aware of and appropriately responsive to these impacts on their clients and the world at large.

Designing for a changing climate Architects and their clients are necessarily at the forefront of society’s response to the two parallel challenges of climate change: Mitigation (to reduce the greenhouse gas emissions that drive change) and Adaptation (ensuring that our buildings (new and existing) are resilient to changing environmental conditions). The former remains the primary focus of ambitious statements of intent and general policy direction and has been relatively well embedded in tightening regulations, albeit that progress has not been as rapid as necessary. Progress to address the latter is less encouraging. In the words of the 2021 Climate Change Committee report to Parliament: “Climate resilience remains a second order issue, if it is considered at all. We continue to blunder into high-carbon choices.” This imbalance in responses to the twin challenges has significant implications for the industry. Whereas some design DOI: 10.4324/9781003357995-1

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strategies can address both the adaptation and mitigation agendas, some strategies targeted at one agenda can make addressing the other even more demanding. For example, our focus on reducing winter energy use by increasing insulation levels, improving air tightness and controlling winter ventilation has already profoundly changed the heat balance of our buildings and, correspondingly, the length of their heating season. Whereas the primary comfort challenge has traditionally been to keep buildings warm for the majority of the year, designers must increasingly shift their focus towards keeping them cool, whilst, of course, minimising the use of energy to do so. This applies equally to new build and retrofitting the existing stock (the primary challenge of our response to climate change). The Met Office’s UK latest Climate Projections (UKCP18-see https://www.metoffice.gov.uk/research/approach/collaboration/ukcp) provide a wealth of information on how the UK climate is likely to change. These are broadly in line with the previous projections (UKCP09) but are based on four, rather than three, scenarios for future greenhouse gas emissions. This effectively extends the range of scenarios covered by UKCP09 to include the possibility of successful mitigation of emissions towards international targets. However, it should be noted that most industry guidance and tools are still currently based on the high, medium and low emission scenarios of UKCP09. Projected changes can be summarised in general terms as: • • • •

Warmer and wetter winters Hotter and drier summers An increase in extreme events Rising sea levels

In the UK, temperatures are projected to rise more in the south than the north, and, whereas relatively little change is projected in total annual rainfall, the seasonal pattern is likely to be different, with more in winter and less in summer. The fact

General information

3

that these patterns appear to be evident in the weather patterns of recent years acts as a stark reminder of the urgency to address adaptation and resilience (see Met Office mapping on the following pages). In similarly general terms, impacts on the built environment can be considered under three headings: • Comfort and energy use – particularly in increasing the likelihood of overheating • Construction – changes in the behaviour of materials, impacts on detailing to deal with increased storminess and foundation design on shrinkable soils • Water – too little (the impact of changing rainfall patterns on water supply) and too much (flooding from a variety of sources) Note that impacts will vary geographically, both in terms of broad regional differences and the specific circumstances of a particular location. Overheating, for example may be more of an issue in warmer regions and particularly in urban areas subject to the heat island effect, whereas flooding may be a key design driver for sites close to rivers or beside the sea but less of a concern inland on higher ground – although surface water flooding can affect any location. Given the uncertainty about the speed and ultimate extent of climate change, it is important to note that there is no such thing as a “climate proof” building. What is needed is an adaptation strategy to enable a building to accommodate an agreed level of change and incorporating further measures to increase its resilience if necessary through its life; ideally aligned with maintenance and replacement cycles. The Probabilistic Climate Profiles (ProCliP), available free of charge from CIBSE (https://www.cibse.org/knowledge-research/ knowledge-portal/probabilistic-climate-profiles-the-­effectiveuse-of-climate-projections-in-building-design-2014-pdf), provide a useful way of visualising the range of change over the next 80 years and how the different emissions scenarios relate

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to each other. They cover the following building relevant environmental variables: • • • •

Seasonal mean air temperature Daily minimum winter temperatures Daily maximum summer temperatures Seasonal daily precipitation

These are available for 14 UK locations and can help designers and their clients select appropriate future climate design parameters for their project. Summertime comfort is a key concern, as noted above, with the growing realisation that overheating is very much a current as well as a future issue, particularly for new homes. The Good Homes Alliance guide: Overheating in New Homes provides useful guidance and rules of thumb to inform early-stage design (https://goodhomes.org.uk/overheating-in-new-homes). However, overheating in homes is now covered by a new Building Regulation (Part O). This has two options: a “simplified method” requiring measurements of glazed areas, ventilation openings, floor areas, orientation, etc. and the use of a slightly modified version of CIBSE’s TM59 (Design methodology for the assessment of overheating risk in homes) requiring the use of full dynamic simulation. This specifically takes climate change into account, rather than relying on inherently out-of-date historic weather averages, requiring the use of “future” weather data: a Design Summer Year for an averagely warm year (DSY1) for the 2020s based on the 50th percentile high emissions scenario. In addition, it recommends testing designs against more extreme weather files: DSY2 (a year with a very intense single warm spell (like 2003)) and DSY3 (a year with a prolonged period of sustained warmth (like 1976) and later years. The GLA similarly requires designs to be tested against these future weather files and individual local authorities may suggest specific weather files representative of potential conditions further into the century. For example, the London Borough of Islington requires evidence of a future adaptation strategy to cope with conditions represented by a 2050 90th percentile medium emissions DSY.

General information

5

The use of specific future weather files is a significant step forward from a situation where there was no consensus on what were “reasonable” parameters when designing for future climate. It was up to the client and design team for each individual project to try to agree what parameters to adopt. Suitable future weather files are available from CIBSE for 14 locations (https://www.cibse.org/weatherdata) and (free of charge) for 45 locations from the PROMETHEUS project lead by the University of Exeter (http://emps.exeter.ac.uk/engineering/ research/cee/research/prometheus/downloads/). Architects design buildings that respond to a set of contexts: physical, cultural, social, economic and environmental. There is no doubt that the profession faces huge challenges in meeting and anticipating unprecedented changes in those contexts. However, with those challenges come corresponding opportunities to enhance the environmental performance of new and existing buildings and reduce their energy bills whilst continuing to exceed their clients’ expectations both in terms of function and delight. The UK’s climate has continued to warm, with 2020 the first year to have temperature, rain and sunshine rankings all in the top 10. The latest analysis of the UK climate, State of the UK Climate 2020 published in The Royal Meteorological Society’s International Journal of Climatology, has shown that climate change is already being felt across the UK. All of the top-ten warmest years for the UK in records back to 1884 have occurred since 2002, and, for central England, the 21st century so far has been warmer than the previous three centuries. The last 30-year period (1991–2020) has been 0.9°C warmer than the preceding 30 years (1961–1990). The warming trend is evident across all months and all countries in the UK. The greatest warming compared to 1961–1990 has been across the east Midlands and East Anglia where average annual temperatures have increased by more than 1°C, with the least warming around western coastal fringes and parts of Northern Ireland and Scotland.

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© Crown copyright, Met Office © British Crown copyright, Met Office

General information

7

As well as increased temperatures, the UK has been on average 6% wetter over the last 30 years (1991–2020) than the preceding 30 years (1961–1990). Six of the ten wettest years for the UK in a series from 1862 have occurred since 1998. The year 2020 was the first in which the annual values for rainfall, temperature and sunshine were all in the top ten in the same year. It was the third warmest, fifth wettest and eighth sunniest on record for the UK.

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www.metoffice.gov.uk © Crown copyright, Met Office © British Crown copyright, Met Office.

General information

Sea areas, inland areas and coastal stations Used in weather forecasts by the Met Office

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Metric system The Système International d’Unités (SI), adopted in 1960, is an international and coherent system devised to meet all known needs for measurement in science and technology. It consists of seven base units and the derived units formed as products or quotients of various powers of the base units. SI Base units metre kilogram second ampere kelvin candela mole

SI Prefixes (showing the twelve most common)

M Kg S A K

length mass time electric current thermodynamic temperature Cd luminous intensity mol amount of substance

1 000 000 000 000 1012 1 000 000 000 109 1 000 000 10 6 1000 103 100 102

tera giga mega kilo hecto

T G M K H

deca

Da × 10 101

deci

D

÷ 10 10 –1

centi milli micro nano pico

C M μ N P

÷ ÷ ÷ ÷ ÷

× × × × ×

100 10 –2 1000 10 –3 1 000 000 10 –6 1 000 000 000 10 –9 1 000 000 000 000 10 –12

SI Derived units celsius coulomb farad henry hertz joule lumen lux newton ohm pascal siemens tesla volt watt weber

ºC C F H Hz J lm lx N Ω Pa S T V W Wb

= = = = = = = = = = = = = = = =

K As C/V W/A c/s Ws cd.sr lm/m2 kg/m/s2 V/A N/m2 1/W Wb/m2 W/A J/s Vs

temperature electric charge electric capacitance inductance frequency energy luminous flux illuminance force electric resistance pressure electric conductance magnetic flux density electric potential power magnetic flux

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SI Supplementary units radian

rad

=

steradian

sr

=

unit of plane angle equal to an angle at the centre of a circle, the arc of which is equal in length to the radius unit of solid angle equal to an angle at the centre of a sphere subtended by a part of the surface equal in area to the square of the radius

Metric units Length kilometre metre

km m

= =

decimetre centimetre millimetre micron

dm cm mm μ

= = = =

1000 metres length of path travelled by light in vacuum during a time interval of 1/299 792 458 of a second 110 metre 1/100 metre 1/1000 metre 1/100 000 metre

Area hectare area

ha a

10,000 m2 100 m2

= =

Volume m3 mm3

cubic metre cubic millimetre

= =

m×m×m 1/1 000 000 000 m3

Capacity hectolitre litre decilitre centilitre millilitre

hl l dl cl ml

= = = = =

100 litres cubic decimetre 1/10 litre 1/100 litre 1/1000 litre

= = = =

1000 kilograms 1000 gram 1/1000 kilogram 1/1000 gram

Mass or weight tonne kilogram gram milligram

t kg g mg

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Temperature Kelvin (K) The kelvin belongs to a group of seven SI base units used as a quantitative unit of thermodynamic temperature. It is named after Lord William Thompson Kelvin, a Scottish physicist (1824–1907). In 1848, he suggested a scale of temperature, now called kelvin, in which the zero point is absolute zero – the temperature at which the motions of particles cease and their energies become zero. The units of kelvin and degree Celsius temperature intervals are identical (thus 1ºC = 1 K), but the point of absolute zero in Celsius is minus 273.15ºC, thus 0ºC = 273.15 K. It is now customary for temperature and temperature intervals to be described in degrees Celsius (ºC) although colour temperature of light sources is measured in degrees Kelvin (K). Celsius (ºC) The Celsius scale is a scale of temperature on which water freezes at 0º and boils at 100º under standard conditions. It was devised by Anders Celsius, a Swedish astronomer (1701–1744). He originally designated zero as the boiling point of water and 100º as freezing point. The scale was later reversed. Centigrade A temperature scale using the freezing point of water as zero and the boiling point of water as 100º. The scale is now officially called Celsius (see above) to avoid confusion in Europe where the word can mean a measure of plane angle and equals 1/10 000 part of a right angle. Fahrenheit (ºF) A scale of temperature still used in the US which gives the freezing point of water as 32º and boiling point as 212º. Named after Gabriel Daniel Fahrenheit, a Prussian physicist (1686–1736) who invented the mercurial barometer. The Fahrenheit scale is related to the Celsius scale by the following relationships: temperature ºF = (temperature ºC × 1.8) + 32 temperature ºC = (temperature ºF − 32) ÷ 1.8

General information

Imperial units Length mile furlong chain yard (yd) foot (ft) inch (in)

= = = = = =

1760 yards 220 yards 22 yards 3 feet 12 inches 1/12 foot

= = = = = =

640 acres 4840 square yards 1210 square yards 9 square feet 144 square inches 1/144 square foot

= = =

27 cubic feet 1/27 cubic yard 1/1728 cubic foot

= = = = = = = = = =

2240 pounds 112 pounds 100 pounds 28 pounds 14 pounds 16 ounces 1/16 pound 1/16 ounce 1/7000 pound 24 grains

Area square mile acre rood square yard (sq yd) square foot (sq ft) square inch (sq in)

Volume cubic yard cubic foot cubic inch

Weight tonne hundredweight (cwt) cental quarter stone pound (lb) ounce (oz) dram (dr) grain (gr) pennyweight (dwt)

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Conversion factors Imperial to SI Length

Area

1.609 0.9144 0.3048 25.4 2.590 0.4047 0.8361 0.0929 645.16

SI to Imperial Mile Yard Foot Inch

Kilometre Metre Metre Millimetre

km m m mm

0.6215 1.094 3.281 0.0394

Sq mile Acre Sq yard Sq foot Sq inch

Sq kilometre Hectare Sq metre Sq metre Sq millimetre

km2 ha m2 m2 mm2

0.3861 2.471 1.196 10.7639 0.00155

Volume

0.7646 0.02832 16.39

Cubic yard Cubic foot Cubic inch

Cubic metre m3 Cubic metre m3 Cubic millimetre mm3

1.3079 35.31 0.000061

Capacity

28.32 0.01639 16.39 4.546 28.4125

Cubic foot Cubic inch Cubic inch UK gallon Fluid ounce

Litre Litre Millilitre Litre Millilitre

l l ml l ml

0.03531 61.0128 0.06102 0.21998 0.0352

Tonne Pound Pound Ounce

Tonne Kilogram Gram Gram

t kg g g

0.98425 2.20458 0.002205 0.03527

Kilogram/m3

kg/m3

0.06243

Mass

1.016 0.4536 453.6 28.35

Density

16.0185

Pound/ft3

Force

4.4482 14.59

Pound force Newton Pound f/foot Newton/metre

N N/m

0.22481 0.06854

Pressure, stress 4.882 107.252 47.8803 6894.76

Pound/ft2 Tonne f/ft2 Pound f/ft2 Pound f/in2

kg/m2 kN/m2 N/m2 N/m2

0.2048 0.009324 0.02088 0.000145

Energy

Kilowatt hour Megajoule

MJ

0.27777

Btu

J

0.000948

Heat

3.6 1055.0

Kilogram/m2 Kilonewton/m2 Newton/m2 Newton/m2

Joule

General information

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Heat flow 0.000293 Btu/h

Kilowatt

kW

Watt/m2 ºC

W/m2 ºC

0.17611

Thermal conductivity 0.144228 Btu in/ft2h ºF Watt/m ºC

W/m ºC

6.93347

Cost

£/m2

Heat transfer 5.67826

0.0929

Btu/ft2h ºF

£/sq foot

£/sq metre

Approximate metric/Imperial equivalents Length 1.5 mm 3 mm 6 mm 12.5 mm 19 mm 25 mm 100 mm 600 mm 2000 mm 3000 mm

= = = = = = = = = =

1

/16″ / 8″ ¼″ ½″ ¾″ 1″ 4″ 2′0″ 6′8″ 10′0″

1

Temperature ºC 100 37 21 19 10 0 −17.7

= = = = = = =

F 212 98.6 70 66 50 32 0

Heat transfer 1 Btu/ft2hºF

=

10 watt/m2 ºC

boiling blood heat living room bedroom freezing

3415.0

10.7639

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Lighting 10 lux

=

1 lumen/ft2

= =

2½ acres 1 acre

= = = =

2¼ lbs 1 ounce 3½ ounces 1 lb

= =

1¾ pints 2 gallons

= = = =

30 lbs/ft2 50 lbs/ft2 70 bs/ft2 100 lbs/ft2

Area 1 hectare 0.4 hectare

Weight 1 kilogram 28 grams 100 grams 454 grams

Capacity 1 litre 9 litres

Pressure 1.5 kN/m2 2.5 kN/m2 3.5 kN/m2 5.0 kN/m2

Glass thickness 2 mm 3 mm 4 mm 6 mm

= = = =

18 oz 24 oz 32 oz ¼″

General information

Greek alphabet Capital

Lower case

Name

English transliteration

A B G D E Z H Q I K Λ M N X O Π R Σ T γ Φ X ψ Ω

a  g d e z h q i k l m n c o p r s (V)* t u f χ c w

alpha beta gamma delta epsilon zeta eta theta iota kappa lambda mu nu xi omicron pi rho sigma tau upsilon phi chi psi omega

a b g d e z e– th i k l m n x o p r s t u ph ch, kh ps o–

*

ς at end of word

Roman numerals I = one V = five X = ten L = fifty

C = one hundred D = five hundred M = one thousand

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Geometric data Measurement of plane and solid figures π (pi)

=

3.1416

= =

π × diameter π × ½ major axis + ½ minor axis

circle cone

= =

cylinder ellipse parabola parallelogram pyramid

= = = = =

sector of circle segment of circle sphere triangle triangle (equilateral)

= = = =

π × radius2, or 0.7854 × diameter2 ½ circumference × slant height + area of base circumference × length + area of two ends Product of axes × 0.7854 (approx) base ×2 / 3 height base × height ½ sum of base perimeters × slant height × area of base (π× degrees arc × radius2) ÷ 360 area of sector minus triangle π × diameter2 ½ base × perpendicular height

=

(Side)2 × 0.433

= = = = =

area of base ×1/ 3 perpendicular height π × radius2 × height area of base ×1/ 3 height diameter3 × 0.5236 area of base × ½ perpendicular height

Circumference circle cone

Surface area

Volume cone cylinder pyramid sphere wedge

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Nine regular solids Various types of polyhedra have exercised the minds of mathematicians throughout the ages, including Euclid, whose great work The Elements was intended not so much as a geometry text book but as an introduction to the five regular solids known to the ancient world. This work starts with the equilateral triangle and ends with the construction of the icosahedron. The five so-called Platonic solids form the first and simplest group of polyhedra. They have regular faces, all of which touch one another, and the lines that make up any of the vertices form a regular polygon. Further variations of the regular polyhedra, unknown in ancient times, are the Kepler-Poinsot star polyhedra. In all four cases the vertex figures spring from pentagrams. These polyhedra can be formed from the regular dodecahedron and icosahedron. Kepler (1571–1630) found the two stellated dodecahedra, and Poinsot (1777–1859) discovered the great dodecahedra and the great icosahedron.

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Five Platonic solids

The Kepler–Poinsot star polyhedra

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Golden section The golden section or golden mean is an irrational proportion probably known to the ancient Greeks and thought to be divine by Renaissance theorists. It is defined as a line cut in such a way that the smaller section is to the greater as the greater is to the whole, thus: AC: CB = CB: AB

The ratio of the two lengths is called phi F. Φ=

5 +1 = 1.61803... 2

For approximate purposes, it is 1 : 1.6 or 5 : 8. F is the ratio of line lengths in any pentagram.

The golden rectangle is one in which F is the ratio of one side to the other. This is implicated in the mathematics of growth as demonstrated in the Fibonacci series 0, 1, 1, 2, 3, 5, 8, 13, 21, 34… where each number is the sum of the preceding two. This ratio of successive numbers increasingly approaches that of the golden rectangle.

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The Fibonacci spiral is a curve that increases constantly in size without changing its basic shape. This is demonstrated by using squares increasing in the Fibonacci scale, that is, 1, 2, 3, 5, from the diagram of which can be seen three nearly golden rectangles. Leonardo Fibonacci (c.1170–1230) was an Italian mathematician who introduced Arabic numerals to Christian Europe. He travelled extensively, particularly in North Africa where he learnt the decimal system and the use of zero. He published this system in Europe but mathematicians were slow to adopt it. Le Corbusier used the Fibonacci series in his system of proportion ‘Le Modulor.’ To draw a golden rectangle: Draw a square ABCD. Halve the base line at E. From this point draw a line to corner C and with radius EC drop an arc to find point F. The golden rectangle is AFGD as also is BFGC. The angle between the diagonal and the long side of a golden rectangle is approximately 31.45º.

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Paper sizes International paper sizes The basis of the international series is a rectangle having an area of one square metre (A0), the sides of which are in the proportion of 1:√2. This is the proportion of the side and diagonal of any square. All the A series are of this proportion, enabling them to be doubled or halved and remain in the same proportion, which is useful for photographic enlargement or reduction. A0 is twice A1 which is twice A2 and so on. Where larger sizes than A0 are needed the A is preceded by a figure, thus 4A is four times A0. The B series are sizes intermediate between any two A sizes. This series is used mostly for posters and charts. The C series are envelopes to suit the A sizes. DL or long sizes are obtained by dividing the A and B series into three, four or eight equal parts parallel to the shorter side so that the proportion of 1:√2 is not maintained. In practice, the long sizes should be produced from the A series only. Paper sizes- 'A' series

1189 594 297 148 74

841 420 210 105 52

The ratio of the sides = 1:1.4142

A1

A0

A3

A2

A5 A7

A4 A6

A8

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CAD (Computer Aided Design) Most drawings are now produced on computers enabling instant transfer of information between architects, clients and consultants. There are many computer aided design (CAD) systems available and the most commonly used programs are AutoCAD, Vectorworks, Archicad and MicroStation and depending on the scale and complexity of projects. Drawings should be constructed in layers organising the project into different building elements, locations or materials. Most architectural CAD software can also be used for 3D modelling, which can be useful in terms of design development and communication of ideas. These functions are often complemented by external applications such as SketchUp, Cinema 4D, 3DS Studio Max and V-RAY, with further graphic enhancement provided by using image editing software like Photoshop. Standard protocols apply for drawing methods and notation and many manufacturers now supply technical information in CAD format for downloading as DWG, DXF or PDF. 3D PDF is also now a common format for sending and viewing 3D files in a readable format that anyone can view and comment on without the use of specialist software.

BIM (Building Information Modelling) Building Information Modelling (BIM) is also now an essential part of the architectural design process, and construction process. Design-led BIM involves constructing an accurate 3D computer model of the proposed building, which allows elevations, sections and 3D visuals to be extracted from the model rather than drawn, allowing design options to be explored more accurately. Most BIM software systems use parametric objects such as spaces, walls, slabs, roofs, columns, and doors and windows to represent the building design. The user

General information

25

can then customise the parametric tools to the required type, along with inputting information such as materials, quantities, costs or “u” values to be assigned allowing the user to interrogate different design options more efficiently. Collaborative BIM workflows involve sharing the BIM model with other consultants, clients or other stakeholders such as facilities managers. The most common file format for BIM model exchange is known as Industry Foundation Classes or (IFC). IFC files can contain both embedded information as well as the three-dimensional (3D) geometrical description of the objects. Model viewing software such as Solibri, Navisworks and Tekla BIMsight, can be used to import IFC files from consultants, automatically check for clashes, create schedules and communicate with others. The UK government helped drive the adoption of BIM in the construction industry by mandating that publicly funded projects should use BIM Level 2 workflows by 2016. BIM Level 3 is envisaged as the next stage in development, and the UK government has been aiming for implementation in the mid-2020s. One of the main requirements for BIM Level 3 is the availability (and implementation) of an international set of standards. In other words, there should be a set of ISO standards that regulate BIM processes and procedures. This will enable the interconnected digital design of different elements in a built environment and will extend BIM into the operation of assets over their lifetimes – where the lion’s share of cost arises. It will support the accelerated delivery of smart cities, services and grids.

Real-time rendering Real-time rendering is a field of computer graphics focused on analysing and producing images in real time. Over the

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last few years, rapid developments in computer graphics processing (GPU) combined with developments in software which emerged from the gaming industry have started to revolutionise the way architects develop designs. The benefit of real-time rendering is that users can now interact with the rendered worlds as they are developed. Users can change time, weather and location, as well as adding animated people, trees and props to create very convincing virtual environments. Software like Unreal Engine, Twinmotion, Enscape and Lumion now makes it easy for designers to visualise their 3D and BIM models in unique and compelling ways using affordable virtual reality headsets and cloud-sharing capabilities.

Virtual reality, cloud computing and the Metaverse Virtual Worlds are 3D immersive environments accessed through a computer. They are intended for use beyond pure entertainment and are often powered by cloud computing. The Metaverse is a futuristic vision of an interconnected virtual world characterised by persistent virtual worlds that continue to exist even when you’re not present. This includes some sort of new digital economy, where users can create, buy and sell goods and experience augmented reality that combines aspects of the digital and physical worlds. There is currently a lot of interest in architects and designers being actively involved in developing the virtual environments of the Metaverse. The designers at the forefront of this digital revolution will have an important role to play with creative input to make the most of these new virtual worlds. Many of the CAD/BIM drawings in this book have been drawn using Vectorworks Architect.

General information

www.jonathanreeves-cad.co.uk www.real-time-rendering.com

27

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Drawing conventions Demolition

existing wall

wall to be demolished

removal of part

infilling opening

removal of area

making good after forming opening

9

8

7

6

5

4

3

2

1

Steps, ramps, slopes and flow

10

11

12

13

16

17

18

stair or ramp (direction of rise)

dogleg staircase (arrow points up)

natural drainage (direction of fall)

flow (direction of watercourse)

2.350

2.150

slope (direction of fall)

ramp (arrow points up)

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29

Landscape contour - existing

gate

contour - proposed

fence

line of no cut / no fill

hedge - existing

hedge - proposed cut volume (in section)

tree - to be removed fall of ground (arrow point down)

bank (arrows point down)

tree - existing

cutting (arrows point down)

tree - proposed

grass

x

planting bed

tree - protection (of existing)

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Masonry

brickwork

blockwork

lightweight block

stonework

engineering brick

brickwork running bond

stonework running bond

stonework random rubble

blocking (any type)

softwood machined all round

hardwood machined all round

Timber

rough sawn (any type)

Site-formed materials

concrete

plaster / render screed

granular fill

asphalt macadam

mulch

topsoil

subsoil

hard fill

sheet - large scale

plywood

glass sheet

insulation quilt

insulation board

Manufactured materials membrane board layer sheet - small scale

blockboard

veneered blockboard

General information

Doors

31

Windows hinged leaf

hinged leaf (alternative) hinged leaf normally closed (reverse if normally open) hinged leaf opening 180 o

F

hinged leaf side hung casement (arrow points to hinge - reverse on european windows) top hung casement

bottom hung casement

horizontal pivot hinged leaf opening both ways

bi-parting pair of hinged leaves

sliding leaf

vertical pivot

vertical pivot reversible horizontal hinge projecting out (H window)

horizontal sliding revolving leaves vertical sliding sliding folding leaves end-hung

slide and tilt

sliding folding leaves centre-hung

tilt and turn

Source: BS EN ISO 19650

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ISO 19650 is a series of international standards. It defines the collaborative processes for the effective management of information throughout the delivery and operational phase of assets when building information modelling (BIM) is being used. www.bsigroup.com

3-Dimensional hand drawing Although most perspective images in architectural practice are now produced using 3D modelling via CAD programmes, or by free-hand sketching, the methodology for perspective drawing may be useful on occasion and many methods can be found online: Perspective drawing – method of setting up

General information

33

NBS www.thenbs.com NBS is an integrated global platform for everyone involved in the design, supply and construction of the built environment. NBS Chorus is a cloud-based specification writing platform for the construction industry. It includes libraries of pre-­ written specification clauses, guidance and manufacturer product information authored by a multi-disciplinary specialist team. NBS Source is a powerful, intuitive search enabling the user to easily find the products and manufacturers that are right for their projects. Uniclass is a dynamic and unified classification system for the construction industry covering all sectors, maintained and updated by NBS.

The classifications • CI/SfB is the classification system most widely used by architectural specifiers. The system has been in operation for more than 30 years and is the industry standard. • Uniclass is a UK classification system for structuring product literature and project information, incorporating both Common Arrangement of Work Sections (CAWS) and EPIC.

CI/SfB Construction index CI/SfB is a library system used by the building industry and is suitable for the smallest or largest office. CI SfB

= =

Construction Index Samarbetskommitten för Byggnadsfrägor – a Swedish system of the late 1940s

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CI/SfB notation has four divisions: Table 0 Table 1 Tables 2 and 3 Table 4

= = = =

0

1

2&3

4

Physical environment Elements Constructions and materials Activities and requirements

The current CI/SfB edition was issued in 1976 and is still widely used. It was reviewed and the Uniclass system was developed as a result of this.

Uniclass Uniclass is a unified classification system for the built environment covering all sectors and roles, delivered by NBS. Uniclass is a way to organise everything required for built environment assets and provide a logical code for each general item, which can be used by anyone to identify and refer to it. Uniclass uses a set of tables to group similar things together, arrange them consistently and make searching easy. The tables are ordered as a hierarchy (imagine a ladder or pyramid) that helps users classify at all scales, from very large things like a hotel complex or road network to small products like staples or clay bricks, and everything in between. In addition, there are also tables to support information management processes, project management and communication. The name Uniclass expresses that it is a unified classification, suitable for everyone involved in the built environment, where the whole lifecycle of buildings, landscape features and infrastructure assets can all be classified using its consistent approach, and with the scope to expand for any future industry needs. https://www.thenbs.com/knowledge/what-is-uniclass

2 Design guidance Professional bodies for architects and technologists Architects Registration Board – ARB www.arb.org.uk ARB is an independent professional regulator, established by Parliament as a statutory body, through the Architects Act, in 1997. We are accountable to the government. The law gives us a number of core functions: • To ensure only those who are suitably competent are allowed to practise as architects. We do this by approving the architecture qualifications required to join the Register of architects. • We maintain a publicly available Register of architects so anyone using the services of an architect can be confident that they are suitably qualified and are fit to practise. • We set the standards of conduct and practice the profession must meet and take action when any architect falls below the required standards of conduct or competence. • We protect the legally restricted title ‘architect.’

Royal Institute of British Architects – RIBA www.architecture.com The Royal Institute of British Architects is a global professional membership body driving excellence in architecture. We serve our members and society in order to deliver better buildings and places, stronger communities and a sustainable environment. DOI: 10.4324/9781003357995-2

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Being inclusive, ethical, environmentally aware and collaborative underpins all that we do. The RIBA was founded in 1834 for ‘the general advancement of Architecture, and for promoting and facilitating the acquirement of the knowledge of the various arts and sciences connected therewith.’

Royal Incorporation of Architects in Scotland – RIAS www.rias.org.uk The Royal Incorporation of Architects in Scotland (RIAS) was founded in 1916 as the professional body for all chartered architects in Scotland and is the foremost Institute in the country dealing with architecture and the built environment. The RIAS has charitable status and offers a wide range of services and products for architects, students of architecture, construction industry professionals and all those with an interest in the built environment and the design process.

Chartered Institute of Architectural Technologists – CIAT www.architecturaltechnology.com CIAT is a dynamic, forward-thinking and inclusive global membership qualifying body for Architectural Technology. It represents those practicing and studying within the discipline and profession.

Planning permissions Definitions Original House

The house as it was first built, or as it stood on 1 July 1948 if it was built before that date. House does not include flats.

Highway

All public roads, footpaths, bridleways and byways, adopted or unadopted.

Article 2(3) Land

Land within a Conservation Area, National Park, Area of Outstanding Natural Beauty and the Broads, or World Heritage Site.

Cubic Content

The cubic content of a structure or building measured externally.

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Summary of planning permissions Under the UK Town and County Planning system, planning permission is required for all development; development means the carrying out of building, engineering, mining or other operations in, on, over or under land, or the making of any material change in the use of any buildings or other land. The carrying out of maintenance, for improvement or other alteration of any building that affects only the interior of the building, or that does not materially affect the external appearance of the building, is not development. In many cases, an application will be required to the Local Planning Authority for planning permission, although many types of development are granted a general planning permission and are considered to be ‘permitted development’ subject to compliance with specific conditions, and in some cases subject to a prior approval or notification procedure with the Local Planning Authority or adjoining owners/occupiers. Where a planning application is required, it is possible (and encouraged) to discuss proposals with the Local Planning Authority in advance of making a formal application. A variety of different protocols exist for this in different locations. Where development may be ‘permitted development’ (and therefore does not require an application for planning permission), it may be possible to obtain informal confirmation of this from a Local Planning Authority; alternatively, formal confirmation can be obtained by the submission of an application for a Lawful Development Certificate. Informal advice from planning officers is less readily available than it used to be, though formalised ‘pre-application advice’ can usually be obtained on the basis of preliminary information at low risk for clients. The planning portal website offers useful advice on the extent of ‘permitted development’ – that is, that permitted without planning consent. Source: www.planningportal.co.uk Planning permission (by application to the Local Planning Authority) is generally needed for the following work to houses

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and flats in England. Different rules apply in Wales, Scotland and Northern Ireland. 1. Dividing off part of a house for use as a separate dwelling. 2. Use of a caravan in a garden as a home. 3. Dividing off part of a house for business or commercial purposes. 4. Providing a parking place for a commercial vehicle or taxi. 5. Building something that goes against the terms of any planning permission, including alterations or additions to a dwelling created via permitted development. 6. Work that will involve a new or altered access to a trunk or classified road or ‘highway.’ 7. External alterations, additions or extensions to a flat or maisonette, including those converted from houses, excluding internal alterations that do not affect the external appearance (Listed Building Consent could be required for internal alterations to flats or houses). House extensions 8. Covering more than half the area of land around the original house with additions or other separate buildings including outbuildings. 9. Where the height of the altered house would be higher than the highest part of the roof of the original house. (Class AA which was inserted in 2021 allows for the enlargement of a dwellinghouse by construction of up to two additional storeys, various detailed conditions apply and this provision is subject to an application for Prior Approval to the LPA.) 10. Where the height of the eaves of the altered house would be higher than the eaves of the existing house. Separate rules apply to houses with different height eaves, on slopes or with flat roofs. 11. If the enlarged part of the house is closer to a highway than a wall which fronts the highway and forms the principal or side elevation of the original house. There are exceptions where the distance to the highway is ‘substantial.’

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12. If a single storey extension extends beyond the rear wall of the house by more than 8 m for a detached house and more than 6 m for any other house (see the section on Other Consents). 13. Where the enlarged part of the house has more than one storey and extends beyond the rear wall of the house by more than 3 m. 14. If the enlarged part of the house has more than one storey and is less than 7 m from any curtilage boundary opposite the rear wall of the house. 15. Where the enlarged part of the house is within 2 m of the boundary of the curtilage of the house and the height of the eaves of the enlarged part exceeds 3 m. 16. If the enlarged part of the house extends beyond the side elevation of the house, exceeds 4 m in height or has more than one storey or is greater in width than half the width of the original house. For extensions which affect both the side and rear wall, both sets of restrictions apply. 17. Any total enlargement (being the enlarged part together with any existing enlargement of the original dwellinghouse to which it will be joined) exceeds or would exceed the limits set out above. Porches: 18. Where the ground area of the porch structure exceeds 3 m2. 19. Where any part of the porch structure is more than 3 m above ground level. 20. Where any part of the porch structure is within 2 m of an adjoining highway boundary. House extensions Note: Where the house is on Article 2(3) Land the following will always require planning permission: a b c

Cladding any part of the exterior. Enlarging the house beyond the side elevation of the original. Enlarging the house by more than one storey beyond the original rear wall.

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For roof extensions, planning permission will be required 21. Where the house is in Article 2(3) Land. 22. Where the height of the altered house would be higher than the highest part of the roof of the original house. (Class AA which was inserted in 2021 allows for the enlargement of a dwellinghouse by construction of up to two additional storeys, various detailed conditions apply and this provision is subject to an application for Prior Approval to the LPA.) 23. Where any part of the extension would extend beyond the plane of any existing roof slope on the principal elevation fronting a highway. 24. Where the resulting roof space exceeds the cubic content of the original roof space by 40 m3 for a terraced house or 50 m3 elsewhere. 25. Other alterations are permitted to enable the installation of rooflights without planning permission but conditions apply. For Permitted Development Extension Schemes including roof extensions, the following conditions apply. If these are not met it may be necessary to apply for planning permission 26. The materials used must be of similar appearance to those used for the exterior of the existing house except for conservatories. 27. Upper floor windows or rooflights in a wall or roof slope forming a side elevation must be obscured glazing. 28. Upper floor windows can only contain opening parts where they are more than 1.7 m above the floor of the relevant room. 29. Where the enlarged part of the house is more than one storey the roof pitch should, as far as practicable, be the same as the original house. 30. The closest edge of the eaves of a roof extension should be not less than 20 cm from the eaves of the original roof.

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Under some circumstances the following may require planning permission: 31. The construction of a veranda, balcony or raised platform. 32. The installation, replacement or alteration of a microwave antenna. 33. The installation, alteration or replacement of a chimney, flue or soil pipe. Separate new buildings on the land around the house will require planning permission where 34. Any building, enclosure or container is to be used other than for domestic purposes or which exceeds condition nine above. 35. Any building, enclosure or container would be on land in front of the principal elevation of the house. 36. Any building, enclosure or container would be more than a single storey. 37. Any building, enclosure or container would be within 2 m of the boundary which is more than 2.5 m high. 38. Any building, enclosure or container more than 4 m high with a dual pitched roof or 3 m high in any other case. 39. Any building, enclosure or container where the eaves height exceeds 2.5 m. 40. Any building, enclosure, pool or container in the grounds of a Listed Building. 41. Any container with a capacity greater than 3500 litres. 42. In National Parks, Areas of Outstanding Natural Beauty, the Norfolk and Suffolk Broads or World Heritage Sites any building enclosure or container in excess of 10 m2 if situated more than 20 m from any wall of the house. Erecting fences, walls and gates require permission 43. If a house is a Listed Building. 44. If over 1 m high where next to a road or over 2 m elsewhere. Chimneys, flues, soil and vent pipes Apart from on Article 2(3) Land these are permitted unless they exceed the highest part of the roof by 1 m or more.

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Planting hedges or trees 45. If a condition was attached to the planning permission of the property that restricts such planting. Erecting a satellite dish or antenna Other than normal TV or radio aerials. There is a general permission to install antenna up to a specific size on property without the need for planning permission but there are conditions that apply and should be checked. Driveways 46. If a new or wider access is made onto an adopted road. Approval of the highways department of the local council will also be needed if a new driveway crosses a pavement or verge. Energy Infrastructure Part 14 of the General Permitted Development Order relates to renewable energy and grants a variety of permitted development rights for new microgeneration and EV charging infrastructure, including solar PV, solar thermal, air source heat, and wind turbines on domestic and non-domestic buildings and premises. There are various detailed restrictions and conditions which should be reviewed on a case-by-case basis when installing or modifying renewable energy infrastructure. Planning permission is not required for Sheds, garages, greenhouses, domestic pet houses, summer houses, swimming pools, ponds, sauna cabins or tennis courts, unless they contravene the conditions described above, the relevant details of any project, and the need for an application to the Local Planning Authority, should be checked. Creation or replacement of patios, hard standings, paths and driveways unless used for parking a commercial vehicle or taxi.

Design guidance

43

If in front of the principal elevation or exceeding 5 m2, however, the hard surface must direct water to a permeable or porous area within the curtilage. Normal domestic TV and radio aerials – but see under Erecting a satellite dish or antenna, above. Repairs, maintenance or minor improvements such as redecorating or replacing windows, insertion of windows, skylights or rooflights but see the next section on Listed Buildings and Conservation Areas, where consents may be needed. Planning Permission may not be required for some changes of use to create new dwellings, including the conversion of agricultural buildings and some other commercial buildings to residential use. Where such development is proposed limited external alterations are allowed although alterations should not include ‘new structural elements for the building’, where the conversion of agricultural buildings is proposed a prior approval application to the Local Planning Authority is required. Dwellings which are created via these provision are conditional on the accommodation being created meeting the nationally described minimum space standards, (Source: https://www.gov.uk /government /publications/technicalhousing-standards-nationally-described-space-­standard) and other provisions relating to natural light (windows) to habitable rooms. It is of note that whilst development is strictly controlled in areas designated as Green Belt, when a planning application to the Local Planning Authority is required, Green Belts are not Article 2(3) Land and therefore stricter controls over permitted development are not applied. However, Local Planning Authorities are able to, on application to the Government, restrict certain types of permitted development, if justification can be provided for their area. Such restrictions are made under Article 4 and can be checked with Local Planning Authorities.

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Other consents Listed buildings See websites for advice in Wales, Scotland and Northern Ireland. A Listed Building includes the exterior and interior of the building and, with some exceptions, any object or structure within the curtilage of the building, including garden walls. Listed Building Consent is needed to demolish a Listed Building, or part of one, or to alter or extend it in any way inside or out which would affect its architectural or historic character as defined by the Listed Building Officer. Certain minor works such as plumbing, electrical installations, and fitted furniture and appliances, as for kitchens and bathrooms, may be considered ‘de minimis’ and not require consent if the work is both non-destructive and reversible, but it is unwise to assume this. Check with the council first. It is a criminal offence to carry out any work without the required consent. No application fees are required (pre-application fees may be charged). Conservation areas Planning permission is needed to demolish any building in a Conservation Area with a volume of more than 115 m3 or a gate or fence more than 1 m high where abutting a highway, or more than 2 m high elsewhere. No application fees are required. National Parks, Areas of Outstanding Natural Beauty and the Broads, World Heritage Sites Generally, permissions to carry out building work in these areas are more limited, so check with the appropriate body first. Trees and high hedges Many trees have Tree Preservation Orders which mean consent is needed to prune or fell them. Most trees are protected in

Design guidance

45

Conservation Areas. In Conservation Areas, notice is required for works to trees that have a trunk diameter of more than 75 mm when measured at 1.5 m from ground level. Tall evergreen hedges over 2 m high may be subject to the Anti-Social Behaviour, Crime and Policing Act 2014. Flooding Flood risk is an increasingly common issue in planning application work and details of flood maps for planning are available online at the government’s website (https://flood-map-forplanning.service.gov.uk/) which provides guidance when planning a development. This map is for land-use planning. If you are planning a development in a potential flood risk area, you will need to undertake a more detailed flood risk assessment to show how the flood risk to the site, or elsewhere as a result of proposed changes to the site, can be managed as part of your development proposal. Local planning authorities should use this map alongside an up-to-date Strategic Flood Risk Assessment to: • Identify when a flood risk assessment is required. • Identify when a consultation with the Environment Agency is needed. • Apply the sequential test in the absence of a suitable Strategic Flood Risk Assessment. • Flood Zone definitions are set out in the National Planning Policy Guidance: °° Flood Zone 1: land assessed as having a less than 1 in 1000 annual probability of river or sea flooding (1%),

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or a 1 in 200 or greater annual probability of flooding from the sea (>0.5%) in any year. Note: These flood zones refer to the probability of river and sea flooding, ignoring the presence of defences. Flood defences shows flood defences built to protect against river floods with a 1% (1 in 100) chance of happening each year, or floods from the sea with a 0.5% (1 in 200) chance of happening each year, together with some, but not all, older defences and defences which protect against smaller floods. Flood defences that are not yet shown, and the areas that benefit from them, will be gradually added. Areas benefiting from flood defences are areas that benefit from the flood defences shown, in the event of a river flood with a 1% (1 in 100) chance of happening each year, or a flood from the sea with a 0.5% (1 in 200) chance of happening each year. If the defences were not there, these areas would be flooded. Flood defences do not completely remove the chance of flooding, however, and can be overtopped or fail in extreme weather conditions. For information on flood defences which are not yet shown on the map, contact your local Environment Agency office. Rights of way If a proposed building would obstruct a public path, then consult with the local authority at an early stage. If they agree to the proposal, then an order will be made to divert or extinguish the right of way. No work should proceed until the order has been confirmed. Advertising Displaying an advertisement larger than 0.3 m2 outside a property may need consent. This can include house names, numbers or even ‘Beware of the Dog’ signs. Temporary notices up to 0.6 m2 relating to local events may be displayed for a short time.

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47

Wildlife If the proposed new building or alterations will involve disturbing roosts of bats or other protected species, then Natural England (NE), the Countryside Council for Wales (CCW) or Scottish Natural Heritage (SNH), whichever is appropriate, must be notified. The possible delays and costs involved in dealing with protected species, for example, in avoiding disturbance during breeding or hibernation and in obtaining the necessary surveys and licences and carrying out mitigation works, can be severe. Pre-applications are helpful in defining whether particular ecological (and other) surveys are required. The Environment Act 2021 introduces a requirement for development to achieve a minimum (10%) biodiversity net gain, which will become mandatory via Regulations taking effect in 2023 (although there are exclusions relating to domestic alterations and other smallscale development). Source: Town and Country Planning (General Permitted Development) (England) Order 2015 www.planningportal.gov.uk Planning appeals The following relates to appeals in England. Similar processes are in place in Scotland, Wales and Northern Ireland. Considering an appeal It is possible to appeal against a Local Planning Authority (LPA) which has refused Planning Permission, whether outline or full; or if they have given permission but with conditions which seem to the Appellant to be unreasonable; or if a decision has not been made within the time laid down (without an extension being agreed), which is normally eight or thirteen weeks from registration. However, before lodging an appeal, the Appellant should consider modifying the scheme if this could meet the objections. Generally, if a revised scheme is presented within one year of the refusal date, no extra planning fee is requested. Appeals should be the last resort. They

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take time and cost money. The majority of appeals are not successful. Inspectors must take their decisions based on relevant facts and material planning considerations. They consider the planning merits of the case and personal considerations are unlikely to outweigh strong planning objections. Making an appeal Appeals must be lodged within six months of the date of the decision, or twelve weeks for householder appeals. The Secretary of State (SoS) can accept a late appeal, but will do so only in very exceptional circumstances. Most appeals are decided on the basis of written representations and a visit to the site by a Planning Inspector. The Inspectorate may agree to or require a Hearing or a Public Inquiry (it is also now possible for a mixed procedure to be used at an Inspector’s discretion). Appeals against the refusal of Planning Permission, Listed Building Consent or Conservation Area Consent can be submitted online or on forms which can be obtained from the Planning Inspectorate in England and Wales, the Scottish Executive (SEIRU) in Scotland and the Planning Appeals Commission in Northern Ireland. In England as well as having a reduced timescale for making an appeal, there is an expedited procedure for the consideration of householder appeals. Currently (other than in Northern Ireland), appeals can only be made by the applicant, not by any interested third party. Written representation The appeal form stating the grounds of appeal together with documents and plans should be sent to the Planning Inspectorate (PI). The LPA will send their case to the PI, copies of which will be sent to the Appellant who is allowed to make comments. Interested people such as neighbours and environmental groups will be notified of the appeal and are also able to comment. When the Inspector is ready, a site visit is arranged. This may be an unaccompanied visit if the site can be viewed from public land or an accompanied visit when the site is on

Design guidance

49

private land and where both the Appellant, or a representative, and the LPA must be present although only factual matters can be pointed out, no discussion is entered into. Hearings Hearings are less formal and therefore less expensive than a public inquiry and legal representatives are not normally used. This method is not usually suitable where there is unusual public interest in a case or where the evidence to be considered is particularly technical or complex. Local inquiry This procedure is used where requested by the LPA, the Appellant or the Inspectorate and when the Inspectorate agree to this procedure. The procedure is more formal and strict deadlines for the submission of evidence are imposed. All witnesses or representatives may be questioned or cross-­ examined. At the inquiry, anyone involved may use a lawyer or other professionals to make their case. The Inspector will make visits to the site usually alone, before the inquiry and accompanied as part of the inquiry. Costs The Appellant and the LPA will normally pay their own expenses, whichever procedure is used. However, either side can make a submission for the payment of costs where they consider that the behaviour of the other party has been unreasonable and therefore put them to unnecessary expense. Costs can be claimed for appeals following all methods (written representations, hearings or local inquiry) and may, in some cases, be awarded by an Inspector if he/she considers there to have been unreasonable behaviour even if a claim is not made by the other parties. The decision Where new evidence emerges before the decision is issued which may shed new light on the subject, both parties may

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have a chance to comment before a decision is made and an inquiry may be re-opened or further written submissions invited. The Inspector sends the decision to the Appellant with copies to the LPA and anyone else entitled or who asked for a copy. In some cases, the Inspector does not make the decision but makes a recommendation to the Secretary of State who considers the merits and makes the final decision. The High Court The only way an appeal decision can be challenged is on legal grounds in the High Court. This challenge usually has to be made within six weeks of the date of the decision, and should in all cases be made promptly. For a High Court challenge to succeed, it must be demonstrated that the decision made is unlawful and that the Inspectorate or the SoS has exceeded their powers or that proper procedures were not followed. If the High Court appeal succeeds, it only means that the case has to be heard again, it may not change the ultimate outcome. Sources: Planning Portal: www.planningportal.gov.uk Procedural Guidance: Planning appeals – England (April 2022) https://www.gov.uk/government/publications/ planning-appeals-procedural-guide

Party Wall Awards The Party Wall Etc. Act 1996 has effect throughout England and Wales and involves the following proposed building work: 1. Work to an existing party structure, wall or floor, such as taking support for a new beam, inserting DPCs, underpinning, raising, rebuilding or reducing the wall. 2. Building a new structure next to a boundary and building a new party wall astride a boundary line between two properties.

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3. Any excavations which may include foundations for a new building within 3 m of a neighbouring building or structure, where the digging will go deeper than the neighbouring foundations. 4. Excavations within 6 m of a neighbouring building or structure where the digging will cut a line drawn downwards at 45º from the bottom of the neighbour’s foundation, which includes piled foundations, services and drains. Notices must be served by the building owner on the adjoining owner or owners, which may include landlords as well as tenants with a lease of more than 1 year. A Party Structure Notice for works in paragraph 1 above must give at least 2 months before the work starts on site. A Line of Junction Notice for works under paragraph 2 and a Notice of Adjacent Excavation for works under paragraphs 3 and 4 must give 1 months’ notice in advance of work commencing on site. There is no set form for the Notice, but it should include: the building owner’s name and address; the address of the building site (if different); the name and address of the adjoining owner and the address of their adjoining property (if different), full detailed drawings of the proposed work; and the proposed starting date. It may also include any proposals to safeguard the fabric of the adjoining owner’s property and details of any proposals for access and scaffolding, etc. on the adjoining owner’s property. The adjoining owner cannot stop someone exercising their rights under the Act, but they can influence how and when the work is done. Anyone receiving a notice may give consent, dissent, or serve a counter-notice setting out their proposed modifications to the works. If the adjoining owner does not consent within 14 days, a dispute is deemed to have arisen and the dispute must be resolved by way of a Party Wall Award. Notices and awards must be served in person, or by post, if the recipient has not already consented (in writing) to receipt by email. Both methods can be used; email to speed up the

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process, and then post the important documents to be legally sure of service. The full process can be costly, so it is well worth clients preparing the ground with good neighbour communication.

The Award The Party Wall Act is to safeguard the interests of the owners and resolve any disputes regarding the proposed works and how it is to be carried out. It is there to prevent confrontation between neighbours and although the adjoining owner can “dissent” to the work that does not give them a veto to prevent the work being carried out. When consent is not received, the two owners may concur and appoint one agreed surveyor to resolve the dispute by way of a Party Wall Award, or they may each appoint separate surveyors to do the same job. The Surveyors so appointed must take into account the interests of both owners and dispassionately administer the Act. They draw up and make their Award, which is a legally binding document and sets out the rights and responsibilities of the parties. It also sets out what work will be undertaken and how and when it will be done. It will usually include a Schedule of Condition, which describes in detail the state of the adjoining owner’s premises prior to commencement of works and provides a useful benchmark should damage unfortunately occur. The Award will also specify who pays the construction costs and the surveyors’ fees – usually the owner who initiates the work. The Award is served on all relevant owners, each of whom is bound by the Award unless an appeal is made to the County Court within 14 days of its service. Sources: Party Wall etc. Act 1996: revised explanatory Booklet Available online from www.gov.uk/government/ publications/preventing-and-resolving-­disputes-inrelation-to-party-walls

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Building Regulations Almost all new building must comply with the Building Regulations except small, detached buildings without sanitary facilities such as sheds and garages. The regulations are available to download from www.planningportal.co.uk. Applications can be made to any Local Authority or to registered private Building Inspectors. Fees for smaller works are displayed on the LA website; fees for larger works are by arrangement.

The approved documents These documents are published as practical guidance to the Building Regulations; that is, they are not the Building Regulations as such. The mandatory Requirement is highlighted in green near the beginning of each document. The remaining text is for guidance only. The Building Inspectorate accepts that if this guidance is followed then the requirement is satisfied. There is no obligation to comply with these guidelines providing evidence is produced to show that the relevant requirement has been satisfied in some other way. The purpose of the Building Regulations is to secure reasonable standards of health, safety, energy conservation and the convenience of disabled people. A separate system of control applies in Scotland and Northern Ireland. The regulations are available from RIBA Bookshops and free to download online. https://www.gov.uk/government/collections/ approved-documents

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Approved Documents Part A Approved Document A – Structure (2004 Edition incorporating 2004, 2010 and 2013 amendments) Part B Approved Document B – Fire safety Volume 1: Dwellings (2019 edition incorporating 2020 amendments) Approved Document B – Fire safety Volume 2: Buildings other than dwellings (2019 edition incorporating 2020 amendments) Part C Approved Document C – Site preparation and resistance to contaminates and moisture (2004 Edition incorporating 2010 and 2013 amendments) Part D Approved Document D – Toxic Substances (2010 edition incorporating 2010 and 2013 amendments) Part E Approved Document E – Resistance to the passage of sound (2003 Edition incorporating 2004, 2010, 2013 and 2015 amendments) Part F Approved Document F – Ventilation Volume 1: Dwellings (2021 edition) Approved Document F – Ventilation Volume 2: Buildings other than dwellings (2021 edition)

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Part G Approved Document G – Sanitation, hot water safety and water efficiency (2015 edition with 2016 amendments) Part H Approved Document H – Drainage and Waste Disposal (2015 edition) Part J Approved Document J – Combustion appliances and Fuel Storage systems (2010 edition incorporating 2010, 2013 and 2022 amendments) Part K Approved Document K – Protection from falling, collision and impact (2013 edition) Part L Approved Document L – Conservation of fuel and power, Volume 1: Dwellings (2021 edition) Approved Document L: Conservation of fuel and power, Volume 2: Buildings other than dwellings, (2021 Edition) Part M Approved Document M – Access to and use of buildings, Volume 1: Dwellings (2015 edition incorporating 2016 amendments) Approved Document M – Access to and use of buildings, Volume 2: Buildings other than dwellings (2015 edition incorporating 2020 amendments) Part O Approved Document O – Overheating (2021 edition)

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Part P Approved Document P – Electrical safety, Dwellings (2013 edition) Part Q Approved Document Q – Security, Dwellings (2015 Edition) Part R Approved Document R – Physical infrastructure for high-speed electronic communications networks (2016 Edition) Part S Approved Document S – Infrastructure for the charging of electric vehicles (2021 Edition) Approved Document 7 – Materials and workmanship (2013 edition incorporating 2018 amendments)

2022 Building Regulations – revisions and additions From June 2022, updated regulations apply with respect to Approved Documents Part F (ventilation) and Part L (conservation of fuel and power). Part J revisions apply from October 2022 and Part M revisions from 2023. New Approved Documents also apply: Part O for overheating and Part S for charging infrastructure for electric vehicles. The majority of the changes are interim measures on the paths to the Future Homes Standard and Future Buildings Standard – both due in 2025 under which all new buildings will be capable of net zero carbon operation once the electric grid is decarbonised.

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Significant changes: Part F: means of ventilation – June 2022 Now split into Volume 1: Dwellings and Volume 2: Buildings other than dwellings (no changes) Volume 1: Dwellings: Three systems identified: 1. Natural ventilation – intermittent extract with background ventilation suitable for less airtight dwellings (i.e. those with design permeability higher than 5m3/h.m2 or as-built higher than 3m3/h.m2 @ 50 Pa). 2. Continuous mechanical ventilation suitable for all dwellings. 3. Continuous mechanical ventilation with heat recovery for dwellings, especially the more airtight. For mechanical systems, minimum boost rate unchanged but trickle rates increased by 30%; fan units noise not to exceed 30dB L Aeq.T/NR35 in bedrooms and living rooms (unchanged) and 45dB in kitchens and bathrooms (previously 35dB). Reasonable maintenance access now required for fans, filters, coils and ductwork. Designs to minimise air pollutant intake where local air quality poor. Commissioning procedures now require approval. Where conflicts arise between Part F and other regulations B, J, K, L, M & O, the latter take precedence. Part J – Combustion appliances and fuel storage October 2022 Part J – Combustion appliances and fuel storage is revised in three ways: 1. The guidance on smoke control areas and the interaction with the Clean Air Act 1993 has been updated to reflect the interaction with the Environment Act 2021.

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2. The guidance on installing carbon monoxide (CO) detectors, to satisfy requirement J3, has been extended into sections 3 and 4 to cover both gas and oil burning appliance installations. The previous guidance on CO detectors, contained in section 2 for solid fuel appliances, has also been amended. 3. Table 10 in section 5 (Provisions for protecting structures for liquid fuel storage and supply) has been amended to include some missing text in bullet a) of column 2 so it now reads, Make building walls imperforate (1) within 1800mm of tanks with at least 30 minutes fire resistance (2) to internal fire and construct eaves within 1800mm of tanks and extending 300mm beyond each side of tanks with at least 30 minutes fire resistance to external fire and with non-combustible cladding

Part L – conservation of fuel and power – June 2022 New domestic buildings to generate 31% less carbon emissions. New non-domestic buildings to generate 27% less carbon emissions. ‘Primary energy’ to be used to measure buildings’ energy efficiency in heating and cooling that includes both delivery and energy generation efficiencies. Reduced U-value limits are required in new domestic and non-domestic buildings: worst limits: 0.18 W/m2 for floors; 0.26W/m2 for walls; 0.16W/m2 for roofs; 1.6 W/m2 for windows, doors and rooflights. However, compliance with these U-value limits is not enough in itself since the proposed building has to still outperform the notional models: Domestic buildings notional model: floors at 0.13 W/m2; walls at 0.18 W/m2; party walls at 0.0 W/m2; roofs at 0.11

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W/m2; external doors at 1 W/m2; windows and rooflights at 1.2 W/m2; air permeability below 5AC/hr; ventilation: intermittent extract; low y-value thermal bridging; 80 Lm/W lighting; heating & DHW by gas at 89.5% efficiency with zoned controls; waste water heat recovery on all showers with max flow rate of 8L/minute; PVs area for 40% building footprint. Non-domestic notional model: floors 0.15W/m2; walls 0.18W/m2; roofs 0.15W/m2; windows 1.4W/m2; rooflights 2.1W/m2; large/high use external doors 1.9W/m2; other external doors 1.3W/m2; air permeability below 3AC/hr for side-lit space and below 5AC/hr for top-lit space; ventilation: intermittent extract; lighting 95 Lm/W; heating & DHW: gas 86%, HP 264%, DE 134%; glazing G-value 29%, LT 60%; hot water secondary circulation and storage accounted for; PVs area based on algorithm for foundation area, conditioned area and number of floors; default thermal bridging increasing from 10% to 25% of rated element U-values. New and replacement heating systems for all buildings to have a maximum flow temperature of 55°C. Existing non-domestic buildings heating and hot water system efficiencies improvement required via new controls, and minimum lighting efficacy standards raised to 80 luminaire lumens per circuit watt for display lighting and 95 for general lighting. Trickle ventilation now required for non-domestic buildings; new office buildings to be provided with CO2 monitors, along with a minimum air supply rate of 0.5 L/sec/m2. The Fabric Energy Efficiency Standard in new domestic buildings will be set by a full fabric specification; SAP compliance will be required of all domestic extensions. All new domestic buildings need to be air tightness tested. Operation and Maintenance Manuals (non-technical) to be provided to all first occupants and to contain information on building services, operation and maintenance; the EPC and Home User Guide, plus photographs of the building’s construction.

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Part M – Access to and use of buildings – proposed revisions after consultation – 2022/2023 The Government is proposing to mandate option 2 in the ­consultation – the current M4(2) (Category 2: Accessible and adaptable dwellings – essentially the ‘Lifetime Homes’ ­standard) – as a minimum standard for all new homes. Where M4(2) is impractical the lower M4(1) standard will apply. Local authorities will also be able to specify in their local plans a proportion of new homes to be built to the M4(3) standard – fully wheelchair accessible – where a need has been identified and evidenced. Part O – Control of Overheating – June 2022 Part O introduces maximum glazing limits in new domestic buildings, care homes, schools and student accommodation together with cross-ventilation requirements. The Simple Assessment route via new SAP software will severely restrict window areas according partly to cross-ventilation provision; the Dynamic Assessment route using TM59/52 modelling makes for a less prescriptive design; overheating strategy has to be included in the Home User Guide. Part S – EV Charging infrastructure for domestic buildings – June 2022 Part S requires all domestic buildings to have at least preparatory work included for future electric vehicle charging point installations up to a cost limit of £3600 per charge point. The changes apply to all work submitted from June 2022, and to all work from June 2023.

Future Homes Standard 2025 From 2025, the Future Homes Standard – in parallel with Building Regulations – will require CO2 emissions produced by new homes to be 75–80% lower than those built to current (2021)

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standards. Homes will need to be built ‘zero carbon ready,’ with no retrofit work required to benefit from the decarbonisation of the electricity grid and the electrification of heating. Fossil fuel heating (such as gas or oil boilers) will be banned in new homes, with an expected shift to reliance on heat pumps and heat networks, though the potential use of zero carbon hydrogen remains a possibility. The Future Buildings Standard has similar aims for non-domestic buildings and a full technical specification for both standards will be consulted on in 2023, ahead of full implementation in 2025.

Dampness in buildings Dampness becomes a problem in buildings when there’s too much of it in the wrong place, such that contents or finishes are damaged, or mould growth is stimulated that threatens health or further deterioration of the building fabric. There are five main categories of damp problem – rising damp, penetrating damp, condensation, leaking services, and construction moisture – though in many instances poorly finished or maintained buildings are affected by more than one of these; diagnosis can be complex and symptoms should be assessed over time. Damp building fabric can take months and sometimes years to dry out after remedial works, so making good needs to employ damp tolerant materials and finishes, typically avoiding gypsum plaster and vinyl-based emulsion paints. Some kinds of timber fungal decay and insect attack require dampness to progress; despite its name, ‘dry rot’ requires damp (but not wet or dry) conditions to spread, so buildings can be especially susceptible during the process of drying out from construction or remedial works; woodworm spreads more readily in damp timber with moisture content above 12%; both powder post and deathwatch beetles affect hardwoods more severely in damp conditions.

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Typical causes

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Construction Design and Management Regulations In the mid-1990s, fatal accidents in the construction industry were five to six times more frequent than in other areas of manufacture. Also, all construction workers could expect to be temporarily off work at least once in their working life as a result of injury. The Construction Design and Management Regulations (CDM) 1994, effective from 31 March 1995, were drafted to try and improve these statistics. The regulations were revised and clarified in 2007 and again in 2015; they are explained in the Approved Code of Practice ‘Managing health & safety in construction’ (2015 revision). Designers are required to avoid foreseeable risks “so far as is reasonably practicable, taking due account of other relevant design considerations.” The greater the risk, the greater the weight that must be given to eliminating or reducing it. For all projects, designers should check that clients are aware of their duties, and before they start design work on ‘notifiable projects,’ they should ensure that clients have appointed a ‘Principal Designer’ for CDM purposes. The key aims of the CDM Regulations are to integrate health and safety into the management of the project and to encourage everyone involved to work together to: • improve the planning and management of projects from the very start; • identify hazards early on, so they can be eliminated or reduced at the design or planning stage and the remaining risks can be properly managed; • target effort where it can do the most good in terms of health and safety; and • discourage unnecessary bureaucracy.

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The 2015 Revisions to the regulations have emphasised the client’s responsibilities as the primary instigator of compliance with the regulations, have brought virtually all construction including most domestic project work fully within the regulations and redefined the early central role as more explicitly a member of the design team – ‘Principal Designer’ rather than ‘CDM Coordinator,’ while continuing to warn against inappropriate bureaucracy, which tends to obscure the real health and safety issues. For all construction projects with more than one contractor – or subcontractor – working at once, the client is required to appoint a Principal Designer and a Principal Contractor. There has been the least change in CDM 2015 to the Principal Contractor’s duties. All construction projects are now ‘notifiable’ unless they will last less than 30 days and involve no more than 20 workers at once, or require less than 500 person-days of construction work: therefore a typical domestic project involving 5 workers for 5 months is just notifiable. Notification is a client duty but is often transferred to the Principal Designer who both advises and assists a domestic client: it involves submission of project details on an F10 form to the HSE, including updating as the project develops. The Principal Designer must advise and assist the client with their duties, co-ordinate health and safety aspects of design work and co-operate with others involved with the project; facilitate good communication between client, designers and contractors; collect and pass on pre-construction i­nformation – the Pre-Tender Health & Safety File – and liaise with the Principal Contractor regarding ongoing design; identify and prepare/ update the Health & Safety file for the client on completion. They may also, if requested by a client, advise on the appointment of consultants and contractors as to their competence and resources in regard to CDM matters. If architects are to act as Principal Designers, they must ensure that they receive

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appropriate CDM training, as failure to comply with the regulations could lead to criminal prosecution. For architects not acting as Principal Designers, the most explicit duty is in preparing risk assessments for the project to inform the ongoing design process. The RIBA advised as follows regarding architects as Principal Designers: The Principal Designer duties are overseen by a principle of so far as reasonably practicable and are therefore not absolute obligations. The Principal Designer role is not excessively complex, nor does it involve an overly onerous set of tasks for an experienced designer. The Principal Designer role is not about an endless round of administration, but rather a practical, design-based focus on real risk prevention in relation to health and safety. The Principal Designer role is not something designers and in particular architects should shy away from. On more complex projects, architects may wish to appoint a specialist Health and Safety Adviser to advise and assist them in discharging their duties as Principal Designer. Does the architect have to undertake the Principal Designer role? No, but the Principal Designer must be a designer with meaningful responsibility and authority over the co-ordination of the pre-construction phase design. While this role can be undertaken by any of the designers on the project design team who can control the pre-construction phase of the project, the architect or lead designer would appear to be the natural choice for the role on most building projects. Where a domestic client fails in their duties – for example to appoint a Principal Designer, or Principal Contractor, those duties fall on the lead designer or lead contractor respectively, as per HSE advice:

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On a domestic client project where the domestic client does not appoint a principal designer, the role of the principal designer must be carried out by the designer in control of the pre-construction phase. When working for a domestic client, the client duties will normally be taken on by another dutyholder (often the principal contractor on projects involving more than one contractor). However, the principal designer can enter into a written agreement with the domestic client to take on the client duties in addition to their own. The Building Safety Bill of 2021 proposed that both Principal Designers and Principal Contractors working in CDM should take on roles with respect to the implementation of Building Regulations but such changes have not been made explicit in 2022 Building Regulations revisions. When CDM regulations are not applicable in full – ‘not notifiable’ – or below the threshold for appointment of Principal Designer and contractor – that is, with a single contractor: The designer is still legally obliged to avoid foreseeable risks; give priority to protection for all; and include adequate H & S information in the design. There are a number of construction-related activities that are listed as ‘not construction’ for the purposes of the regulations, including erecting and dismantling marquees, lightweight movable partitions as used for office screens, exhibition displays, etc.; tree planting and general horticultural work; surveying including ‘examining a structure for faults,’ and off-site manufacture of construction components, for example, roof trusses, precast concrete and bathroom pods. CDM, therefore, does not apply to these works. Source: Managing Health and Safety in Construction – ­Approved Code of Practice 2015 HSE (available as a free download)

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Standards – in the construction industry The UK left the EU in January 2021; www.legislation.gov.uk is where you can find legislation originating from the EU as it now applies in the UK. Listed alphabetically below are the organisations and standards involved, which be useful sources of information.

BBA – British Board of Agrément. www.bbacerts.co.uk This organisation assesses and tests new construction products and systems that have not yet received a relevant BS or EN. It issues Agrément Certificates to those that meet their standards. The Certificate gives an independent opinion of fitness for purpose. Holders are subject to 3-yearly reviews to ensure standards are maintained.

BSI – British Standards Institution. www.bsigroup.com Since 1 January 2021, the UK no longer aligns with the rules or obligations of the EU, with the exception of Northern Ireland which continues to follow certain regulations. As part of its role as National Standards Body, BSI develops policy positions to reflect the views and interests of its stakeholders, including government. European regional standards are developed where there are no international standards or where there are specific interests in the region that could not be addressed globally. International and European standards are adopted for the whole of the UK as British Standards, alongside a diminishing proportion of national-only standards that meet purely local needs. These national standards are often developed as precursors to international work and are transferred into international processes in due course.

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BSI will continue to promote and enable UK stakeholder leadership in the development of international and European regional standards and optimise the participation of UK stakeholders. The BIM suite of documents consists of ISO 19650-2, ISO 19650-3, ISO 19650-5, BS 1192-4:2014, PAS 1192-6.

CE mark – Communauté Européenne mark (also see UKCA below) The letters ‘CE’ appear on many products traded on the extended Single Market in the European Economic Area (EEA). They signify that products sold in the EEA have been assessed to meet high safety, health and environmental protection requirements. From January 2023, manufacturers that have or want to introduce products onto the UK market will need a UK Conformity Assessed (UKCA) Marking instead of CE marking.

CEN – European Committee for Standardisation www.cencenelec.eu This is an association that brings together the National Standardisation Bodies of 34 European countries. CEN provides a platform for the development of European Standards and other technical documents in relation to various kinds of products, materials, services and processes. BSI continues to be a member of CEN and CENELEC General Assemblies.

EMS – Environmental Management System ISO 14001 helps businesses of all sizes across all sectors make their day-to-day operations more sustainable. Sustainability can ultimately save money, improve brand reputation, engage employees and build resilience against uncertainty as well as the ability to rapidly adapt to change.

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EN – Euronorm (also known as European Standard) and Eurocodes. www.en-standard.eu European standards (ENs) are Europe-wide standards that help in developing the entire European market for goods and services in all sectors. The intention of ENs is to facilitate trade between countries, create new markets and cut compliance costs. ENs are produced by the following European standards organisations: The European Committee for Standardisation (CEN); The European Committee for Electro-technical Standardisation (CENELEC); The European Telecommunications Standards Institute (ETSI). In the UK, ENs are published by the British Standards Institute (BSI) as BS ENs.

ISO – International Organization for Standardization: www.iso.org This organisation prepares International Standards for the whole world. They are prefixed ISO and many are compatible and complement British Standards. In the UK, BSs and ENs that are approved by the ISO are prefixed BS ISO or BS EN ISO. ISO International Standards ensure that products and services are safe, reliable and of good quality. For business, they are strategic tools that reduce costs by minimising waste and errors and increasing productivity. They help companies to access new markets, level the playing field for developing countries and facilitate free and fair global trade. MOAT – Method of Assessment and Testing These are the criteria and methods used by the BBA when testing products. Many MOATs have been developed in consultation with the European Agrément organisations under the aegis of the UEAtc.

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QMS – Quality Management System ISO 9001 is the world’s most widely recognised Quality Management System (QMS). It belongs to the ISO 9000 family of quality management system standards (along with ISO 9004), and helps organisations to meet the expectations and needs of their customers, amongst other benefits. ISO 14001 is an internationally accepted standard that outlines how to put an  effective environmental management system in place in an organisation. It is designed to help businesses remain commercially successful without overlooking environmental responsibilities and impacts. It can also help businesses to grow sustainably while reducing the environmental impact of this growth. UEAtc – European Union of Agrément technical committee A technical committee to which all European Agrément institutes belong, including the BBA for the UK. Its principal function is to facilitate trade in construction products between member states, primarily through its Confirmation process, whereby an Agrément Certificate issued by a UEAtc member in one country can be used to obtain a Certificate in another. UKCA – UK Conformity Assessment mark This is the new UK product marking that will be required for certain products being placed on the market in Great Britain (England, Wales and Scotland). It covers most products that previously required the CE mark. It will not be recognised in the EU market. Products that require CE marking will still need a CE marking to be sold in the EU.

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Cost estimating, contracts, fees, disputes and legal involvement for architects Pre-contract cost estimating Costs and legal issues are described in principle and in outline only since both contract values and case law change too frequently for actual figures and legal detail to have lasting value.

Costs The architect’s role as a cost advisor varies with the scale of projects. For most small projects and many of the simpler ­medium-scale ones, the architect is both the client’s cost advisor and the certifier of payments due to the contractor: awareness of current costs is therefore vital to architects working at this level with local experience usually the best guide, though several price books are available including those covering small works and refurbishment. On larger projects (see below), the client may appoint a Quantity Surveyor as cost adviser; however in all cases the architect remains responsible for certifying interim payments. The simplest rule in estimating costs is that they decrease with scale (i.e., larger quantities should mean a decrease in cost) and increase with complexity; time is also an issue but the most economic length of time for a construction project will vary for different contractors and circumstances; either forcing the pace for an earlier completion or slowing progress artificially may increase costs. Project costs can be lower in the early stages of simpler less skilled work and cheaper materials and increase sharply towards completion as more skilled trades are required for services and finishing and more expensive components are fitted such as joinery, electrical and sanitary fittings. Labour costs have grown steadily as a proportion of construction costs, which is reflected in the growth of prefabrication

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and pre-finishing both of components such as windows, kitchens and bathroom pods, and of material elements such as wall, roof and floor panels; renewed enthusiasm for prefabrication has coined the term ‘Modern Methods of Construction.’ Preliminary cost estimating for most projects is initially done on a pounds per square metre of internal floor area basis; the rates for different types and scales of buildings vary sharply, so that, for example, a simple industrial shed may cost half as much per square metre as speculative housing, which in turn may cost half as much per square metre as a hospital. Despite the decades since metrication, many in the commercial development world still work in square feet for both rents and build costs (10.67 sq. ft = 1 sq. metre). On larger projects, elemental cost plans are often required. For smaller projects, where the architect is often the client’s only cost advisor, the work is typically tendered on the basis of drawings and a specification or schedule of works. The architect will agree the list of contractors with the client, issue the tenders, advise the client on the relative merits of the tenders received, negotiate any cost savings needed and arrange the contract between client and contractor; once the work starts, the architect will administer the contract on behalf of both parties, value the contractor’s work – usually at monthly ­intervals  – and prepare certificates for the client to pay, including where necessary any variations in the work covered by architects instructions. After completion, the architect negotiates the final account with the contractor. The generally accepted principle in building contracts is that the contractor is paid in arrears for work done; some contractors may seek to be paid in advance or at close intervals so as to ease their cash flow: this puts the client at risk and is seldom advisable. More frequent payments than the monthly norm may be acceptable but involve additional valuation and certification costs for the architect and QS – with additional fees for clients. Where contractors need to order and pay for particular items in advance, for example, bespoke windows, special

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precautions are required to protect the client’s interests such as validation of receipts, clarity of ownership and insurance. Larger projects – and especially those where the client wants detailed and explicit cost estimating, monitoring and ­control – usually include a Quantity Surveyor in the consultants’ team who may provide a series of estimates and carry out value engineering exercises during the briefing and design process, and then prepare a Bill of Quantities during the working drawings stage which describes the works in sufficient numeric detail so that tenderers can quote precisely against the Bill. The QS advises the client on tenders received and prepares valuations during the contract as a basis for the architect’s certificates, as well as dealing with the final account. Whether or not a QS is involved, the architect is still responsible under most forms of contract for certifying payments although these are generally based on valuations prepared by the Quantity Surveyor. The architect also takes on the additional role of ‘administering the contract’; in some of his duties, for example, when assessing extensions of time, he is required to act fairly and impartially to both client and contractor in matters of cost, timing, quality, etc. It is important that architects make this clear to inexperienced clients at the outset. One of the architect’s most important duties relates to assessing extensions of time that can have substantial cost consequences  – both in terms of contractors’ claims for loss and expense, and reductions of clients’ rights to liquidated damages.

Interim Certificates Most forms of contract, including the JCT family, make provision for interim payments (or progress payments) to be made by the Employer to the Contractor at regular intervals during the course of the Works. The normal interval is monthly.

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The Housing Grants, Construction and Regeneration Act 1996, 2011 Amendment (‘the Construction Act’) set new rules for such interim payments with which all construction contracts are required to comply. These rules include various timescales for the issue and payment of interim certificates. As part of the rules for interim payments, the Construction Act also made provision for Payment Notice and Pay Less Notices and the timescales for issue of such notices are strict and absolute such that any non-compliance can result in loss of Employer rights. For example, under the JCT family of contracts, the Contractor may submit its monthly valuation stating the value of works it has carried out within the previous month. The Contract Administrator’s (CA) duty is to assess whether such claimed value is reasonably accurate and contractually compliant for which purpose the CA may instruct the Quantity Surveyor to carry out a valuation. The CA must then issue an interim certificate within the timescale set by the Contract. Such interim certificate stands as a Payment Notice under the Contract; that is, it sets out the value of work considered by the Employer to be due to the Contractor for that particular month. In practice, the CA’s interim certificate (or Payment Notice) often differs from the Contractor’s own valuation of work. However, if the interim certificate is not issued within the contract timescale (or at all), then the Contractor’s monthly valuation will stand as the Payment Notice and the amount therein becomes due from Employer to Contractor. There is no defence to this situation, therefore if the Employer considers the Contractor’s valuation to be above the true and correct value of work, the Employer must still pay. Such situations have often resulted in what are commonly termed ‘smash and grab’ adjudications whereby Employer refuses to pay the full amount of what he considers an over-valuation of the work and the Contractor instigates adjudication proceedings (see ‘Dispute Resolution’). The strict timescales for the issue of Payment Notices require the Adjudicators must instruct payment as the Payment Notice even if the amount of such payment is patently incorrect. Hence the term ‘smash and grab.’ It is therefore critically important that

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interim certificates (Payment Notices) comply with contractual timescales. A Payment Notice therefore is the Employer’s opinion of the value of work carried out within the interim payment timescale (a month). However, if the Employer has a counterclaim against the Contractor, for example liquidated damages, then he must also issue a Pay Less Notice, again within strict timescales set out in the Contract. So the Payment Notice is the Employer’s notice of the amount due in any one month and the Pay Less Notice the amount will deduct from the Payment Notice in respect of any counterclaims he may have. Again, if the Pay Less Notice is not issued in time, then no deduction can be made.

Extensions of Time Most construction contracts, in particular the JCT family, specify a date for commencement of the Works and a date for completion. Such contracts also contain provisions for the completion date to be extended if the Contractor is delayed by reason of various events beyond his control. Such events may be neutral, for example weather or the responsibility of the Employer, for example instructions for additional work or the late issue of design information by the Employer. If the Contractor considers that the works will be delayed by reason of one or more of the delay events set out in the Contract, then he must give notice of the same to the CA together with details of the expected impact on the date for completion. The CA must then assess (1) whether the cause is a matter that entitles an extension of time under the contract and (2) the extent of such extension. He then sets a revised date for completion. It has been held by legal case law that when the CA considers any application by the Contractor for an extension of time, he has a duty to both Employer and Contractor to assess impartially and without bias to either party. Unlike other duties under the Contract where the CA acts as agent for the Employer

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(e.g. scheduling defects), the CA’s duty regarding extensions of time is quasi-arbitral, he sits between Employer and Contractor and must make a professional and impartial judgement. Whilst the CA can take such advice as he may require in coming to such decisions, he must not, under any circumstances, allow the Employer to dictate such a decision. Extensions of time must be the judgement of the CA alone.

Fees and appointments There are no set fee scales for architects and the only advice that RIBA is allowed to give on fee levels is based on average fees charged, broad band graphs of which are included in their advice to clients. For larger projects, fees are often charged on a percentage of final construction cost; smaller projects may be carried out on a time basis or against lump-sum quotations. As for construction costs, fees tend to decrease with project scale and increase with complexity, so, for example, fees for a large new build warehouse on a greenfield site may be below 5% whereas the restoration and conversion of a small grade 1 listed building to a private home might involve fees as high as 20%. Fee percentages are calculated against final construction cost. RIBA’s appointment documents advise what standard services are normally included within an architect’s fee and what special services need to be separately negotiated. Where several consultants work on a project, their fees will be individually negotiated with the client but it is important that each consultant’s scope of work is clearly defined, so that there are neither gaps nor duplication in the service to the client. For a project with an overall fee of 15%, the split between consultants might be: architect 7%; landscape architect 1.5%; structural engineer 2.5%; services engineer 1.5%; quantity

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surveyor 2% and CDM Principal Designer 0.5% – though projects can involve very different relative demands for consultants’ skills.

Dispute resolution It is relatively common in construction contracts for disputes to develop between Employer and Contractor. Such disputes generally involve both time and money, for example, entitlement to extensions of time and associated costs, variations and defects. It is always recommended that the most beneficial means of resolving disputes is by mutual agreement or perhaps by some form of alternative dispute resolution (‘ADR’) such as mediation or expert determination. However, should settlement of any dispute not be possible by these means, then building contracts will usually contain provisions for the formal settlement of disputes. The principal method of formal dispute resolution at the current time is Adjudication, a process that was introduced under The Housing Grants, Construction and Regeneration Act 1996, (‘the Construction Act’). The process of Adjudication was introduced under the Construction Act as a means of making dispute resolution faster and considerably less costly, a benefit to all parties. As a consequence of the Construction Act, all building contracts were required to include the provision for Adjudication as a right for both parties. The parties therefore have both a statutory right to Adjudication (under the Construction Act) and a contractual right (under the Contract). Therefore, if a Contract fails to provide for Adjudication either by error or by deletion of that provision, the Parties still have a statutory right to Adjudication. However, it is important to note that the Construction Act does not apply to private householders or individuals, therefore if there is no Adjudication provision under the building contract, there is no statutory right to Adjudication and all the benefits of the Adjudication process are lost.

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The Adjudication process itself is a ‘fast track’ means of dispute settlement: Notice of Adjudication may be given at any point during the Works provided a dispute has arisen. An Adjudicator is then appointed by the specified body in the Contract and the whole process has to be resolved within one month of the Adjudicator’s appointment (unless the Parties agree to extend). As a consequence, it is an extremely cost-effective means of settling disputes but although ‘fast-track,’ it should be remembered that it is still a formal legal process and therefore formal rules and protocols apply. It should also be noted that Adjudication is not the final process for dispute resolution under the contract. If one party is unhappy with the Adjudicator’s Decision, that party may refer the matter to Arbitration or the Court (whichever is specified in the Contract). However, the Adjudicator’s Decision is binding upon the Parties until such time as it may be overturned by Arbitration or the Court. In practice, however, it is rare for parties to refer matters on to Arbitration or the Court given that the dispute has already been determined by an independent and professional third party (i.e. the Adjudicator). In practice, therefore, Adjudication is normally the final result. As regards the costs of Adjudication, both Parties must bear their own legal costs but the Adjudicator’s own fees and expenses may be allocated to either Party in such proportion as the Adjudicator considers appropriate. If the Parties choose not to refer any dispute to Adjudication as is their right or if either party is unhappy with an Adjudicator’s Decision, then the dispute may be referred to either Arbitration or to the Court (which process is specified in the Contract). In practice, both processes follow similar rules and protocols and both have similar time scales and costs. However, under Arbitration, the Arbitrator is normally a technical person (i.e. Architect, Engineer, Quantity Surveyor, etc.) whereas in Court the dispute is heard before a Judge. Both processes can be lengthy and costly in terms of the Parties’ legal costs (e.g. solicitor, barrister, expert witnesses). It is not unknown for legal costs to outweigh the amount in dispute in some circumstances (hence

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the introduction of Adjudication). The Arbitrator or Judge will normally direct that the ‘winning’ party’s costs are paid by the ‘losing’ party who also have to bear their own costs.

Legal involvement for Architects The Architects’ role in the administration of construction contracts is their main area of legal involvement but they may be asked by clients for legal advice in relation to Planning, Listed Buildings and Building Regulations, or in connection with health and safety under the CDM regulations (see p. 53), or boundary matters under the Party Wall Act (see p. 47), or a number of other relevant items of legislation such as Health & Safety at Work Act, Offices Shops & Railway Premises Act, etc. It is important that architects do not give clients advice beyond their expertise in legal matters and recommend their clients consult legal advisors when appropriate. Legal disputes, particularly where litigation and arbitration are involved tend to be time consuming and costly; The Construction Act (The Housing Grants, Regeneration and Construction Act Part II 1996 amended 2011) introduced adjudication as a simpler and swifter method of dispute resolution but it has its own rules and timetables of which architects need to be aware, particularly as timescales can be very tight. Although the availability of adjudication is obligatory in construction contracts generally, this does not apply to domestic projects: so architects should check with domestic clients whether they require it; it can be suggested that not deleting adjudication from a domestic contract can place the client at greater risk, so rendering the architect liable. Architects should also remember that their own appointments with their clients are classed as construction contracts under the Construction Act, and they can, therefore, avail themselves of such remedies as the Act provides, such as: adjudication, suspension of services, right to staged payments, etc. Disputes often arise between client and contractor over the architect’s extension of time award so architects should always

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maintain proper records of how they assessed extensions of time and the criteria used in coming to a judgement. RIBA architects can obtain initial informal legal and contractual advice at no cost by phone via the RIBA. Architects will need to consult their professional indemnity insurers or brokers when a dispute arises that might involve a claim against them. It may be more helpful to consult a professional contractual consultant in the first instance rather than a lawyer for advice on contractual disputes or claims. Registered architects – and practising members of RIBA – are requi­red to carry appropriate levels of professional indemnity in­su­ rance so that there is assurance of redress for clients – or others – who may suffer financially as a result of an architect’s mistakes. In the years since the Grenfell fire, many PI insurers have introduced fire risk exclusion clauses, some relating to cladding or to tall buildings but some more comprehensive. Exclusion clauses relating to basement or below ground works have also become common. Some exclusion clauses apply retrospectively, leaving architects’ past clients uninsured. The RIBA obliges architects to hold PII as far as the market allows, so the obligation is not absolute but architects should be clear with their clients on these matters. Contracts between the architect and their insurer involve the usual conditions and most critically that the architect informs their insurer as soon as possible of any ‘circumstance likely to lead to a claim.’ Since this condition is open to wide interpretation, it is helpful for architects to establish a positive advisory relationship with their broker or insurer.

Sustainability, energy saving and green issues in a time of climate emergency Following the IPCC’s report of 2018, Architects Declare was formed in 2019 as a declaration of climate and biodiversity

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emergency aiming to transform the built environment so that it is planned, constructed and operated within planetary boundaries delivering positive social benefits for all. By 2022, there were more than 7000 Architectural Practices signed up worldwide. Architects Declare published their Practice Guide in 2021 to help signatories convert their declaration into meaningful action and build momentum within their practice. https://www.architectsdeclare.com/uploads/AD-PracticeGuide-2021-v1_3.pdf

Architects’ responsibilities Architects have responsibilities to their clients, their building users, the community and the wider world, as well as to their builders and consultants. Excessive resource – and especially energy – consumption and CO2 generation are the most pressing problems facing the world: responsibility for resolving these problems lies most heavily on the industrialised world that has largely created them. Around half the UK’s CO2 emissions are from building and buildings, two-thirds of which are from housing. In July 2015, not unexpectedly, the government abandoned its prior policy that by 2016 all new housing would be built to even higher carbon neutral standards or ‘Level 6’ in the (now defunct) Code for Sustainable Homes. This would have meant that new housing was designed to need virtually no space heating or cooling (equivalent to the Passivhaus standard), and that residual energy use including water heating, cooking, lighting and other appliances was balanced by at least as much ambient energy generated on site, for example by photovoltaic panels or wind turbines. The Code for Sustainable Homes was a voluntary standard for new housing, except for Housing Associations where level 3 was a mandatory requirement, which assessed the standard of the building under 9 criteria: Energy, Waste, Water, Materials, Surface Water Run Off, Management, Pollution, Heath & Wellbeing & Ecology.

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The Code was scrapped by the Government after the Housing Standards Review. However, there are still ‘legacy’ assessments being undertaken whereby, if a condition of Planning was to achieve a certain Code level, and was agreed before 27 March 2015, the Local Authority is likely to require this to be carried out. The Deregulation Act brings in a Clause that will amend the Planning and Energy Act 2008 to prevent local authorities from requiring higher levels of energy efficiency than Building Regulations. This second Clause was due during 2016. A ‘successor’ to CSH has been established by BRE as the Home Quality Mark; this and the AECB Standard are more widely used although their application is purely voluntary and the Deregulation Act is intended to prevent them being imposed on developers. New buildings are only a small fraction of the national stock: although designing new buildings to high standards is vital, the bulk of the problem lies with the poor standards of existing buildings. The vast amount of alteration and refurbishment work represents the major opportunity that most people have to improve the environment and their own future. A number of organisations are researching the most appropriate sustainable refurbishment for old properties. The Energy Saving Trust, BRE and the AECB have produced a number of useful documents covering sustainable refurbishment. However, a note of caution: all refurbishment projects are different, and whilst the guidance is very useful it is just that, guidance, and each project must be treated individually as there are many factors that can affect the approach taken to successfully refurbish an existing building. Constraints on maximising environmental improvements to some existing buildings include poor siting, overshadowing and historic building restrictions; the one advantage that many existing buildings have is substantial thermal mass, increasingly valuable in an age of global warming.

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Passivhaus A building methodology created by the Passivhaus Institut (PHI) founded in Germany in 1996, it is increasing in popularity. The Passivhaus Trust is an organisation that promotes the adoption of Passivhaus in the UK. By 2022, there were at least 60,000 certified Passivhaus buildings worldwide, including individual homes, apartments, offices, schools and community buildings. It provides an extremely low energy building with high levels of user comfort. Significantly, it aims to reduce the performance gap through certification that seeks to ensure that the building is both designed and constructed properly. The level of rigour is unique amongst the standards. It does not rely on bolt-on technologies; however, different Passivhaus classes can be achieved with more renewable energy provision. Whilst certification is the most robust way to ensure the final build meets the required standards, it is possible to adopt the methodology to improve the environmental performance of any building design: in depth knowledge of the methodology is required to do this successfully. The principles of Passivhaus are: • Very high levels of insulation to the building fabric, so for UK climate, a U-value of 0.15W/(m2K) or less. • Extremely high-performance triple-glazed windows and doors with insulated frames, this means a U-value of 0.80 W/(m²K) or less, and shading where required to prevent excessive solar gain. • Airtight building fabric – far better (13 times) than the 2022 Building Regulations requirements, and over 30 times better than typical UK building stock. • ‘Thermal bridge free’ construction – no cold spots to avoid condensation problems. • A ventilation system with heat recovery, allowing for good indoor air quality and energy savings: at least 75% of the heat from the exhaust air is transferred to the incoming fresh air by means of a heat exchanger.

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There are specific performance criteria to be met for a building to be considered a Passive House: 1. The Space Heating Energy Demand is not to exceed 15 kWh/m2 of net living space (treated floor area) per year or 10 W per m2 peak demand. 2. The Renewable Primary Energy Demand (PER, according to PHI method), the total energy to be used for all domestic applications (heating, hot water and domestic electricity) must not exceed 60 kWh per m2 of treated floor area per year for Passive House Classic. 3. Airtightness: a maximum of 0.6 air changes per hour at 50 Pascals pressure (ACH50), as verified with an onsite pressure test (in both pressurised and depressurised states). 4. Thermal comfort must be met for all living areas in summer as well as during winter, with not more than 10% of the hours in a given year over 25°C. Note: Neither embodied energy nor thermal mass is defined by Passivhaus criteria, but both may feature in Passivhaus projects. The above figures are for a new build, there are a number of Passive House classes defining different standards for new build and refurbishment: The Passive House classes are as follows: Passive House, for new buildings: Classic, Plus or Premium depending on the use of renewable energy sources. EnerPHit, for refurbishment of existing buildings, this standard allows a slightly higher energy demand due to the difficulties of retrofit. Classes are Classic, Plus or Premium depending on the use of renewable energy sources. The PHI Low Energy Building Standard, for buildings that do not fully comply with Passive House criteria for various reasons. Refer to www.passivhaus.com and www.passivhaustrust.org. uk for further details.

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Land use planning and transport New development should increase density and integrate uses to minimise transport (which accounts for over 30% of UK CO2); planning and facilities to encourage public transport, electric vehicles and cycle use should be included. Food and biomass production should ideally be allowed for locally. Site layouts should be solar oriented and minimise overshadowing – both for passive heat gain and for solar energy generation.

Landscape design • Direct enhancements of the environmental performance of buildings: shelter planting both for wind breaks and climbers attached to buildings; deciduous planting for seasonal shade (planted pergolas are more controllable than tree planting which may grow to shade solar panels and PVs); planted roofs for micro-climate, insulation and membrane protection; water conservation ponds for reuse and amenity; reed bed sewage treatment; biofuel cropping. • Indirect enhancements in terms of the quality of life and the biosphere: planted roofs, permeable/informal pavings and sustainable drainage systems to minimise flooding; indigenous and site-specific planting; allotments; composting provision; wildlife supportive planting to improve habitats and biodiversity. • Process enhancements to minimise construction damage: thorough landscape surveys followed by enforceable wildlife and planting protection plans; pollution control during construction; high quality and motivated site management to prevent damage and promote landscape protection.

Environmental building design Principal glazed elevations should be oriented south or between SW and SE to maximise useful solar gain passively and actively, without shading or obstruction of low angle winter

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sun but – and this is vital as the climate warms – with adequate secure ventilation and shading against high angle summer sun to prevent overheating; deciduous planting can provide seasonally adjusting shade at low cost. Northerly elevations for housing should have least glazing, though for some building types with high internal heat gains, such as offices, maximising daylight via north lights may be a more effective energy saving measure. New glazing should be to the best standards, for example triple, soft-coat low-e glazing, gas-filled, with thermal-spacers to centre pane U-values below 0.7 Wm2ºC. Window location and design should allow for cross flow and high and low-level ventilation including secure night ventilation to make best use of thermal mass. Housing should be planned to provide principal spaces towards the south and ‘buffer spaces’ – usually service areas that can be heated to a lower temperature – to the north. Super-insulated walling and roofing should be combined with dense internal linings, structure, floors and partitioning to provide appropriate thermal mass. Conservatories, as opposed to garden rooms, can be used effectively as passive solar sunspaces but should not be substituted for basic space; they should be separated by insulated walling and glazing from other parts of the building. If they are heated at all, for frost protection of plants for example, they need to be separately thermostatically controlled so that lower temperatures are maintained; they need to be securely vented at high and low level to prevent overheating in summer and south facing sunspaces will need external shading or solar control glass in addition.

Building services The objective should be to simplify and reduce building services to a minimum.

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Complex services tend to increase both capital and maintenance costs and reduce user satisfaction through a lack of understanding and control. On the other hand, increasingly sophisticated – and intelligible – electronic control systems are getting cheaper so that precisely tailored, localised – yet remotely accessed – and responsive environmental control systems are becoming more prevalent. Where heating or cooling systems are necessary in existing buildings, radiant types such as underfloor water heating pipework tend to be most efficient for the majority of building types, especially high spaces. Local controls, such as thermostatic radiator valves, are important to allow for varying conditions of weather and occupation and to avoid wasted heating; efficiency of existing systems can be improved by more specific control systems allowing for different temperatures in different zones and weather compensation. Air conditioning should not be needed for normal occupation and should be excluded from new building designs wherever possible unless poor local air quality precludes natural ventilation. Ground-tempered air supply fed from areas free from air and noise pollution to MVHR systems may be a viable lower energy alternative. Hot water services should be concentrated around heat sources and storage to minimise heat loss from pipework; wherever possible, hot water should be preheated by solar panels with high capacity super-insulated storage so as to minimise fuel use during summer. Subject to site and planning restrictions, ambient energy generation by photovoltaic, solar thermal or wind turbine should be considered; although Feed in Tariff (FIT) has ceased for PVs and Renewable Heat Incentive (RHI) subsidies have been drastically reduced, reduced equipment costs mean installations can still be viable. Heat recovery from waste hot water is an established and effective technology appropriate at both domestic and commercial scale.

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Where consistent heating, hot water and power is required in larger buildings, combined heat and power (CHP) systems can provide heat and electrical generation simultaneously at high efficiency; especially combined with thermal stores, biofuel boilers using wood pellets, wood chips, straw, logs, etc. are available to very high efficiencies and levels of automation though local fuel availability, potential air pollution and maintenance issues need to be resolved. From 2022, there was a capital subsidy for replacement of fossil fuel boilers with heat pumps – initially via the Clean Heat Grant, then via the Boiler Upgrade Scheme. Ventilation systems are likely to be required because of the very high standards of airtightness required in new buildings; ­humidity-sensitive passive or wind-driven stack systems minimise energy use while powered heat reclaim vent systems (MVHR) at efficiencies up to 90% minimise ventilation heat losses. Daylighting and artificial lighting should be considered together. High levels of daylight will reduce electrical consumption for lighting but glare may need to be controlled; use of horizontal blinds, light shelves, etc. can improve daylighting in deep plan spaces while reducing glare at the perimeter. Artificial lighting should be high efficiency, that is, LED, fluorescent or discharge lamps, and should be locally controlled or daylight/occupancy-sensor controlled in larger buildings. Both light fittings and window glazing need to be regularly cleaned to maintain efficiency. Water consumption should be reduced by use of low water use appliances such as spray, percussive or electronic taps, low flush cisterns, fine spray showers, etc. Where site conditions permit, installation of below ground rainwater cisterns to collect roof drainage for use in WC flushing, external taps, etc., plus washing machine and bathing use if appropriately filtered, can be cost-effective due to savings on both water metering and sewerage charges, though energy use is higher than from mains water. Grey water systems filter and recycle waste water from showers, baths and washing machines and need less tank space but require more maintenance than rainwater systems.

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Materials Environmental concerns should figure prominently alongside issues of function, aesthetics and cost in the selection of materials by architects. The environmental implications of particular materials specification are often complex and it may prove most practical to refer to the guides available such as ‘BRE Green Guide to Specification.’ There are three main areas for environmental consideration: • Embodied energy – the sum of all energy used in the extraction, processing, manufacture and delivery of a material. One of the best known high embodied energy materials is aluminium whose extraction and processing from bauxite requires very high energy input, though recycling and the use of ‘green’ hydro-electric power for smelting immediately complicate the picture. Arguably, embodied energy concerns can be offset in the consideration of energy conservation materials. • Toxicity – toxic pollution arising from extraction, processing and manufacture: toxins emitted in the installation and use of a material; toxins emitted in the decay, demolition and disposal of a material. PVC is probably the most notorious building material in this respect with both its manufacture and disposal at risk of being seriously toxic. Many materials including solvents (paints, preservatives, liquid tanking, etc.) and glues containing formaldehyde (as in chipboard, MDF, etc.) are best known for emitting toxic pollution in application and during occupation of buildings. • Sourcing – the environmental implications of obtaining a material from a particular source or type of supplier. The best publicised issue in this respect is the one regarding unsustainable forestry where the use of timber (generally an environmentally benign material), extracted in a non-­ environmental way, has led to widespread bans on its use without third-party certification. The most respected certifier is the Forestry Stewardship Council (FSC) who have sustained independent probity over many years; the PEFC

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(Programme for Endorsement of Forest Certification) is also worthy of consideration. In virtually all cases, there are more acceptable substitutes for environmentally damaging materials, though in some cases the substitutes may be less widely available or more costly. Some examples are given below: Cement Chipboard, MDF, etc.

Fibreglass/mineral wool Lead sheet roofing Oil-based insulation foams PVC rainwater goods PVC drainage goods PVC roof membranes PVC-sheathed cables PVC windows and doors Rainforest hardwood Solvent-based paints, etc. Timber preservatives Vinyl flooring

Lime in place of cement or cement reduction by PFA in mix Timber/oriented strand board (OSB)/ softwood plywood/vapour-permeable sheathing boards Cellulose fibre/sheep’s wool/flax and hemp/recycled plastic Tin-coated stainless steel or titanium zinc Cork/foamed glass Powder-coated galvanised steel Clayware/polypropylene/polythene/ stainless steel EPDM, TPO, etc. Rubber-sheathed cables Aluclad timber, Accoya and Thermowood FSC-Certified/temperate sourced hardwood Water-based/eco paints No preservative/Boron preservatives Linoleum/natural rubber

In few cases are the substitutes either a perfect substitute or entirely free of adverse environmental consequences; the guides referred to above provide more details. In some cases, there are serious practical disadvantages to the substitutes, for example there are no benign insulants to compare in performance for an equivalent thickness to the high performance petro-chemical foams such as phenolic foam and isocyanurate, which are nearly twice as effective as cellulose fibre or sheep’s wool. Architects and their clients may decide that this is a more environmentally acceptable use of petroleum, rather than as fuel oil or petrol, and that the space saving is worth achieving.

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Finishes Reducing the use of finishes is generally environmentally beneficial: unfinished materials tend to be better quality, less processed, last longer and require less maintenance, thus reducing future environmental burdens; their higher capital cost is quickly offset once cycles of redecoration or renewal are considered. For example, a stone or hardwood finish may cost more than a good quality carpet on a screeded floor but once the carpet requires replacement, the more expensive finish is quickly seen to have been the economic choice. Unfinished materials are easier and more valuable to recycle or reuse since their lack of finishes makes them both easier to inspect and simpler to process. Sources: Green Guide to the Architect’s Job Book (last ­published 2007) RIBA Sustainable Outcomes Guide The RIBA’s 2019 Sustainable Outcomes Guide includes the following useful summary of project design principles: The key design principles that should be followed through all stages of the RIBA Plan of Work 2020 are below, with the emphasis on energy efficiency measures before renewables or offsetting are considered: 1. Prioritise retrofit of existing buildings 2. Prioritise Fabric First principles for building form and envelope 3. Fine tune internal environment with efficient mechanical systems 4. Provide responsive local controls 5. Specify ultra-low energy appliances 6. Specify ultra-low energy IT 7. Prioritise maximum use of onsite renewables appropriate to context

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8. Demonstrate additionality of offsite renewables 9. Offset remaining carbon through a recognised scheme Source: www.architecture.com

Landscaping 1. What Landscape Architects bring to a sustainably designed project 2. Mitigation/adaptation for climate change 3. Guidelines and assessment of sustainability 4. Guidelines for urban tree planting 5. Resources for sustainable urban planting and water management

What Landscape Architects bring to a sustainably designed project Whilst both professions have invaluable contribution to sustainability, a Landscape Architect’s role is principally focused on ecosystems and nature. In any discussion of sustainable design, it’s vital to consider the importance of soil resources and management, water management, ecology and biodiversity as well as plants and plant selection. The Landscape Institute explains that role as follows: Landscape professionals are integral to creating sustainable places. We design with nature, rather than against it, bring a unique, integrated response to the complex and interconnected issues of climate change and biodiversity loss. Our sector is already tackling climate change and biodiversity loss. With more support and stronger regulation for greener development, policymakers can help us continue to deliver critical interventions: • Reducing embodied carbon of outdoor spaces • Implementing energy-saving measures such as living roofs and tree planting, and reducing food miles by

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integrating and maximising local food production in the landscape • Enabling non-vehicular transport by designing for low-carbon travel routes • Using sustainable urban drainage systems to adapt to increasing flooding and coastal erosion • Increasing urban heat resilience by installing green infrastructure, improving the thermal performance of buildings and reducing the ‘urban heat island’ effect Landscape Institute 2022

Mitigation/adaptation for climate change The statement above is obviously a high-level policy statement; for a more considered explanation, refer to the recent Landscape Institute publication “Landscape for 2030.” This document expands on the LI’s 2008 climate change position statement and outlines the techniques for mitigation and adaptation for climate change. It includes useful case studies. Source: https://landscapewpstorage01.blob.core.windows.net/ www-landscapeinstitute-org/2021/04/12510-­ LANDSCAPE-2030_v6.pdf

Guidelines and assessment of sustainability Since the last edition, a wealth of tools for measuring sustainability have emerged. Ranging from standards to guidelines, one of these is the Pathfinder app for Carbon Calculator. Source: https://climatepositivedesign.com/pathfinder/ However, there is less legislative control over ecosystem management. One obvious exception is the recent ­Biodiversity Net Gain requirement. Set to become a mandatory part of planning law in 2023, many local authorities refer to the

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standard already and are already aiming for site biodiversity on new developments to be improved by a minimum of 10%.

Guidelines for urban tree planting Successful establishment of plant material in urban areas relies on a number of factors; knowledge of the site and its constraints, appropriate species selection, supply of healthy plant stock, technical design solutions, thorough specification, and an understanding of the future maintenance and management of the scheme. Architects can contribute to the successful establishment by considering planting as early as possible in the design process. Any decisions on planting should be taken in conjunction with advice from Landscape Architects, recommendations from Tree Officers, Arboriculturalists and other professionals, and with consideration of the growing body of research from organisations such as The Trees and Design Action Group, The Landscape Institute and Forestry Commission. In recent years, problems posed by pests and diseases, coupled with changes to our climate have made the correct tree selection even more important. It is anticipated that hotter, drier summers and wetter, warmer winters will place urban trees under stress, and as the RHS acknowledge “For sites especially vulnerable to summer droughts and waterlogging it is worth choosing trees known to be especially tolerant.” The Landscape Institute, in liaison with DEFRA, (the Department for Environment Food and Rural Affairs) has issued technical papers on both climate change and biosecurity whilst the Trees and Design Action Group (TDAG) has produced “Trees in Hard Landscapes: A Guide for Delivery” 2014. This is an indispensable guide for all professionals involved in selection and provides technical assistance and practical design advice.

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Source: Trees in Hard Landscapes: A Guide for Delivery

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Source: Trees in Hard Landscapes: A Guide for Delivery

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In addition, Tree Selection for Green Infrastructure (TDAG 2019) provides more extensive guidance on selecting appropriate species for a range of contrasting planting scenarios. As well as providing advice on the general approach to species selection, it includes information for over 280 species on their use-potential, size and crown characteristics, natural habitat, environmental tolerance, ornamental qualities, potential issues to be aware of and notable varieties. Source: https://www.tdag.org.uk/uploads/4/2/8/0/4280686/ tdag_treespeciesguidev1.3.pdf

Resources for sustainable urban planting and water management In addition to these comprehensive documents prepared by TDAG, there are many other practical resources available to Architects that can improve the success of urban tree planting and water resource management; structural soils, SUDS, integrated water management systems, etc. There are hosts of companies providing technical data. One particularly useful resource is Green Blue Urban Company whose comprehensive catalogue of online documents includes information cost benefit analysis of urban tree planting, utilities and rootspace, hydraulic modelling, tree pit design, etc. Source: https://greenblue.com/gb/resources/resource-centre/

98

Architect’s Pocket Book

Hedge list (from Readyhedge) Leaves Blue Holly (Ilex mes. ’Heckenfee/ Heckenstar’)

Flowers Growth

E

Barberry (Berberis E or D species)

yes

Prune

Site

Description

medium

July

shade tolerant

blue tinges to the leaves, hardier than normal holly, red berries in winter

medium

July

shade tolerant

dark green, red or yellow leaves, with yellow to orange flowers depending on variety

shade tolerant

dark green leaves trims up tightly, avoid suffruticosa as it grows to slowly

Common Box (Buxus sempervirens)

E

slow

when needed

Common Laurel (Prunus lau. ’Rotundifolia’)

E

fast

June/ August

large leathery green leaves excellent screening plant

Elaeagnus ebbingii

E

fast

June/ August

silver grey foliage, slightly prickly stems

English Yew (Taxus baccata)

E

medium

August

Dark green foliage, shade tolerant, not red berries if left untrimmed wet soil

Escallonia

E

medium

June/ August

sheltered aspect

Golden Privet (Ligustrum oval. ’Aureum’)

SE

fast

when needed

Green Beech (Fagus sylvatica)

D

medium

June/ August

Green Privet (Ligustrum ovalifolium)

SE

fast

when needed

Grisellinia littoralis

E

fast

June/ August

Hawthorn (Crataegus monogyna)

D

fast

June/ August

Holly (Ilex aqu. ’Alaska’)

E

slow

June/ August

yes

small leaved, pink, white or red flowers depending on variety yellow and green leaves, trims up tightly to form a good hedge

wind and chalk tolerant

mid green leaves turning copper coloured in the winter, these leaves then retained till the spring green leaves, trims up tightly to form a good hedge

coastal or sheltered aspect

suitable for milder and coastal areas, has a pale green leaf thorny stems, white flowers in May, excellent field hedge

Shade tolerant

dark green foliage, red berries in the winter months

Design guidance Leaves

Flowers Growth

Prune

Site

99

Description

Hornbeam (Carpinus betulus)

D

fast

June/ August

green leaves turning silver grey in winter, tolerant of all soil types

Japanese Holly (Ilex crenata ’Dark Green’)

E

v slow

when needed

a great replacement for Box, small dark green leaves

Leylandii (Cupressus leylandii)

E

fast

June/ August

fast conifer hedge, excellent for quick screening

Mixed Native Hedge

D

yes

fast

June/ August

A mixture of native species, excellent field hedging

Osmanthus Burkwoodii

E

yes

medium

June/ August

small green leaves with highly scented white flowers in spring

Photinia Red Robin

E

fast

June/ August

bright red new growth in spring fading to green for the winter

Pittosporum tenuifolium

E

medium

June/ August

Portuguese Laurel (Prunus lus. angustifolia)

E

fast

June/ August

Purple or Copper Beech (Fagus syl. Purpurea)

D

medium

June/ August

Shrubby Honeysuckle (Lonicera nitida)

E

fast

when needed

Sweet Bay (Laurus nobilis)

E

slow

June

Western Red Cedar (Thuya pli. ’Gelderland’)

E

fast

June/ August

fast conifer hedge, excellent for quick screening

White Cedar (Thuya occ. ’Brabant’)

E

fast

June/ August

fast conifer hedge, excellent for quick screening

sheltered aspect

silver grey foliage, best in a sheltered area small dark green leaves with red tinged stems, excellent formal hedge

wind and chalk tolerant

Purple leaves turning copper coloured in the winter, these leaves then retained till the spring very small green leaves can be trimmed into a formal hedge

sheltered aspect

dark green leaves, best suited for a sheltered area

100 Architect’s Pocket Book

Tree list (from Hillier Nurseries) NATIVE TREES including long-established introductions – many of which have become naturalized. Size

Species

Common name

M

Acer campestre

Field Maple

L

Acer platanoides

Norway Maple

L

Acer pseudoplatanus

Sycamore

L

Aesculus hippocastanum

Horse Chestnut

S/M

Alnus glutinosa

Common Alder

S/M

Alnus incana

Grey Alder

M

Betula pendula

Silver Birch

M/L

Carpinus betulus

Hornbeam

L

Castanea sativa

Sweet Chestnut

S

Crataegus monogyna

Hawthorn

L

Fagus sylvatica

Beech

L

Fraxinus excelsior

Ash

L

Juglans regia

Walnut

S

Malus sylvestris

Crab Apple

M

Populus tremula

Aspen

M/L

Prunus avium

Wild Cherry or Gean

S/M

Prunus padus

Bird Cherry

L

Quercus cerris

Turkey Oak

I

Quercus ilex

Evergreen or Holm Oak

L

Quercus robur

English Oak

S

Sorbus aria

Whitebeam

S

Sorbus aucuparia

Mountain Ash or Rowan

S

Sorbus intermedia

Swedish Whitebeam

M/L

Tilia cordata

Small-leaved Lime

L

Tilia platyphyllos

Large-leaved Lime

Design guidance 101

Tree list continued TREES FOR NARROW STREETS

and tight areas. Selected for narrow heads or narrowly conical outline. Size

Species

Ornamental features

L

Acer platanoides, ‘Columnare’

Yellow flowers, yellow autumn colour

M/L

Acer platanoides, ‘Crimson Sentry’

Purple leaves

M/L

Alnus cordata

Yellow catkins

M/L

Carpinus betulus, ‘Frans Fontaine’

Tight, columnar form

L

Corylus colurna

Yellow autumn colour

L

Fagus sylvatica, ‘Dawyck’

Golden foliage

L

Fagus sylvatica, ‘Dawyck Gold’

Yellow foliage fading to green

L

Fagus sylvatica, ‘Dawyck Purple’

Purple leaves

S/M

Malus trilobata

Red/purple autumn colour

S/M

Malus tschonoskii

Purple/red/yellow autumn colour

S

Prunus, ‘Amanogawa’

Pink flowers, double

S

Prunus, ‘Ichiyo’

Pink flowers, double

M

Prunus, ‘Sunset Boulevard’

Pink flowers, red autumn colour

S

Prunus sargentil, ‘Rancho’

Pink single flowers, red autumn colour

S

Prunus, ‘Snow Goose’

White flowers, bright green leaves

S

Prunus, ‘Spire’

Single pink flowers, purple/red autumn colour

M

Prunus schmittii

Small pink flowers, attractive bark

M

Pyrus calleryana, ‘Chanticleer’

White flowers, orange/yellow autumn colour

L

Quercus robur, ‘Fastigiata’

S

Sorbus aucuparia, ‘Cardinal Royal’

Dark red fruits

CONIFERS M

Cupressus glabra, ‘Pyramidalis’

S

Cupressus sempervirens

L

Metasequoia glyptostroboides

Blue foliage

Reddish-brown autumn colour

102 Architect’s Pocket Book

Tree list continued TREES FOR HOUSING ESTATES OR SUBURBAN AREAS which have reasonably wide verges. Selected for ornamental value and/or neat, regularly shaped heads. All trees for narrow streets could also be used here. Size

Species

Ornamental features

M

Acer campestre, ‘Streetwise’

Neat head, yellow autumn colour

M

Betula nigra

Shaggy beige bark

M

Betula pendula

White bark

M

Carpinus betulus, ‘Fastigiata’

S

Crataegus laevigate, ‘Paul’s Scarlet’

Double red flowers

S

Crataegus lavallei, ‘Carrieri’

White flowers, orange berries

S

Crataegus prunifolia

White flowers, red fruits, red/yellow autumn colour

S/M

Fraxinus velutina

Grey foliage

S

Malus hupehensis

White flowers, tiny red fruits

S

Malus, ‘Red Profusion’

Purple/red leaves, pink flowers

S

Prunus, ‘Accolade’

Single pink flowers, purple autumn colour

S

Prunus cerasifera, ‘Nigra’

Purple leaves, pink flowers

S

Prunus, ‘Kanzan’

Double pink flowers

S

Prunus, ‘Pandora’

Pink flowers

S

Prunus sargentii

Single pink flowers, orange/red autumn colour

S

Prunus serrula

Shiny mahogany bark

S/M

Prunus, ‘Shirofugen’

Double white flowers

M

Prunus, ‘Sunset Boulevard’

Pink flowers, red autumn colour

S

Prunus subhirtella, ‘Autumnalis’

White flowers winter

S

Prunus subhirtella, ‘Autumnalis Rosea’

Pink flowers winter

S/M

Prunus, ‘Tai-Haku’

Single white flowers

L

Quercus palustris

Red autumn colour

S/M

Robinia pseudacacia, ‘Bessoniana’

Neat round head

S/M

Robinia pseudoacacia, ‘Frisia’

Suffuse yellow foliage

S/M

Sorbus aria, ‘Majestica’

Silver-grey young leaves

S

Sorbus commixta, ‘Embley’

Bright red fruits, orange/red autumn colour

S/M

Sorbus intermedia

Red fruits – occasionally!

S

Sorbus, ‘Sunshine’

Bright yellow fruits

S

Sorbus thuringiaca, ‘Fastigiata’

Red fruits, dense round head

S

Sorbus, ‘White Wax’

White fruits

TREES FOR WIDE ROADS AND AVENUES

Design guidance 103 Generally large trees with a dense canopy. Named cultivars should be chosen where longterm uniformity is desirable, particularly where the seed raised species is characteristically variable (marked V). Size

Species

Ornamental features

L

Acer platanoides V

Yellow flowers, yellow autumn colour

L

Acer platanoides, ‘Crimson King’

Black/purple leaves

L

Acer platanoides, ‘Deborah’ (‘Schwedleri’)

Red/purple young leaves fading to dark green, excellent red/orange/yellow autumn colour

L

Acer platanoides, ‘Emerald Queen’

Yellow flowers, yellow autumn colour

L

Acer pseudoplatanus

Aphids a problem

L

Acer rubrum

Spectacular autumn colour

L

Aesculus x carnea, ‘Briottii’

Red “candles”, produces conkers

L

Aesculus hippocastanum

White “candles”, produces conkers

L

Aesculus indica

Large pink “candles”, orange/yellow autumn colour

M

Betula utilis jacquemontii

Chalk-white bark

M/L

Carpinus betulus V

L

Castanea sativa

L

Fagus sylvatica

Yellow/brown autumn colour

L

Fagus sylvayica, ‘Purpurea’

Purple foliage

M/L

Fraxinus angustifolia, ‘Raywood’

Fine texture, purple autumn colour

L

Fraxinus excelsior V

L

Fraxinus excelsior, ‘Westhof’s Glorie’

M

Fraxinus ornus

L

Juglans nigra

L

Juglans regia

L

Liriodendron tulipfera

L

Platanus hispanica

L

Platanus orientalis

M/L

Prunus avium, ‘Plena’

Double white flowers

M

Prunus padus, ‘Watereri’

White flower spikes

L

Pterocarya fraxinifolia

L

Quercus cerris

L

Quercus frainetto, ‘Hungarian Crown’

L

Quercus ilex

Evergreen

L

Quercus palustris

Red autumn colour

L

Quercus robur

M

Robinia pseudoacacia, ‘Bessoniana’

L

Salix babylonica, ‘Pendula’

White flower spikes

Masses of white flowers

Yellow autumn colour

Disease resistant

104 Architect’s Pocket Book

Tree list continued M

Sorbus thibetica, ‘John Mitchell’

M/L

Tilia cordata V

Large grey leaves

M/L

Tilia cordata, ‘Greenspire’

M

Tilia x euchlora

L

Tilia platyphylios V

M

Tilia platyphylios, ‘Aurea’

L

Tilia platyphylios, ‘Princes Street’

Red twigs in winter, upright

L

Tilia tomentosa, ‘Brabant’

Grey foliage, no aphid problem

No aphid problems

Yellow twigs in winter, upright

“TRANSITIONAL” TREES for linking areas of native planting with urban and suburban development. These trees are primarily cultivars of native/long-introduced trees with particular ornamental characteristics whilst remaining subtle in comparison with, for example, Japanese Cherries. We have also included plants with no native connection, but with a semi-natural “feel”. Size

Species

Ornamental features

M

Acer campestre, ‘Streetwise’

Uniform, candle-flame shaped head

L

Acer platanoides, ‘Emerald Queen’

Uniform head, upright when young broadening with age

L

Acer rubrum

Red/orange autumn colour

L

Aesculus x carnea, ‘Briottii’

Red “candles”

L

Aesculus hippocastanum, ‘Baumannii’

White “candles”, sterile

M/L

Alnus cordata

Greenish-yellow catkins

S

Alnus glutinosa, ‘Imperialis’

Feathery cut-leaf foliage

M

Betula nigra

Shaggy beige bark

M/L

Carpinus betulus

Uniform well-shaped head

L

Corylus colurna

Narrowly pyramidal head, hazel-like leaves and catkins

S

Crataegus prunifolia

White flowers, glossy leaves, red fruits, orange/yellow autumn colour

M/L

Fraxinus angustifolia, ‘Raywood’

Finely textured foliage, purple autumn colour

L

Fraxinus excelsior, ‘Jaspidea’

Yellow shoots, outstanding in winter, butter-yellow autumn colour

L

Fraxinus excelsior, ‘Westhof’s Glorie’

Very uniform round head

M

Fraxinus ornus

Very “Ash”-like but with masses of white flowers in spring

S/M

Fraxinus velutina

Grey foliage

L

Liquidambar styraciflua

Purple/red autumn colour

S/M

Malus hupehensis

White flowers, tiny red fruits

M/L

Prunus avium, ‘Plena’

Double white flowers

M/L

Prunus padus, ‘Watereri’

White flower spikes

Design guidance 105 S

Prunus, ‘Snow Goose’

White flowers, good bright green foliage

M

Pyrus calleryana, ‘Chanticleer’

White flowers, glossy leaves, good autumn colour persisting a long time, upright habit

L

Quercus ilex

Evergreen

S

Sorbus aria, ‘Majestica’

Grey young leaves

S

Sorbus aucuparia, ‘Cardinal Royal’

Dark red fruits

S

Sorbus commixta, ‘Embley’

Orange/red fruits and autumn colour

S

Sorbus, ‘Sunshine’

Yellow fruits

M

Sorbus thibetica, ‘John Mitchell’

Large grey leaves

S

Sorbus, ‘White Wax’

White fruits

M/L

Tilia cordata, ‘Greenspire’

Candle-flame shaped head

M

Tilia x euchlora

Glossy leaves, no aphid problems

L

Tilia platyphyllos, ‘Aurea’

Yellow twigs in winter, upright

L

Tilia platyphyllos, ‘Princes Street’

Red twigs in winter, upright

L

Tilia tomentosa, ‘Brabant’

Grey leaves, no aphid problem

TREES WITH FORMAL ROUND-HEADED HABIT FOR CAR PARKS, ETC. Rarely, if any, problem with aphids. Size

Species

Ornamental features

S

Acer platanoides, ‘Globosum’

Dense head, yellow flowers, orange/ yellow autumn colour

M

Carpinus betulus, ‘Fastigiata’

Dense round head

M

Fraxinus angustifolia, ‘Raywood’

Compact head, feathery foliage, purple autumn colour

S

Prunus, ‘Shogetsu’

Horizontally oval head, double white flowers

S/M

Prunus, ‘Snow Goose’

Broadly columnar head, white flowers

M

Pyrus calleryana, ‘Chanticleer’

Upright, white flowers, good autumn colour

M

Robinia pseudoacacia, ‘Bessoniana’

Dense round head, bright green leaves

S

Sorbus aria, ‘Majestica’

Grey young leaves

S

Sorbus thuringiaca, ‘Fastigiata’

Very dense round head, red fruits

L

Tilia tomentosa, ‘Brabant’

Round head, grey foliage

106 Architect’s Pocket Book

Tree list continued SPECIMEN TREES Trees for use as individual specimens or in small groups for Public Open Spaces, Courtyards, etc. Any of those listed for Wide Roads and Avenues would be suitable, the following list also being useful for this purpose. Size

Species

Ornamental features

S

Acer davidii, ‘George Forrest’ standard or multi-stem

Snakebark, good autumn colour

S

Acer platanoides, ‘Globosum’

Dense, round-headed, orange/yellow autumn colour

L

Acer pseudoplatanus, ‘Brilliantissimum’

Round head, shrimp pink young leaves

L

Acer pseudoplatanus, ‘Nizetti’ leaves

Strikingly variegated

M

Betula nigra standard or multi-stem

Shaggy beige bark

M

Betula pendula standard or multi-stem

White bark

M

Betula utilis jacquemontii standard or multi-stem

Chalk-white bark

L

Catalpa bigmonioides

White/purple flowers, beans in winter

M

Eucalyptus debeuzevillei multi-stem

Silvery-blue leaves, patchwork bark

L

Fagus sylvatica, ‘Dawyck’

Effective in groups of 3 of one colour

L

Fagus sylvatica, ‘Dawyck Purple’

Effective in groups of 3 of one colour

L

Fagus sylvatica, ‘Dawyck Gold’

Effective in groups of 3 of one colour

L

Fraxinus excelsior, ‘Pendula’

Weeping Ash

S

Prunus serrula standard or multi-stem

Shiny mahogany bark

L

Quercus robur, ‘Fastigiata’

Good in groups of 3

L

Salix babylonica, ‘Pendula’

Weeping Willow, disease resistant

M

Tilia x europaea, ‘Wratislaviensia’

Suffuse yellow leaves

DROUGHT TOLERANT TREES Drought tolerance clearly covers the spectrum of subjects ranging from those unable to succeed without a permanent supply of water to those able to withstand arid conditions. The plants listed below are those which in the worst case will show no signs of water stress in an average British summer to those which will positively flourish in the driest periods likely to be encountered in the UK – and probably considerably more severe. The latter marked with * and ** for extreme tolerance.

**

Acer campestre & cvs.

*

Acer negundo & cvs. – not variegated

*

Acer platanoides * cvs. Acer pseudoplatanus & cvs. Acer rubrum & cvs.

Liquidambar spp. Magnolia grandiflora cvs. Malus cvs.

**

Morus spp. Nothofagus spp. (no good on chalk)

Design guidance 107 *

Acer Saccharinum & cvs.

*

**

Ailanthud altissima

**

*

Alnus cordata

*

Alnus japonica

**

Populus spp. – esp. P. alba, P x canescens, P nigra, ‘Italica’

*

Alnus spaethii

*

Prunus cerasifera cvs.

**

Castanea sativa

**

Catalpa spp.

*

Prunus serotine

*

Celtis spp.

**

Pterocarya fraxinifolia

*

Cercidiphyllum japonicum

**

Pyrus spp.

**

Cercis siliquastrum

*

Quercus castanaefolia & cvs.

*

Corylus colurna

*

Quercus cerris

Crataegus spp.

**

Quercus hispanica cvs.

Fagus sylvatica & cvs.

**

Phellodendron amurense Platinus cvs.

Prunus padus & cvs.

Quercus ilex Quercus robur & cvs.

Gleditsia triacathos & cvs. – though does not generally perform well in our martime climate **

Paulownia tomentosa

Hipphophae – tree forms

*

Quercus rubra

Juglans nigra

**

Quercus turneri

Juglans regia

**

Robinia spp. & cvs.

**

Koelreuteria paniculate

**

Sophora japonica & cvs.

*

Laburnum spp.

*

Tilia tomentosa & cvs.

**

Ulmus spp. & cvs.

CONIFERS AS TREES Conifers are generally more drought tolerant than broad-leaved trees since they have evolved with scale- or needle-like leaves for this very reason. The following list is a list of very drought tolerant groups which form trees. Calocedrus Cedrus spp. & cvs. Cupressus Ginkgo Pinus Sequoiadendron Taxus Thuja, esp. plicata

108 Architect’s Pocket Book

Anthropometric data Standing Dimensions given are the average for British men and women. They include an allowance for clothing and shoes.

Design guidance 109

Sitting Dimensions given are the average for British men and women. They include an allowance for clothing and shoes.

110 Architect’s Pocket Book

Wheelchair

Design guidance

Wheelchair access Entrance lobbies and corridors – not in dwellings

111

112 Architect’s Pocket Book

Furniture and fittings data

Design guidance

113

114 Architect’s Pocket Book

Kitchen

Design guidance

115

116 Architect’s Pocket Book

Dining room

Design guidance

117

118 Architect’s Pocket Book

Bedroom Bedroom 1800 1500 1350

1900

750

2000

double bed sizes

single bed sizes

1250

minimum space between beds with room for small table cot - 1000 (h)

minimum space needed at sides and ends for making bed 450

450

750

space around beds

650

750

750

600

1900

900

bedside table

Design guidance

119

120 Architect’s Pocket Book

Bathroom 700

min. clear access beside bath

+2200 min ceiling ht +2100 top of shower rail

+1150 c/l mixer

+1250 c/l mixer +1050 grab rail

+0140 bottom of bath +0000 FFL

+0150 top of tray +0000 FFL

700

800

standard bath

1350

short bath

850

900

minimum shower size All measurements in mm

1700

shower / bath

walk-in shower

800

900

large shower 800

900

800

750

750

800

1700

1350

750

corner bath

double-ended bath

1200

1800

long bath

1700

1500

700

1700

800

min clear access beside shower

+2200 min. ceiling ht +2100 top of shower rail

standard shower tray sizes

1000

700

Design guidance

121

122 Architect’s Pocket Book

Laundry and utility Recycling and refuse Laundry and utility 600

700

minimum access from front

1000

1100

850

1720

minimum access from side

580

600

580

600

800

washing machine, dryer and other appliances 1350

650

minimum space for use of board

840

400 150

300

ironing board

Recycling and refuse Bins and Boxes 555

580 480

740 +2370 with lid open +1700 with lid open

+1750 with lid open

+1100 with lid closed

+1100 with lid closed

+0000 ffl 140L wheeled bin flr space required = 680 x 750

+1370 with lid closed

+0000 ffl 240L wheeled bin flr space required = 780 x 940

+0000 ffl 1100 L eurobin flr space required = 1280 x 1085

Design guidance 123

Hall and shed

124 Architect’s Pocket Book

Domestic garages 3000

6000

6000

6000

2400 3m x 6m minimum garage size accepted by planners as a viable parking space

Vehicles and bicycles Home electric vehicle charging Power rating

Average installation Time to full charge cost in 2022 of 60.4kW

2.3 kW (3 pin socket) 3.6 kW 7 kW (to comply with Building Regulations AD S) 22 kW (3phase supply required)

Existing £800 £950

Over 18 hours 17 hours 9 hours

£1200

3 hours

Building Regulations Approved Document S sets out the requirements for Infrastructure for the charging of electric vehicles. The installation of a home charging point can provide an annual average saving of £180. There are many models available and can be fitted on a garage, external wall or driveway.

Design guidance 125

If home charging isn’t possible, then the number of publicly accessible charging points is increasing. Trailing a cable across a public footpath is illegal under the Highways Act 1980 due to obstruction. Vehicle sizes and parking bays Type of bay

Dimensions in mm

Normal Parent and child Disabled On street parallel parking

4800 long × 2400 wide 4800 long × 3200 wide 4800 long × 3600 wide 1800 wide, no length stipulated

Modern cars are up to 53% larger than original models and can often overhang designated bays. www.theaa.com Turning circles

730mm overhang

3810

50 31

7910

Fire appliance

350mm overhang

80 23

2180

Avg saloon car

1720

5780

Car

2690

126 Architect’s Pocket Book

Bicycle parking

Sanitary provision for public buildings Summary of minimum facilities All new public buildings should have separate male and female toilets. Gender-neutral facilities mean men and women share the same space for waiting and hand wash facilities. Unisex – or universal – toilets are dedicated, self-contained toilets that maintain privacy for the single user. Generally, washbasins should be provided in equal numbers to WCs with one for every five urinals. In most public buildings, a minimum of two WCs should be provided so that one may act as a reserve if the other is out of order.

Design guidance 127

Disabled toilets Where there is space for only one toilet in a building, it should be a wheelchair accessible unisex toilet, wide enough to accommodate a standing height wash basin. At least one wheelchair accessible WC should be provided at each location in a building where sanitary facilities are provided. At least one WC cubicle should be provided in separate sex toilet accommodation for use by ambulant disabled people. In addition, where there are four or more WC cubicles in separate sex toilet accommodation, one of these should be an enlarged cubicle for use by people who need extra space.

Workplace Minimum scale of provision of sanitary appliances for staff toilets in offices, shops, factories and other non-domestic premises used as place of work is necessary. Number of toilets and washbasins – mixed use or women only Number of people at work

Number of toilets

Number of washbasins (whb)

1–5 6–15 16–30 31–45 46–60 61–75 76–90 91–100

1 2 3 4 5 6 7 8

1 2 3 4 5 6 7 8

Above 100 persons: 8wc plus 1wc, and whb for every unit or fraction of a unit of 25 persons.

128 Architect’s Pocket Book

Number of toilets and washbasins – men only Number of men at work

Number of toilets

Number of urinals

Number of wash hand basins (whb)

1–15 16–30 31–45 46–60 61–75 76–90 91–100

1 2 2 3 3 4 4

1 1 2 2 3 3 4

1 2 2 3 3 4 4

Above 100 persons: 4wc plus 1wc, urinal and whb for every unit or fraction of a unit of 50 persons.

Sports and entertainment venues Minimum provision of sanitary appliances for assembly buildings where most toilet use is during intervals. For example, theatres, cinemas, concert halls, sports stadiums and similar buildings. Sanitary appliance

Male visitors

Female visitors

WC

About 2 for up to 250 males; plus 1 for every additional 250 males or part thereof

Urinal

About 2 for up to 50 males; plus 1 for every additional 50 males or part thereof About 1 per WC and in addition, 1 per 5 urinals or part thereof

About 2 for up to 20 females; plus 1 for every additional 20 females or part thereof up to 500 females; and 1 per 25 females or part thereof over 500 females N/A

Wash hand basins (whb)

About 1, plus 1 per 2 WCs or part thereof

Source: www.washroomcubicles.co.uk including tables for other building types; British Standard 6465-1:2006+A1:2009 – Sanitary Installations. Note – These are minimum requirements as outlined by British Standards. We fully recommend consulting your local planning office and Building Control for further details.

Design guidance 129

WC compartments for disabled people Wheelchair user

Sanitary dispenser

Alternative door position

1500mm x 1500mm wheelchair turning space

Disposable bin Shelf

2200mm min.

Mirror

Wall A

Finger rinse basin

Clothes hooks

Vertical grab rail

Wall mounted grab rail

600mm

Alarm pull cord Drop-down rail

250mm

Sanitary disposal unit

150mm

Alternative position for alarm pull cord

320mm

500mm

Zone for shelf for standing users

970mm

Vertical grab rail 1000mm min.

1500mm min. (excluding any projecting heat emitters)

Alarm pull cord with two red bangles one at 100mm, the other at 800mm to 1000mm above floor level

SD PT

TP AR

680mm

Disposal bin

480mm*

Shelf

100mm

800-1000mm

720-740mm

HD

Wall A *Height subject to manufacturing tolerance of WC pan HD: Possible position for automatic hand dryer SD: Soap dispenser PT: Paper towel dispenser AR: Alarm reset button TP: Toilet paper dispenser Height of drop-down rails to be the same as the other horizontal grab rails

1100mm

Location of shelf at 950mm above floor level

Sanitary dispenser with coin slot between 750mm and 1000mm above the floor

300mm 300mm

Grab rails

130 Architect’s Pocket Book

Ambulant disabled user and wheelchair accessible shower room

3 Structures A good working relationship is essential between an architect and a structural engineer. In very rough terms, an architect says what a building looks like and the structural engineer makes sure it doesn’t fall down! There should be a feeling of a team with both working to the same aim. An architect needs to appreciate the structural challenges that the scheme imposes. An engineer needs to appreciate the architect’s requirement for form and function. In this mix the building services requirements also need to be considered. The best buildings are a result of collaborative design between the architect, structural engineer and mechanical and electrical engineers. Throughout this, the need to provide the client with what they want and within the budget available needs to be considered. In the UK design of structural elements should be carried out following the suite of Eurocode design codes. Eurocodes follow the ultimate limit state (ULS) design philosophy. In ULS design, partial safety factors are applied to the permanent (dead) and variable (live) loads to be carried by a structure. The design uses these factored loads with defined material properties to determine if a structural element is sufficient. Unfactored loads are used when calculating deflection of the structural element. D ­ eflections caused by both permanent and variable load are checked and deflection limits are typically set according to the surface finishes the structure supports to ensure they are not damaged by the deflection. The structural Eurocodes are Europe-wide structural design codes for building and civil engineering works. Eurocodes are designed to create a unified approach throughout Europe with regard to construction design. Each Eurocode has a corresponding National Annex document. This documents and clarifies laws or standards applicable to each particular country. DOI: 10.4324/9781003357995-3

132 Architect’s Pocket Book

Eurocodes Eurocode 0 Eurocode 1 Eurocode 2 Eurocode 3 Eurocode 4 Eurocode 5 Eurocode 6 Eurocode 7 Eurocode 8 Eurocode 9

Basis of structural design Actions on structures Design of concrete structures Design of steel structures Design of composite steel and concrete structure Design of timber structures Design of masonry structures Geotechnical structures Design of structures for earthquake resistance Design of aluminium structures

EN1990 EN1991 EN1992 EN1993 EN1994 EN1995 EN1996 EN1997 EN1998 EN1999

Examples later in this chapter are given using Eurocodes Information in this chapter is given for guidance only and should give an indication of the size of structural members required to assist with developing a scheme. All structural elements should be checked by a qualified Chartered Structural Engineer for Building Regulation and construction purposes. Consultation with a Chartered Structural Engineer is advised at an early design stage to ensure structural feasibility of the proposals. During structural design, vertical as well as horizontal loads are considered. Horizontal (lateral) loads are largely caused by wind. To resist these shear walls, cross bracing or moment frames (framing with rigid connections at beam/column junctions) are required. A structural engineer will be able to advise which is most suitable, but at scheme design stage, it is important to remember that these elements will need to be accommodated in the building.

Structures 133

Building loading Permanent (dead) and variable (live) loads used in structural design are listed in the Eurocodes. Common permanent loads are contained in Annex A of BS EN 1991-1-1. However, the now withdrawn BS648 is also a good source of material weights and is still relevant and widely used. For material weights of less common or composite materials, trade literature should be referred to. Variable loads are contained in the National Annex to BS EN 1991-1-1.

Engineering units Structural engineering uses newton as its main unit of force. The newton is derived from the unit of mass through the relationship that force is equal to mass times the gravitational pull of 9.81 metres per second per second (9.81 m/s2), in the direction of the force, for example, 1 kilogram f = 9.81 newtons. For approximate purposes, 100 kg = 1 kN. Alternatively, one newton is that force which, if applied to a mass of one kilogram, gives that mass an acceleration of one metre per second per second (1 m/s2) in the direction of the force, so 1 N = 1 kg × 1 m/s2. When calculating the weight of materials for structures, the kilograms should be multiplied by 9.81 to get the equivalent figure in newtons (or 9.81÷1000 for kN). For practical purposes, multiply by 10! As a general rule, the following expressions are used: Superimposed loads Mass loads Stress Bending moment Shear

kN/m2 kg/m2 or kg/m3 N/mm2 kNm kN

1 N/mm 1 N/mm2 1 kNm

= 1 kN/m = 1 x 103 kN/m2 = 1 x 106 Nmm

134 Architect’s Pocket Book

Weights of materials taken from BS648 Material

Description

Aluminium Aluminium roofing Asphalt roofing Ballast Bituminous felt roofing Blockboard Blockwork

Cast Longstrip With vapour barrier Loose, graded 3 layers + vapour barrier Sheet High strength Aerated Lightweight Foundation Cast Blue Engineering Sand/cement London stock Fletton Sheet

Brass Brickwork

Calcium silicate board Cement Concrete Concreting ballast Chalk Chipboard Chippings Clay Copper Copper roofing Cork Cork insulation Cork flooring Felt Glass Glass wool Gravel Hardboard Hardboard

Quantity of unit 0.8 mm 20 mm

kg/m2

3.70 47.00 11.10

18 mm 100 mm 100 mm 100 mm 255 mm

10.50 220.00 64.00 58.00 197.00

115 mm 115 mm 115 mm 115 mm

276.60 250.00 240.00 212.00

6 mm

5.80

2770 1600

8425 2405 2165 2085 1845 1795 1440 2400

Reinforced 2% steel Plain Flooring grade C4 Furniture grade C1A Flat roof finish Undisturbed Cast Longstrip Granulated Board Tiles Roofing underlay Clear float Clear float Clear float Quilt Loose Standard Medium

kg/m3

18 mm 18 mm

13.25 11.75

1 layer

4.75

0.6 mm

5.70

50 mm 3.2 mm 4 mm 6 mm 10 mm 100 mm

6.50 3.00 1.30 10.00 15.00 25.00 1.02

3.2 mm 6.4 mm

2.35 3.70

2300 1760 2125

1925 8730 80

1600

Structures 135

Material

Description

Hardwood

Greenheart Oak Iroko, teak Mahogany Boards Cast Cast

Hardwood flooring Iron Lead

Lime Linoleum MDF Mortar Partitions

Parquet Paving Patent glazing

Pea shingle Perspex Plaster

Plasterboard Plywood Polystyrene PVC roofing Quarry tiles Roofing tiles

Sheet Sheet Lump Quick Sheet Sheet Lime Plastered brick Plastered block p/b and skim on timber studs Flooring Concrete Alum. bars @ 600 mm c/c Alum. bars @ 600 mm c/c Corrugated sheets Lightweight – 2 coat Hardwall – 2 coat Lath and plaster Gyproc wallboard Plaster skimcoat Sheet Expanded, sheet Single ply membrane Laid in mortar Clay – plain

Quantity of unit

kg/m2

23 mm

16.10

Code 4 Code 7

20.40 35.72

3.2 mm 18 mm

4.50 13.80

115 + 25 mm 100 + 25 mm 100 + 25 mm

250.00 190.00 120.00

15 mm 50 mm Single

7.00 122.00 19.00

Double

35.00

13 mm

4.90 10.20

13 mm 9.5 mm 3 mm 6 mm 50 mm 2 mm

12.5 mm 100 mm gauge Clay – single pantile 315 mm gauge Concrete – double 343 mm gauge roman Concrete – flat slate 355 mm gauge Rubber stud flooring Tiles 4 mm

11.60 29.30 9.00 2.20 4.10 0.75 2.50 32.00 77.00 42.00 45.00 51.00 5.90

kg/m3 1040 720 660 530 7205 11 322 705 880 1680

1500

136 Architect’s Pocket Book

Weights of materials – continued Material

Description

Sand Sarking Scalpings Screed Shingle Shingles

Dry Felt

Slate Slate roofing Snow Softboard Softwood Softwood flooring Soil Stainless steel roofing Steel Stone

Stone chippings Tarmac Thatch Terrazzo Timber Vinyl flooring Water Weatherboarding Woodwool Zinc Zinc roofing

Cement/sand Coarse, graded, dry Roof, untreated Tanalised Slab Best Medium strong Heaviest Fresh Wet, compact Sheet Pitch pine, yew Spruce Western red cedar Boards Loose Compact Longstrip Mild Sheet Slate Marble Granite York Bath Including battens Paving See hardwood; softwood Tiles Softwood Slabs Cast Longstrip

Quantity of unit

kg/m2

1.30 50 mm

108.00

95 mm gauge 95 mm gauge 25 mm 4 mm 5 mm 6 mm

8.09 16.19 70.80 31.00 35.00 40.00

12.5 mm

14.45

22 mm

12.20

0.4 mm

4.00

1.3 mm

10.20

25 mm 300 mm 16 mm

53.70 41.50 34.20

2 mm

4.00

19 mm 25 mm 50 mm

7.30 8.55 36.60

0.8 mm

5.70

kg/m3 1600 2000 1842

96 320 670 450 390 1440 2080 7848 2840 2720 2660 2400 2100 1760

1000

6838

A7

A4 A5 A6

A3

A2

Areas for domestic and A1 residential activities

A

Balconies in hotels and motels

All usages within self-contained dwelling units. Communal areas (incl. kitchens) in blocks of flats with limited use – i.e. not more than 3 storeys with not more than 4 self-contained units per floor Bedrooms and dormitories other than A1 or A3 Bedrooms in hotels and motels; hospital wards; toilet areas Billiard/snooker rooms Balconies to A1 Balconies in hostels, guest houses, residential clubs, and communal areas in blocks of flats not covered in A1

Example

Specific use

Category

Imposed floor loads (to BS EN1991-1-1:2002 and UK national annex)

2.0 2.5 Same as the room to which they give access but with a minimum of 3.0 Same as the room to which they give access but with a minimum of 4.0

2.0

1.5

1.5

Distributed load (kN/m2)*

2.7 2.0 2.0 (concentrated at the outer edge) 2.0 (concentrated at the outer edge)

2.0

2.0

2.0

Concentrated load (kN) *

Structures 137

Specific use

Office areas

Areas where people may congregate (with the exception of areas defined under category A, B, and D)

Category

B

C

C3

C2

B1 B2 C1

General use other than in B2 At or below ground floor level Areas with tables, etc. C11 Public, institutional and communal dining rooms and lounges, cafes and restaurants, but not where area might be subjected to physical activities or overcrowding. See C4 or C5 C12 Reading rooms with no book storage C13 Class room Areas with fixed seats C21 Assembly area with fixed seating C22 Places of worship Areas without obstacles for moving people C31 Corridors, hallways, aisles in institutional type buildings not subjected to crowds or wheeled vehicles, hostels, guest houses, residential clubs, and communal areas in blocks of flats not covered in A1

Example

3.0

3.0

3.0

4.5

3.6 2.7

4.0

2.5

4.0 3.0

3.0

2.7 2.7

Concentrated load (kN) *

2.0

2.5 3.0

Distributed load (kN/m2)*

138 Architect’s Pocket Book

C36

C35

C34

C33

C32

Stairs, landing in institutional type building not subjected to crowds or wheeled vehicles, hostels, guest houses, residential clubs and communal areas in blocks of flats not covered in A1 Corridors, hallways, aisles in all buildings not covered by C31 and C32, including hotels and motels and institutional buildings subjected to crowds Corridors, hallways, aisles in all buildings not covered by C31 and C32, including hotels and motels and institutional buildings subjected to wheeled vehicles, including trolleys Stairs, landings in all buildings not covered by C31 and C32, including hotels and motels and institutional buildings subjected to crowds Walkways – Light duty (access suitable for one person, walkway width approx 600 mm) 3.0

4.0

5.0

4.0

3.0

2.0

4.0

4.5

4.5

4.0

Structures 139

Specific use

Shopping areas

Storage and industrial use

Category

D

E

D1 D2 E1

C5

C4

Walkways – General duty (regular two-way pedestrian traffic) C38 Walkways – Heavy duty (highdensity pedestrian traffic including escape routes) C39 Museum floors and art galleries for exhibition purposes Area with possible physical activities C41 Dance halls and studios, gymnasia, stages C42 Drill halls and drill rooms Areas susceptible to large crowds C51 Assembly areas without fixed seating, concert halls, bars and places of worship C52 Stages in public assembly areas Areas in general shops Areas in department stores Areas susceptible to accumulation of goods, including access areas E11 General areas for static equipment not specified elsewhere (institutional and public buildings)

C37

Example

1.8

4.5 3.6 3.6

7.5 4.0 4.0

2.0

3.6

5.0

7.0

5.0

4.5

4.0

3.6

4.5

7.5

5.0

3.6

Concentrated load (kN) *

5.0

Distributed load (kN/m2)*

140 Architect’s Pocket Book

E2

Cold Storage

Paper storage for printing plants and stationery stores Dense mobile stacking (books) on mobile trolleys, in public and institutional buildings Dense mobile stacking (books) on mobile trucks, in warehouses

Reading room with book storage, e.g. libraries General storage other than those specified (liaise with client to determine more specific loads values than the minimum given in this table File rooms, filing and storage space (offices) Stack rooms (books)

Industrial use

E19

E18

E17

E16

E15

E14

E13

E12

4.5

7.0

4.5

2.4 per m of storage 7.0 height but with a minimum of 6.5 4.0 per m of storage 9.0 height 4.8 per m of storage 7.0 height but with a minimum of 9.6 4.8 per m of storage 7.0 height but with a minimum of 15.0 5.0 per m of storage 9.0 height but with a minimum of 15.0 To be determined for specific use

5.0

2.4 per m of storage height

4.0

Structures

141

Traffic and parking areas for light vehicles (≤ 30kN gross vehicle weight) Traffic and parking areas for light vehicles (>30kN, gross vehicle weight≤ 160kN)

F

Access routes; delivery zones; zones accessible to fire engines (≤ 160kN gross vehicle weight)

Garages: parking areas, parking halls

Example

* Whichever produces the greater stress or deflection.

G

Specific use

Category

5.0

2.5

Distributed load (kN/m2)*

To be determined for specific use

10

Concentrated load (kN) *

142 Architect’s Pocket Book

Structures 143

Imposed roof loads (to BS EN1991-1-1:2002 and UK national annex) Roof type

Comments

Distributed Concentrated load (kN/m2)* load (kN)*

All roofs

Where access is needed in addition to that needed for cleaning and repair Where no access is needed except for cleaning and repair Where no access is needed except for cleaning and repair

Same as loads for areas accessing roof

Flat roofs and sloping roofs up to 30° Roof slopes between 30° and 60° (a°) measured on plan Roof slopes 60° 0 or more

0.6 or

0.9

0.6 (60−a)/30 or

0.9

0

0.9

*Whichever produces the greater stress.

Where access is needed for cleaning and repair, these loads assume spreader boards will be used during work on fragile roofs.

Snow loads The snow loading is a function of location, altitude and roof pitch. For buildings with parapets, valleys or changes in roof level, there can be local accumulation of snow from drifting. Drifting snow loads can be significant. See BS EN 1991-1-3 and UK National Annex for further guidance.

Wind loads Wind loading is dependent on many factors such as location, elevation, topography as well as the height and plan dimensions of the building. Consult a chartered structural engineer and see BS EN1991-1-4 and UK National Annex for further guidance.

144 Architect’s Pocket Book

Bending moments and beam formulae Type of beam

Loading diagram

Maximum bending moment

Maximum shear

Freely supported with central load

WL 4

W 2

dc =

WL3 48El

Freely supported with distributed load Freely supported with triangular load Fixed both ends with central load

WL 8

W 2

dc =

5WL3 384El

WL 6

W 2

dc =

WL3 60El

WL 8

W 2

dc =

WL3 192El

Fixed both ends with distributed load One end fixed, the other end freely supported with distributed load Cantilever with end load

WL 12

W 2

dc =

WL3 384El

WL

W

Cantilever with distributed load

WL 2

W

W =  total load

WL 8

↓

L = length E =  modulus of elasticity I =  moment of inertia S =  shear

SA =

5W 8

SB =

3W 8

Maximum deflection d

d=

at × = 0.38 L

dB =

WL3 3El

dB =

WL3 8El

=  point load =  distributed load

↑

WL3 185El

=  free support =  fixed support.

Structures 145

Fire resistance For simple buildings, the level of fire resistance is defined in the Approved Document B of the Building Regulations. For larger and more complex buildings, the advice of a fire engineer should be sought. Approved Document B is regularly updated and the fire resistances given below should be checked against the latest version of Approved Document Part B.

Minimum periods of fire resistance(1) for elements of structure (minutes) Building type

Basement storey

Ground and upper storeys

Depth (m) of the lowest basement

Height (m) of top floor above ground, in a building or separated part of a building

more up than 10 to 10

up to 5

up to 11

up to 18

up to 30

more than 30

Residential i) Houses ii) Flats and maisonettes

n/a Without sprinklers With sprinklers(3)

iii) Institutional iv) Other residential

30*†

30†

60 (5)

†

+§

60 (5)

n/a(4)

60 60

30 30a

60 60+§

X 60+§

X 90+

X(2) 120+

90

60

30†

60

60

90

120‡

60

†

60

60

90

120‡

†

30

(2)

n/a(4)

90 90 90

(2)

90 60

60 60

30 30†

60 30†

60 30†

90 60

X(6) 120‡

90 60

60 60

60 30†

60 60

60 60

90 60

X(6) 120‡

90 60

60 60

60 30†

60 60

60 60

90 60

X(6) 120‡

120 90

90 60

60 30†

90 60

90 60

120 60

X(6) 120‡

Storage and Other Without sprinklers 120 non-residential 90 With sprinklers(3)

90 60

60 30†

90 60

90 60

120 90

X(6) 120‡

Offices

Without sprinklers With sprinklers(3)

Shops and Commercial

Without sprinklers

Assembly and recreational

Without sprinklers

Industrial

Without sprinklers

With sprinklers

(3)

With sprinklers(3) With sprinklers(3)

Car parks for light vehicles

Open sided park(7) n/a Any other park

90

n/a 60

15†# 15†#(8) 15†# (8) 15†# (8) 60 30† 60 60 90 120‡

NOTES For single-storey buildings, the periods under the heading ‘Up to 5’ apply. If singlestorey buildings have basements, for the basement storeys the period appropriate to their depth applies.

146 Architect’s Pocket Book X Not Permitted * For the floor over a basement or, if there is more than one basement, the floor over the topmost basement, the higher of the period for the basement storey and the period for the ground or upper storey applies. † For compartment walls that separate buildings, the period is increased to a minimum of 60 minutes. + For any floor that does not contribute to the support of the building within a flat of more than one storey, the period is reduced to 30 minutes. § For flat conversions, refer to paragraphs 6.5 to 6.7 in Approved Document B Volume 1 regarding the acceptability of 30 minutes. ‡ For elements that do not form part of the structural frame, the period is reduced to 90 minutes. # For elements that protect the means of escape, the period is increased to 30 minutes. 1 Refer to note 1, Table B3 in approved Document B Volume 1 for the specific provisions of test. 2 Blocks of flats with a top storey more than 11 m above ground level (see Diagram D6 in approved Document B Volume 1) should be fitted with a sprinkler system in accordance with Appendix E.

NOTE: Sprinklers should be provided within the individual flats, they do not need to be provided in the common areas such as stairs, corridors or landings when these areas are fire sterile. 3 With sprinkler system’ means that the building is fitted throughout with an automatic sprinkler system in accordance with Appendix E of Approved D ­ ocument B Volume 1. 4 Very large (with a top storey more than 18 m above ground level or with a 10 m deep basement) or unusual dwellinghouses are outside the scope of the guidance provided with regard to dwellinghouses. 5 A minimum of 30 minutes in the case of three storey dwellinghouses, increased to 60 minutes minimum for compartment walls separating buildings. 6 Buildings within the ‘office,’ ‘shop and commercial,’ ‘assembly and recreation,’ ‘industrial’ and ‘storage and other non-residential’ (except car parks for light vehicles) purpose groups (purpose groups 3 to 7(a)) require sprinklers where there is a top storey more than 30 m above ground level. 7 The car park should comply with the relevant provisions in the guidance on requirement B3, Section 11 of Approved Document B Volume 2. 8 For the purposes of meeting the Building Regulations, the following types of steel elements are deemed to have satisfied the minimum period of fire resistance of 15 minutes when tested to the European test method.

i.     Beams supporting concrete floors, maximum Hp/A=230m−1 operating under full design load. ii.    Free-standing columns, maximum Hp/A=180m−1 operating under full design load. iii. Wind bracing and struts, maximum Hp/A=210m−1 operating under full design load. Guidance is also available in BS EN 1993-1-2.

Source: Building Regulations Approved Document B (amd 2022) vol 1 – Table B4.

Structures 147

Low carbon design The embodied carbon of buildings is becoming increasingly important. While in-use carbon emissions are still important, great progress has been made in reducing the in-use energy and as a result embodied carbon is now the more dominant source of carbon. Architects (and structural engineers) are in a position to reduce the embodied carbon in buildings through the choice of constructing a new building or reusing an existing building and the construction materials specified. Embodied carbon is measured as the kg of carbon dioxide (CO2) per square metre of floor area (kgCO2 /m2). The chart below shows typical embodied carbon in the superstructure of different types of structural systems. The numbers have been calculated following the Institution of Structural Engineers Structural Carbon Tool. The figures given are for stages A1 to A5, which represents material production and processing from cradle to gate (i.e. until the point it is loaded onto transport to go to a construction site).

148 Architect’s Pocket Book

Superstructure embodied carbon A1–A5 without sequestration

As the chart shows reusing a building is the most effective way of reducing the embodied carbon in your project. Even with layout changes and significant upgrading of an existing building to improve thermal performance, the embodied carbon is likely to be lower than constructing a new building.

Structures 149

Substructure (Foundations) The type of foundation required is dependent upon a number of factors. Soil type, topography, building type and size and proximity of trees (both existing and planned) all need to be considered. For low rise residential buildings, simple trial holes can sometimes be sufficient to determine the depth to a suitable bearing level. For sites with more complex topography and ground conditions and for larger buildings, a more detailed ground investigation by a ground investigation consultant will be required.

Trees and foundations If the founding material contains clay and there are trees ­(existing or proposed) close by it will be necessary to determine the potential for shrinkage/swelling of the clay content (as the trees affect the moisture content of the clay) and compare this with the height and variety of trees. If trees are going to impact the moisture content of the clay soil around the foundations, then this needs to be designed against and this can increase the depth of the foundations significantly. To determine the potential for shrinkage, samples of the founding material need to be taken, sealed in a plastic bag to retain the natural moisture, and sent to a soils laboratory for testing. The laboratory would assess the % of fine particles (clay and silt) in the sample, the moisture content, liquid and plastic limits and the plasticity index (PI). The higher the PI, the higher the risk of shrinkage/swelling with variations of moisture content. Ground that is liable to swell following removal of existing trees can damage foundations and measures to protect footings and slab need to be put in hand. The use of a compressible layer against the face of the foundations is usual, as is provision of a void below a suspended ground slab.

150 Architect’s Pocket Book

An experienced engineer will be able to advise on the type of foundations and any protection measures required. Guidance is given in the NHBC Standards – Part 4.2 Foundations –­B ­ uilding near Trees.

Simple strip/trench fill foundations This style of foundation is suitable for depths up to 2.5 m (subject to stability of the sides of the excavations). It is recommended that trench fill be used for foundations deeper than a metre so that the concrete level for laying blocks is high enough not to require protection against collapse of the excavation sides.

Piled foundations This style of foundation is suitable for building on filled or soft ground or ground requiring deep foundations to overcome the problems of swelling/shrinkage. Detailed site investigations are required to determine the ground conditions at depth and are best undertaken by a specialist geotechnical firm. The piles are used to support reinforced ground beams and/or slab.

Raft foundations Rafts are used when the ground conditions are such that strip footings would need to be very wide or there is high risk of settlement. The raft distributes the loads over a very large area. It is essential that the ground conditions are uniform under the raft to eliminate the risk of differential settlement. It is necessary to ensure services entering or leaving have a flexible connection – such as rocker pipe in the foul drains.

Reducing embodied carbon in foundations Concrete is widely used for foundations, particularly on smallscale domestic projects due to its familiarity, ease of use and cost. However, there are alternatives that have lower embodied

Structures

151

carbon and if concrete is used, there are ways to reduce its environmental impact. Lower embodied carbon options include the use of stone, timber and proprietary screw piles. Stone-filled trenches can be used as a way of reducing the volume of concrete used in a trench fill foundation. Stone is compacted into the base of the trench before being capped with a reinforced concrete capping beam. The additional embodied carbon of the steel reinforcement is outweighed by the significant reduction in the volume of concrete used. Timber sleepers can be used to spread the load into the ground. Typically, they are used in multiple layers at ground level for lightweight structures. Settlement can be more significant when founding at ground level and the ground can be subject to larger changes in volume due to moisture levels and can be affected by freezing. Therefore, it is important to consider if differential settlements will be an issue with your structure. Timber piles can also be used to support larger loads. However, when using timber in damp locations such as the ground, design life must be considered. Timber foundations are therefore only likely to be suitable for temporary structures or those with a short design life. Screw piles are steel tubes with a diameter between 60 and 90 mm which have screw threads on the outside. They can be screwed into the ground using handheld or digger mounted drivers. Screw piles are capable of supporting relatively high loads. They are joined at their head by steel or concrete beams to allow construction of a building above. If there is no alternative to using concrete foundations, a more detailed site investigation to accurately determine the soil properties can help reduce the amount of concrete required by allowing the design to be catered for the specific ground conditions rather than a worst case. All of these alternatives require the input of a chartered engineer to determine their suitability based on the site conditions.

152 Architect’s Pocket Book

Safe loads on subsoils (BS 8004: 2015) Presumed allowable bearing values under static loading Subsoil

Type

Bearing (kN/m2)

Rocks

Strong igneous and gneissic rocks in sound condition Strong limestones and sandstones Schists and slates Strong shales, mudstones and siltstones Dense gravel, dense sand and gravel Medium dense gravel, medium dense sand and gravel Loose gravel, loose sand and gravel Compact sand Medium dense sand Loose sand Very stiff boulder clays, hard clays Stiff clays Firm clays Soft clays and silts

10,000

Non-cohesive soils

Cohesive soils

4000 3000 2000 > 600 < 200–600 < 200 > 300 100–200 < 100 300–600 150–300 75–150 < 75

Notes: 1. These values are for preliminary design only. Foundations always require site investigation first. 2. No values are given for very soft clays and silts; peat and organic soils; made up or filled ground as presumably these would be thought unsuitable for any building. 3. Values for rocks assume that foundations are carried down to unweathered rock. 4. Widths of foundations for non-cohesive soils to be not less than one metre. 5. Cohesive soils are susceptible to long-term settlement. 6. Generally, foundations should not be less than 1.0–1.3 m depth to allow for soil swell or shrink, frost and vegetation attack.

Structures 153

Superstructure (above ground structure) Superstructure refers to all of the structural elements above ground. Typically in the UK masonry, timber, steel and concrete are the main superstructure materials. The majority of existing residential buildings in the UK are masonry construction. Increasingly, timber is being used for residential construction and for low-rise non-residential buildings such as schools, workplaces and even theatres. Steel and concrete tend to be used in larger commercial buildings where increased strength is needed to accommodate large spans or medium to high rise. Superstructure is discussed in the following sections by m ­ aterial type.

154 Architect’s Pocket Book

Masonry structures Masonry refers to any form of brick, block or stone construction where units are stacked together typically with a mortar between to bond the individual units. Masonry structural solutions for small buildings include: - Insulated cavity walling: traditional cavity walls with masonry inner and outer leaves tied together with wall ties and with full or partial insulation. - Insulated solid walling: usually aerated concrete or hollow clay block walling with external or internal insulation in addition. Structural masonry is designed to Eurocode 6 BS EN 1996-1-2. Masonry walling relies on the mortar between individual blocks or bricks to provide some degree of bond between them, distribute loading and provide continuity in the wall. Traditional masonry design requires relatively small window and door openings to ensure sufficient masonry is provided between to resist vertical and wind loading. If larger openings, glazed corners and cantilevers are required, then additional steel or concrete beams and posts are typically used alongside the masonry in a hybrid structural system. Long panels of masonry may need stiffening with wind posts within the wall construction in order to resist lateral loads.

Structures 155

Timber floors and roofs need to be tied to masonry walls to provide the walls with lateral stability against wind loads. At floors, L-shaped galvanised steel straps are used fixed to the joists and hooked over the inner leaf of masonry. Typically, straps should be at 1.2m c/c. At roof level, vertical restraint straps are required to hold the roof down to the walls as well as providing lateral support to the top of the wall. Typically, L-shaped galvanised steel straps are fixed to the timber wall plate and down the inside of the masonry wall. Rafters or flat roof joists are in turn fixed to the timber wall plate. In cavity construction, wall ties are required to ensure the inner and outer leaves of masonry work together structurally. Wall ties are typically made from galvanised steel, stainless steel or low thermal conductivity fibre composites. When lime mortars are used galvanised ties must not be used. Typical wall tie spacings are shown in Figure 3.2.

Source: www.leviat.com

156 Architect’s Pocket Book

Structures 157

Load-bearing masonry buildings often have relatively high embodied carbon. However, there are increasing numbers of lower embodied carbon concrete blocks available which can reduce the embodied carbon of the walls. Movement joints may be required to control thermal movement and shrinkage. As a general rule, movement joints should be at 6 m centres in blockwork and 12 m in clay brickwork. These joints need to be supported laterally by wind posts or return walls. The use of lime mortars increases the flexibility of masonry construction and can reduce the need for movement joints. While lime mortars are weaker than cement mortars, they are typically more than strong enough for most two- and three-storey domestic buildings.

Preliminary masonry design checks Slenderness ratio of load bearing brickwork and blockwork walls The slenderness ratio involves the thickness and height and the conditions of support to the top and bottom of a wall, pier or column. It is defined as effective height ÷ effective thickness. It should not be greater than 27 when subjected to mainly vertical loading. Effective height of walls When the floor or roof spans at right angles to the wall with sufficient bearing and anchorage: effective height = actual height between centres of supports

158 Architect’s Pocket Book

For concrete floors bearing centrally onto a wall, irrespective of the direction of span: effective height =

3

4

of actual height

For floors or roof spanning parallel with wall without bearing (but wall restrained to floor/roof plane with lateral restraint straps): effective height = actual height For freestanding walls with no lateral support at top: effective height = 2 times actual height Effective thickness of walls For solid walls: effective thickness = actual thickness For cavity walls: effective thickness = 3 t13 + t23 where t1 and t2 are the thickness of each leaf of the wall. So for a 100 mm outer leaf, 100 mm cavity, 100 mm inner leaf wall, the effective thickness is = 3 1003 + 1003 = 126 mm. For more information, see Building Regulation Approved D ­ ocument A.

Structures 159

Lintels for masonry construction There are many suppliers of lintels, both precast concrete and pressed steel. Generally, precast concrete lintels are used where there is a lower visual requirement as they will either be exposed and on show or will need to concealed behind plaster. Pressed steel lintels are designed such that once the wall is built, you will not see the lintel on the face of the wall and are therefore good for facing brickwork and stone where no plaster or render will be applied. Lintel selector guides are available on the websites for various manufacturers. You will need to know the thickness of the inner and outer leaves, the width of the cavity, clear span and loads to be carried. The following is just a small example of what is available on the web. It is advisable to check the websites periodically as the products are revised: Precast concrete lintels Precast concrete lintels come as standard, high strength or fair faced. Fair faced are cast to higher standard for uses where they will be left exposed. From some suppliers, it is also possible to get stone-coloured lintels. Examples from a supplier are shown below.

www.supremeconcrete.co.uk. Information is correct at time of going to print.

Supreme concrete precast concrete lintels

160 Architect’s Pocket Book

Structures

161

Pressed steel lintels Pressed steel lintels are available for cavity and single leaf walls. Lintels are made from galvanised steel with polyester powder corrosion-resisting coating. Different profiles are available to cater for different inner and outer leaf thickness and cavity thickness. “Thermally broken” lintels are also available to reduce thermal bridging across the cavity. Alternatively, separate inner and outer leaf lintels can be used. Catnic steel lintels

162 Architect’s Pocket Book

Images courtesy of Catnic 2022 www.catnic.com/lintels

Other profiles Combined boot or ‘top-hat’ lintels support inner and outer leaves. Most architects prefer not to use combined lintels as there is a serious issue of thermal bridging. Rebated combined lintels – for window/door frames set back in reveals. Lintels for closed eaves – for windows tight under sloping roofs. Lintels for walls with masonry outer skin and timber frame inside. Lintels for masonry outer skin where inner skin is carried by concrete lintel. Lintels for internal partitions and load-bearing walls. Special profiles for various styles of arches and cantilevered masonry corners.

Structures 163

Timber construction Timber construction covers several construction techniques: - Load-bearing studwork construction - Timber posts and beams (natural timber or glulam) - Cross-laminated timber (CLT) All forms for timber construction require the timber to be kept at a minimum of 150 mm above external ground level to protect against damage from moisture. Typically, a blockwork or reinforced concrete upstand is provided on top of the foundations onto which the timber construction is fixed. Timber construction can be quick during the site stage of construction. The speed is dependent upon the degree of prefabrication, but where prefabricated studwork panels or CLT are used, a two-storey house can have the main load-bearing construction erected in a matter of days. Structural timber is designed to Eurocode 5 BS EN 1995-1-1.

Load-bearing studwork Load-bearing studwork construction uses softwood vertical studs and horizontal rails. Racking resistance (resistance to lateral wind loads) is provided by a wood-based panel sheathing such as OSB or plywood. At openings, such as doors and windows, the vertical loads are carried by timber lintels over the opening and through additional supports, known as cripple studs at each end of the lintel. Weather resistance is provided by external cladding. The cladding is non-load bearing, but does transfer wind loads into the load-bearing timber frame beyond. Cladding can be provided by timber boarding, masonry or other cladding panel systems. A ventilation gap is required between the cladding and timber frame. Brick or stone cladding is erected as a separate skin, linked to the timber frame studs by stainless steel wall ties. Differential movement is likely to occur between the timber frame and brick or block cladding and the design detailing must make

164 Architect’s Pocket Book

allowance for this. Tile and timber cladding is fixed on timber battens fixed through to the studs of the wall panels. Window and door frames are fixed to the timber frame, not into the cladding. Thermal insulation is usually incorporated in the spaces between the studs and as a complete layer over the outside or inside of the load-bearing frame. Generally, flexible insulation materials are better suited between the studs and they can be fitted snugly between studs whereas rigid insulation often results in gaps between the studs and insulation, which reduces thermal performance. Breather membranes and vapour control membranes may be required, depending on the design of the wall. Load-bearing stud construction can either be site built or the wall panels can be factory-produced. Factory production brings quality benefits. The size and degree of prefabrication varies between: Open panels comprising studs, rails, sheathing and an external breather membrane. The thermal insulation, internal vapour control membrane (where needed) and lining are all installed on site. Closed panels as above but with insulation, protective membranes, linings, external joinery and sometimes even services, already installed. Additional layers of insulation and board materials are added to provide higher levels of sound insulation and additional fire protection where required, for example, party walls between houses and party walls between flats. Ground floors can be constructed from concrete or timber and will be influenced by the ground conditions. Intermediate floors are of timber joists, either solid or engineered timber I joists depending upon the span required. Like walls, floor panels can be factory produced. The joists or prefabricated panels are usually installed on top of the wall panels and provide a platform from which to build subsequent storeys. Roofs can be pitched or flat. Constructed from timber rafters or trussed rafters. As with walls and floors, panels can be factory produced. Many other types of roofing are also suitable.

Structures 165

Timber post and beam This form of construction uses timber posts and beams to form a structural frame that carries all of the vertical and lateral loads. Cross bracing or shear walls are required to resist wind (lateral) loads. While the posts and beams will be cut to length and connections formed in the factory, unlike load-bearing studwork, full prefabrication is not typically possible. It is possible to make the posts and beams from solid timber (commonly oak) or glulam timber sections. Timber floors and roofs are constructed in a similar way to those used in load-bearing studwork with timber joisted floors and timber rafters forming roofs. Often the rafters will be supported on timber ridge beams and purlins. In this form of construction, the internal and external walls are non-load bearing and are only required to transfer lateral wind loads into the main timber frame. Cladding options and the requirement for breather and vapour control membranes are the same as those for load-bearing studwork.

Cross-laminated timber (CLT) CLT is formed by laminating planks of sawn timber together in layers to form solid timber panels. Panels can be up to 22 m long and 3.5 m wide and are produced in thicknesses ranging from 60 mm up to 300 mm. CLT panels are the load-bearing structure providing vertical and lateral load resistance. Walls, floors and roofs can all be formed from CLT. The panels are all cut to size in the factory and delivered to site on flat bed lorries. Erection is by crane and the panels are fixed together with large screws at regular centres along the joints. Provided they are appropriately positioned, window and door openings can simply be cut in the CLT in the factory and no additional lintels are required. Cladding options and the requirement for breather and vapour control membranes are the same as those for load-bearing studwork.

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Timber (BS EN 338–2016 Structural timber – Strength classes – Properties of timber to EC5) Strength classes for softwood based on edgewise bending tests – strength, stiffness and density values C14

C16

C18

Strength properties in N/mm2 Bending 14 16 18 Tension 7.2 8.5 10 parallel Tension 0.4 0.4 0.4 perpendicular Compression 16 17 18 parallel Compression 2.0 2.2 2.2 perpendicular Shear 3.0 3.2 3.4 Stiffness properties (kN/mm2) Mean 7.0 8.0 9.0 modulus of elasticity parallel bending Density (kg/m3) Mean density 350 370 380

C20 C22 C24 C27 C30 C35 C40

20 22 11.5 13

24 27 30 14.5 16.5 19

35 40 22.5 26

0.4

0.4

0.4

0.4

0.4

0.4

0.4

19

20

21

22

24

25

27

2.3

 2.4 2.5

2.5

2.7

2.7

2.8

3.6

3.8

4.0

4.0

4.0

4.0

4.0

9.5

10.0 11.0 11.5 12.0 13.0 14.0

400

410

420

430

460

470

480

NOTE: 1 Values given above for tension strength, compression strength, shear strength, char. modulus of elasticity in bending, mean modulus of elasticity perpendicular to grain and mean shear modulus have been calculated using the equations given in EN 384. 2 The tension strength values are conservatively estimated since grading is done for bending strength. 3 The tabulated properties are compatible with timber at moisture content consistent with a temperature of 20°C and a relative humidity of 65%, which corresponds to a moisture content of 12% for most species. 4 Characteristic values for shear strength are given for timber without fissures, according to EN 408. 5 These classes may also be used for hardwood with similar strength and density profiles such as poplar or chestnut. 6 The edgewise bending strength may also be used in the case of flatwise bending.

Structures 167

Strength classes for hardwood based on edgewise bending tests – strength, stiffness and density values D18

D24

D27

Strength properties in N/mm2 Bending 18 24 27 Tension 11 14 16 parallel Tension 0.6 0.6 0.6 perpendicular Compression 18 21 22 parallel Compression 4.8 4.9 5.1 perpendicular Shear 3.5 3.7 3.8 Stiffness properties (kN/mm2) Mean  9.5 10 10.5 modulus of elasticity parallel bending Density (kg/m3) Mean density 570 580 610

D30

D35

D40

D50

D60

D70

30 18

35 21

40 24

50 30

60 36

70 42

0.6

0.6

0.6

0.6

0.6

0.6

24

25

27

30

33

36

5.3

5.4

5.5

6.2

10.5

12.0

3.9

4.1

4.2

4.5

4.8

5.0

11.0

12.0

13.0

14.0

17.0

20.0

640

650

660

740

840

960

NOTE: 1 Values given above for tension strength, compression strength, shear strength, char. modulus of elasticity in bending, mean modulus of elasticity perpendicular to grain and mean shear modulus, have been calculated using the equations given in EN 384. 2 The tabulated properties are compatible with timber at moisture content consistent with a temperature of 20°C and a relative humidity of 65%, which corresponds to a moisture content of 12% for most species. 3 Characteristic values for shear strength are given for timber without fissures, according to EN 408. 4 The edgewise bending strength may also be used in the case of flatwise bending.

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Preliminary sizing of timber beams Rectangular timber beam formula (uniformly distributed load) 1. Obtain the total imposed and dead loading for the beam (W) in kN. 2. Select a strength class of timber to define bending stress (s) in N/mm2 and modulus of elasticity (E) in N/mm2. 3. Choose breadth of beam (b) in mm. 4. Calculate the maximum bending moment (M) in kNm. Check stress (s): M=

WL 8

M= σZ, and Z= ∴ M=σ

bd2 6

bd2 6M or bd2 = 6 σ

hence d =

WL × 6 × 106 8×b× σ

Check deflection (d): For spans up to 5.04 m, maximum deflection allowable is span/360. Above 5.04m deflection is limited to 14mm for domestic floors. δ = L × 0.003 =

hence d =

5WL3 bd3 , and I = 384EI 6

WL2 × 52.08 × 103 E×b

The depth of the section to use will be the greater of those calculated for stress or deflection.

Structures 169

Where: b = breadth of beam, mm d = depth of beam, mm f = flexural stress, N/mm2 L = clear span, m M = bending moment, kNm W = total load, kN Z = section modulus, mm3 I = second moment of area, mm4 E = modulus of elasticity, N/mm2

Timber floor joists Spans below are from BM TRADA Eurocode 5 span tables for solid timber members in floors, ceilings and roofs for dwellings, 4th edition. For further timber section sizes, see further span tables available from BM TRADA.

Permissible clear spans for C16 grade softwood (m) Dead load (kN/m2) Joist centres (mm)

< 0.25 400

Joist size (b × d) (mm)

0.25 to 0.50

600

400

600

0.50 to 1.25 400

600

Maximum clear span (m)

47 × 97 47 × 120 47 × 145 47 × 170 47 × 195 47 × 220

1.89* 2.48* 2.99* 3.50* 4.00* 4.51*

1.54 2.08 2.61 3.05 3.49 3.94

1.76* 2.33* 2.82* 3.30* 3.78* 4.25*

1.45 1.94 2.45 2.87 3.29 3.71

1.53 1.98 2.46 2.88 3.30 3.72

1.27 1.66 2.09 2.50 2.86 3.23

75 × 120 75 × 145 75 × 170 75 × 195 75 × 220

2.96* 3.56* 4.16* 4.75* 5.34*

2.59 3.12 3.65 4.17 4.70

2.79* 3.37* 3.93* 4.49* 5.05*

2.44 2.94 3.44 3.94 4.43

2.45 2.95 3.45 3.95 4.45

2.09 2.57 3.01 3.45 3.88

*  Two additional joists required. Bold text = normal bearing of 40 mm to be doubled.

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Permissible clear spans for C24 grade softwood (m) Dead load (kN/m2) Joist centres (mm)

< 0.25 400

Joist size (b × d) (mm)

0.25 to 0.50

600

400

600

0.50 to 1.25 400

600

Maximum Clear Span (m)

47 × 97 47 × 120 47 × 145 47 × 170 47 × 195 47 × 220

2.26* 2.83* 3.40* 3.98* 4.55* 5.12*

1.87 2.47 2.97 3.48 3.98 4.48

2.10* 2.67* 3.21* 3.76* 4.30* 4.83*

1.74 2.31 2.80 3.28 3.75 4.23

1.80 2.32 2.81 3.29 3.77 4.24

1.51 1.96 2.44 2.86 3.27 3.69

75 × 120 75 × 145 75 × 170 75 × 195 75 × 220

3.29* 3.96* 4.62* 5.27* 5.92*

2.88 3.48 4.06 4.64 5.22

2.79* 3.37* 3.93* 4.49* 5.05*

2.44 2.94 3.44 3.94 4.43

2.45 2.95 3.45 3.95 4.45

2.09 2.57 3.01 3.45 3.88

*Two additional joists required. Bold text = normal bearing of 40 mm to be doubled. Dead loads exclude the self-weight of the joist. The table allows for an imposed load of not more than 1.5 kN/m2 and a concentrated load of 0.9 kN, but not for concentrated loads from trimmers, partitions, etc. All joists beneath a bath should be doubled.

Floor decking (See NHBC standards 6.4 – D14) Joist centres (mm)

400

450

600

Thickness of decking (mm) T & G softwood boarding Chipboard Plywood Oriented strand board (OSB)

16 18 12 15

16 18 12 15

19 22 16 18/19

Note: Oriented strand board should be laid with the stronger axis at right angles to the support.

171

Structures

Timber ceiling joists Spans below are from BM TRADA Eurocode 5 span tables for solid timber members in floors, ceilings and roofs for dwellings, 4th edition. For further timber section sizes see further span tables available from BM TRADA. Permissible clear spans for C16 grade softwood (m) Dead load (kN/m2) Joist centres (mm)

< 0.25 400

Joist sizes (b × d) (mm)

600

0.25 to 0.50 400

600

Maximum Clear Span (m)

38 × 72 38 × 95 38 × 120 38 × 145 38 × 170 38 × 195 38 × 220

1.11 1.64 2.25 2.89 3.53 4.18 4.84

1.07 1.57 2.14 2.72 3.31 3.90 4.50

1.06 1.55 2.11 2.67 3.25 3.83 4.41

1.01 1.46 1.97 2.48 3.00 3.52 4.04

47 × 72 47 × 95 47 × 120 47 × 145 47 × 170 47 × 195 47 × 220

1.24 1.82 2.48 3.16 3.86 4.55 5.25

1.19 1.74 2.35 2.97 3.61 4.24 4.88

1.18 1.71 2.31 2.92 3.54 4.16 4.78

1.12 1.61 2.15 2.71 3.26 3.82 4.38

Permissible clear spans for C24 grade softwood (m) Dead load (kN/m2) Joist centres (mm)

< 0.25 400

Joist sizes (b × d) (mm) 38 × 72 38 × 95 38 × 120 38 × 145

600

0.25 to 0.50 400

600

Maximum clear span (m) 1.30 1.91 2.60 3.32

1.26 1.82 2.46 3.11

1.24 1.80 2.42 3.06

1.18 1.69 2.25 2.83

172 Architect’s Pocket Book Joist sizes (b × d) (mm)

Maximum clear span (m)

38 × 170 38 × 195 38 × 220

4.04 4.77 5.50

3.77 4.44 5.10

3.70 4.35 5.00

3.41 3.99 4.57

47 × 72 47 × 95 47 × 120 47 × 145 47 × 170 47 × 195 47 × 220

1.45 2.11 2.86 3.62 4.40 5.17 5.94

1.39 2.00 2.69 3.40 4.10 4.81 5.51

1.37 1.98 2.65 3.34 4.03 4.71 5.40

1.30 1.85 2.46 3.08 3.70 4.32 4.94

The table allows for an imposed load of not more than 0.25 kN/m2 and a concentrated load of 0.9kN. No account has been taken for other loads such as water tanks or trimming around chimneys, hatches, etc. Minimum bearing for ceiling joists should be 35 mm.

Holes through joists Typical spacing rules for small diameter holes through timber floor and ceiling joists for small water pipes and cables are shown in Figure 3.6. For larger holes or holes outside the parameters shown, a chartered structural engineer should be consulted.

Engineered joists and beams Engineered timber joists are made from a softwood timber top and bottom chord with an OSB or lightweight steel web. They

Structures 173

allow for increased spans and reduced shrinkage in timber floor structures as well as more efficient use of material; their higher cost means they compete with sawn timber only on larger spans and larger projects; typical savings in cross section area for a given joist depth as compared with sawn C24 softwood would be 20–30%. The steel web versions also allow for easy distribution of services through floors. Parallel-strand lumber (PSL) is a form of engineered wood made from parallel wood strands bonded together with adhesive. PSL has vastly improved permissible stress and modulus of elasticity compared with sawn timber allowing increases in span on equivalent section of C24 softwood in the order of 50%. Safe load information can be found on published trade literature. Both engineered joists and PSL are manufactured under various trade names that you can find by searching for engineered joists or PSL on your internet browser.

Prefabricated timber trusses For simple rectangular roofs with flat ceilings at eaves level, a prefabricated roof is the easiest solution. Trusses are design and erected by a truss manufacture. The inner leaf of the cavity wall is used to support the trusses. Trusses are generally at 600 mm centres, and there is a nominal allowance for access into the ceiling void. The internal arrangement of timbers makes it hard to store items in the loft space. Access should be restricted to maintenance (such as dealing with cables, plumbing, etc.). An allowance for water tanks is generally made. More complicated shapes such as intersecting roofs can be achieved, as well as hip ends. Multiple trusses are used to support monopitch trusses forming the hips. Trusses incorporating accommodation can be fabricated. These are known as attic trusses. However, existing roofs are complicated to modify to create additional accommodation, requiring the insertion of new structure

174 Architect’s Pocket Book

such as purlins to allow the cutting away of internal props as well as trimming for stairs access. Modifying existing prefabricated roofs is to be avoided and consideration should be given to a new roof structure. For further information, see http://www.tra.org.uk (The Trussed Rafter Association).

Glulam timber beams Glulam beams are engineered beams made from planed sections of timber, glued together under pressure. Generally, these laminations are 45 mm deep by varying widths. The minimum depth is 4 laminations (i.e. 180 mm) and typical widths are 65, 90, 115, 140, 165 and 190 mm. The range of standard Glulam sections varies depending on manufacturer. Sections outside the standard range can be manufactured, as can curved sections, but both would be more expensive. Glulam beams are of the order of 18% stronger than standard timber. The following is a selection of the permissible loads on Glulam beams for use in floors for preliminary sizing only.

Maximum uniformly distributed load in kN/m, deflection limited to 14mm Glulam section h × w (mm)

Clear span (m) 3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

65 × 315 90 × 315 90 × 360 90 × 405 115 × 405 115 × 450 115 × 495 160 × 495 160 × 540

9.1 12.7 16.1 19.9 25.4 27.3 27.3 38.0 38.0

6.7 9.4 11.9 14.7 18.8 23.2 23.5 32.7 32.7

5.2 7.2 9.1 11.3 14.4 17.9 20.5 28.7 28.6

4.1 5.7 7.2 8.9 11.4 14.1 16.8 23.4 25.4

2.8 3.9 5.8 7.2 9.2 11.4 13.6 19.0 22.3

1.9 2.7 4.0 5.6 7.2 9.4 11.3 15.7 18.4

1.3 1.9 2.8 4.0 5.1 7.0 9.2 12.8 15.5

0.9 1.3 2.0 2.9 3.7 5.1 6.7 9.4 12.1

Structures 175

Metal structural framing systems (SFS) This form of construction is suited to larger scale residential developments such as flats or apartments. The structural system is similar to load-bearing timber studwork, but instead of using timber, cold-formed lightweight steel studs and a mineral based sheathing board are used. Cold-formed lightweight steel floor joists and flat roof joists can also be used. Panels can be prefabricated in the factory and craned into position on site. Many manufacturers have their own trade names for their load-bearing SFS systems. Cold-formed structural steel is designed to Eurocode 3 BS EN 1993-1-3.

176 Architect’s Pocket Book

Steel frame Steel frame construction is suited to larger commercial, healthcare and education buildings. Steel columns, beams and cross bracing form a structural frame that carry the vertical and lateral loads. There are numerous options for floor and roof construction including precast concrete planks and permanent metal formwork with cast concrete. For a lower embodied carbon construction, CLT can be used for floor and roof decks. Structural steel is designed to Eurocode 3 BS EN 1993-1-1.

Steelwork The most commonly used sections in construction are Universal Beams (UB) and Universal Columns (UC). Both are ‘I’ shape in section with UBs being taller than they are wide and UCs having the same height and width. UBs are typically used as beams and UCs typically as columns. There are no simple span tables for steel beams, but for early scheme design, a simple rule of thumb of the span divided by 20 can be applied to establish the approximate beam depth that will be required. If space is allowed for the closest section size that is greater than this depth from the list of common sizes below this should give you sufficient space for structure.

Structures 177

Common Universal Beam (UB) sizes Section

Weight (kg per m)

Depth (mm)

Width (mm)

152 × 89 × 16 178 × 102 × 19 203 × 102 × 23 203 × 133 × 25 203 × 133 × 30 254 × 102 × 22 254 × 102 × 25 254 × 102 × 28 254 × 146 × 31 254 × 146 × 37 254 × 146 × 43 305 × 102 × 25 305 × 102 × 28 305 × 102 × 33 305 × 127 × 37 305 × 127 × 42 305 × 127 × 48 305 × 165 × 40 305 × 165 × 46 305 × 165 × 54 356 × 127 × 33 356 × 127 × 39 356 × 171 × 45 356 × 171 × 51 356 × 171 × 57 356 × 171 × 67 406 × 140 × 39 406 × 140 × 46

16 19 23 25 30 22 25 28 31 37 43 25 28 33 37 42 48 40 46 54 33 39 45 51 57 67 39 46

152 178 203 203 207 254 257 260 251 256 260 305 309 313 304 307 310 304 307 311 349 353 352 356 359 364 402 402

 89 102 102 133 134 102 102 102 146 146 147 102 102 102 123 124 125 165 166 167 125 126 171 172 172 173 142 142

Source: Interactive Blue Book, SteelConstruction.info.

Common Universal Column (UC) sizes Section 152 × 152 × 23 152 × 152 × 30 152 × 152 × 37 203 × 203 × 46 203 × 203 × 52 203 × 203 × 60 203 × 203 × 71 203 × 203 × 86

Weight (kg per m) 23 30 37 46 52 60 71 86

Depth (mm)

Width (mm)

152 158 162 203 206 210 216 222

152 153 155 203 204 205 206 209

178 Architect’s Pocket Book Section

Weight (kg per m)

Depth (mm)

Width (mm)

254 × 254 × 73 254 × 254 × 89 254 x 254 x 107 254 × 254 × 132 254 × 254 × 167 305 × 305 × 97 305 × 305 × 118 305 × 305 × 137 305 × 305 × 158 305 × 305 × 198 305 × 305 × 240 305 × 305 × 283

73 89 107 132 167 97 118 137 158 198 240 283

254 260 267 276 289 308 315 320 327 339 352 365

254 256 258 261 265 305 307 309 310 314 317 321

Source: Interactive Blue Book, SteelConstruction.info.

Steel hollow sections Due to their geometric properties, steel hollow sections have very good compression capacity and torsion resistance. Hence, they are commonly used for columns, bracing and situations where the load will twist a beam along its length. They are more expensive than open steel sections (UB, UC, channels, angles). Steel hollow sections can be either rolled hot or cold in the steel mill. This results in different structural properties. Hollow sections are manufactured as square, rectangular and circular profiles:

SHS = structural hollow section CHS = circular hollow section RHS = rectangular hollow sections including square sections Hot formed structural hollow sections are manufactured to BS EN 10210-1:2006. The square and rectangular sections have tight corner radii that have higher geometric properties and therefore a higher load-carrying capacity in compression than cold-formed sections.

Structures 179

Cold-formed hollow sections are manufactured to BS EN 10219-1:2006 The square and rectangular sections have larger corner radii that give lower geometric properties than hot-formed sections of the same size and thickness. Cold-formed hollow sections must NOT be substituted in a direct size-for-size basis for hotformed hollow sections without checking the design. Where structural properties are not critical, cold formed provide a cheaper solution.

Structural steel hollow sections External sizes in mm. Wall thicknesses vary. Hot formed Circular

21.3 26.9 33.7 42.4 48.3 60.3 76.1 88.9 101.6 114.3 139.7 168.3 193.7 219.1 244.5 273.0 323.9 355.6 406.4 457.0

Square

40 × 40 50 × 50 60 × 60 70 × 70 80 × 80 90 × 90 100 × 100 120 × 120 140 × 140 150 × 150 160 × 160 180 × 180 200 × 200 250 × 250 260 × 260 300 × 300 350 × 350 400 × 400

Cold formed

Rectangular Circular

50 × 30 60 × 40 80 × 40 90 × 50 100 × 50 100 × 60 120 × 60 120 × 80 150 × 100 160 × 80 180 × 60 180 × 100 200 × 100 200 × 120 200 × 150 220 × 120 250 × 100 250 × 150 260 × 140 300 × 100

33.7 42.4 48.3 60.3 76.1 88.9 114.3 139.7 168.3 193.7 219.1 244.5 273.0 323.9 355.6 406.4 457.0 508.0

Square

25 × 25 30 × 30 40 × 40 50 × 50 60 × 60 70 × 70 80 × 80 90 × 90 100 × 100 120 × 120 140 × 140 150 × 150 160 × 160 180 × 180 200 × 200 250 × 250 300 × 300 350 × 350 400 × 400

Rectangular

50 × 25 50 × 30 60 × 40 70 × 40 70 × 50 80 × 40 80 × 50 80 × 60 90 × 50 100 × 40 100 × 50 100 × 60 100 × 80 120 × 40 120 × 60 120 × 80 140 × 80 150 × 100 160 × 80 180 × 80

180 Architect’s Pocket Book Hot formed Circular

508.0

Square

Cold formed

Rectangular Circular

Square

300 × 150 300 × 200 300 × 250 340 × 100 350 × 150 350 × 250 400 × 150 400 × 200 400 × 300 450 × 250 500 × 200 500 × 300

Rectangular

180 × 100 200 × 100 200 × 120 200 × 150 250 × 150 300 × 100 300 × 200 400 × 200 450 × 250 500 × 300

Source: Interactive Blue Book, SteelConstruction.info.

Thermal breaks in steelwork Whenever steelwork passes through the thermal insulation line, it is preferable to include a thermal break to minimise thermal bridging. Common situations where external structure is supported off structure within the building are at external canopies and cantilever balconies. The cantilevering beam has to cross through the insulation and can become a thermal bridge. This thermal bridging can be avoided by detailing an end plate moment connection within the cantilevering beam at the line of the building’s insulation. Steel-to-steel interfaces would need to be isolated with a thermal break plate. The connection works the same way as a steel to steel moment connection with the tension forces resisted by the bolts.

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The compression forces are transmitted through the thermal break material. Thermal break washers under the steel washers to the bolt further reduce the thermal bridging. See the following for a typical moment connection incorporating a thermal break. More sophisticated thermal break connections are available from suppliers such as Farret and Schöck. THERMAL BREAK PLATE

THERMAL BREAK WASHERS

PLAN

OUTSIDE

INSIDE

TENSION BOLTS

CANTILEVER BEAM

TAILDOWN BEAM

SHEAR BOLTS COMPRESSION RESISTED BY THERMAL BREAK ELEVATION

TYPICAL THERMAL BREAK DETAIL IN STEELWORK

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Concrete frame Concrete frame construction is suited to larger commercial, healthcare and education buildings. Concrete frames are typically either constructed with columns and uniform depth floor slabs with no beams, or with columns and beams with thinner floor slabs spanning between the beams. Stability is provided by concrete shear walls, typically around lift and stair cores. Structural concrete is designed to Eurocode 2 BS EN 1992-1-1 and concrete mixes are defined by BS 8500–1.

Concrete grades The grade of concrete required depends on several factors such as exposure, chemical attack and whether the concrete is reinforced. The cover to the reinforcement depends on the grade of concrete, exposure and potential chemical attack (from de-icing salts and ground water). The following information is extracted from Table A.7 of BS 8500–1. (Guidance on the selection of designated and standardised prescribed concrete in housing and other applications.) For concrete subjected to sulfates and hydrostatic head of ground water, refer to a Chartered Structural Engineer. Application (concrete containing embedded metal should be treated as reinforced)

Designated concrete

Standardised prescribed concrete

Foundations Blinding and mass concrete fill Strip footings Mass concrete footings Trench fill foundations Fully buried reinforced foundations

GEN1 GEN1 GEN1 GEN1 RC30

ST2 ST2 ST2 ST2 N/A

General applications Kerb bedding and backing Drainage works to give immediate support Other drainage works Oversite below suspended slabs

GEN0 GEN1 GEN1 GEN1

ST1 ST2 ST2 ST2

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Application (concrete containing embedded metal should be treated as reinforced) Floors House floors with no embedment metal - Permanent finish to be added, e.g. screed of floating floor - No permanent finish to be added, e.g. carpeted Garage floors with no embedded metal Wearing surface: light foot and trolley traffic Wearing surface: general industrial Wearing surface: heavy industrial Paving House drives and domestic parking Heavy-duty external paving with rubber tyre vehicles

Designated concrete

Standardised prescribed concrete

GEN1

ST2

GEN2

ST3

GEN3 RC30 RC40 RC50

ST4 ST4 N/A N/A

PAV1 PAV2

N/A N/A

Precast concrete floors Precast concrete floors are used for ground floors over sloping or made-up ground where in-situ slabs may not be economic, and for upper floors where fire resisting and sound insulating construction is needed, between flats, for example. They can be used in a fully precast, ‘dry’ construction with a floating floor finish, or in a composite way with an in-situ structural topping or screed that can improve structural performance and acoustic insulation. Crane handling of the beams is normally required so they are less used on smaller projects. There are two main types of precast concrete floor, hollowcore and beam and block.

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Hollowcore floors are precast slabs 1200 mm wide with hollow cores (150 thick slab minimum). The depth of unit can vary from 100 mm to 450 mm, depending on span and loading. Beam and block floors are inverted T sections, 150–225 deep, with concrete blocks spanning between units. The blocks can span short or long direction (or alternate), depending on span and loading. Multiple beams are sometimes required under partitions. Bearing required is generally 75 mm onto steelwork and 100 mm onto masonry. Where shared bearing is required on a masonry wall, the wall should be 215 mm thick (except for a short span beam and block floors where staggered bearing might be possible). There are many manufacturers of precast concrete floors who provide a design and supply service. The following information is a small example of what is available on the internet. It is advisable to check the websites periodically as the products are revised: The load /span tables show the maximum clear span for both domestic and other loading conditions, such as nursing homes, hotels and commercial developments. These tables are provided as a guide only. Please refer to manufacturers for further information

Structures 185

Bison Flooring (part of Forterra) hollowcore (www.forterra.co.uk)

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Milbank Floors beam and block (www.milbank.co.uk)

4 Services Architects typically design services for small buildings, involving plumbers and electricians for detailed expertise on-site; as service installations have become more sophisticated, so have the regulations controlling their installation in buildings. The number of specialist designers, suppliers and installers has increased to cover demands for detection and alarm systems for fire, security, air quality, etc.; audio and video systems; home technology integration, providing benefits to other services such as heating, lighting and security; ambient energy systems, rainharvesting and grey water recycling systems; ventilation and air conditioning; more sophisticated lighting and control systems for all services either on-site or remotely. Particularly in new technologies, architects need to be wary of unofficially delegating design to subcontractors without formal design responsibility; therefore, care should be taken to ensure the correct contract is used for example JCT Minor Works with Contractors Design. For larger buildings, whose service design typically involves mechanical and electrical consulting engineers, there has been a design reaction to this elaboration in increasing use of building management systems which though improving integration have had drawbacks in loss of personal control and user understanding. While the need to improve energy efficiency has driven increasing complexity and sophistication in some areas, an alternative approach exemplified in passive design has been to aim for buildings less reliant on services, and for the remaining service systems to be more intelligible and controllable by users.

DOI: 10.4324/9781003357995- 4

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Nonetheless, for both environmental and economic reasons, demand for on-site energy generation has markedly increased. Despite the cessation of government subsidy for PV installations, reduced installation costs and a positive rate of financial return continues to drive demand for PVs on unshaded southerly oriented roofscapes and sites; energy storage via battery installations provides positive flexibility and improved returns in conjunction with increasing electric car use, though hot water storage from PVs or solar thermal remains a viable – though less flexible – alternative at much lower costs and longer life. Space and water heating using fossil-fuelled boilers has declined, though may be revived via the introduction of hydrogen to the natural gas grid. ‘Hydrogen-compatible’ gas boilers are available for replacement purposes meanwhile. In the meantime, government installation subsidy promotes heat pumps that, subject to appropriate low temperature distribution such as underfloor heating, can work to much higher coefficients of performance than boilers. Despite much higher seasonal efficiencies, water source and especially ground source heat pumps have higher installation costs so air source heat pumps lead the field.

Drainage Foul drains recommended minimum gradients Peak flow (l/s)

Pipe size (mm)

Minimum gradient

Maximum capacity (l/s)

1 >1

75 100 75 100 150

1:40 1:40 1:80 1:80* 1:150†

4.1 9.2 2.8 6.3 15.0

* Minimum of 1 WC

† Minimum of 5 WCs

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Land drains in normal soils – minimum gradients Pipe (Ø)

Gradient

Pipe (Ø)

Gradient

50 75 100 125

1:500 1:860 1:1260 1:1680

150 175 200 225

1: 2160 1:2680 1:3200 1:3720

Traps minimum sizes and seal depths Appliance

Ø trap Seal depth (mm) (mm)

Washbasin Bidet Bath* Shower* Syphonic WC

32 32 40 40 75

75 75 50 50 50

Ø trap Seal depth (mm) (mm) waste disposer urinal Sink washing machine* dishwasher*

40 40 40 40 40

75 75 75 75 75

*Where these fittings discharge directly into a gully, the seal depth may be reduced to a minimum of 38 mm. Where two or more appliances drain to a single wastepipe, the diameter should be increased, typically to 50 mm.

HepVO waterless waste valves used in lieu of traps avoid the risk of suction emptying the traps on long pipe runs. AAVs (air admittance valves) allow for greater distances between appliances and soil and vent pipes (SVPs) without compromising traps. Sources: Building Regulations–Approved Document H

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Inspection chamber covers Typical dimensions Covers are manufactured in steel and ductile iron. Covers may have single or double seals, plain or recessed tops, and be multiple leaf or continuous for ducting. Alternative features include chambered keyholes, handlift recesses and locking screws. Covers can be circular, square or rectangular in sizes from 450 mm diameter up to approx. 1200 × 675. Load classes for access covers and gully grates BS EN 124: 1994 Group

Minimum class Load

Application

1 2

A15 B125

15KN 125KN

3

C250

250KN

4

D400

400KN

5

E600

600KN

6

F900

900KN

Pedestrians only For use in car parks and pedestrian areas, only occasional vehicular access is likely For use in car parks, forecourts, industrial sites and areas with slow moving traffic also in highway locations up to 500 mm from the kerb and up to 200 mm into the verge, excluding motorways For use in car parks, forecourts, industrial sites and areas with slow moving traffic also in highway locations up to 500 mm from the kerb and up to 200 mm into the verge, excluding motorways For use in areas where high wheel loads are imposed such as loading areas, docks or aircraft pavements For use in areas where particularly high wheel loads are imposed such as aircraft pavements

Services 191

Single stack drainage system

*

 ‘Waste pipe lengths are not limited if Wavin HepVO waterless waste valves are used in lieu of traps’

Sources: Building Regulations Approved Document H Wavin

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Rainwater disposal Calculation of gutter and downpipe sizes In the UK, the maximum rainfall intensity is generally taken as 75 mm per hour or 0.0208 litres per second (l/s). Note that this does not necessarily mean only high rainfall areas such as West Wales and Scotland but, in surprisingly odd pockets like Norfolk and Oxford, heavy downpours can exceed this figure. To calculate the size of rainwater goods, it is necessary to determine the effective roof area, which, in the case of pitched roofs, is as follows: Effective roof area = (H ÷ 2 + W) × L = m2 Where H = vertical rise between eaves and ridge W = plan width of slope L  = length of roof To determine the maximum flow, multiply the effective area by 0.0208. Manufacturers’ websites also offer this service.

Typical maximum flow capacities Outlet at one end of roof Gutter mm

Downpipe mm

75 half round 51 Ø 110 half round 69 Ø 116 square 62 sq

Outlet at centre of roof

Level gutter m 0  l/s

Gutter to fall m2  l/s

Level gutter m2   l/s

15 0.33 46 0.96 53 1.10

19 0.40 61 1.27 72 1.50

 25 0.54  30 0.64  92 1.91 122 2.54 113 2.36 149 3.11t

Gutter to fall m2  l/s

Refer to manufacturers’ websites for actual flow capacities, as profiles of gutters can vary.

Services 193

Rule of thumb A 100–112 mm gutter with 68 mm Ø downpipe placed at the centre of the gutter will drain 110 m2 effective roof area; placed at the end of the gutter will drain 55 m2 effective roof area. Gutter will drain more if laid to slight (1: 60) fall.

Sustainable Urban Drainage Systems (SUDS) SUDS are a sustainable approach to surface water management and can be used to minimise the impacts from development on the quantity and quality of runoff, and to maximise amenity and biodiversity opportunities. It is a key component in the management of flood risk and its implementation is driven by primary legislation as well as non-statutory guidance. In England and Wales, surface water management is governed by the Flood and Water Management Act of 2010 that placed strategic management of flooding in the hands of the Environment Agency, and created Lead Local Flood Authorities (LLFAs, typically county councils) to deal with local issues with (in some areas) Local Drainage Boards. They have the power to set local bylaws and are statutory consultees for planning applications. Schedule 3 of the Act also created SUDS approval bodies (SAB’s), although this has only been enacted in Wales, where there is now a formal approval process. In England, the approach is also informed by non-statutory guidance with the following key drivers: 1. Section H of the Building Regulations (gives priority to disposal of surface water by infiltration). 2. Local planning authority conditions, informed by DEFRA non-statutory technical publications (on-line resource) and the statutory consultees.

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3. Statutory water authorities controls on discharge of surface water into sewers (only where infiltration is impractical) when attenuation (site storage) will be required. DEFRA design guidance requires comparison between the post-development condition and the equivalent ‘greenfield’ pre-development surface water runoff. Both peak discharge rate and volume of discharge must be controlled with allowances for climate change (as much as a 40% increase in rainfall intensity). Design guidance is given in the Environment Agency publication, ‘Preliminary Rainfall Management for Developments’ (1) which gives a methodology for estimation of greenfield runoff rates and storage requirements. Larger-scale developments will almost certainly require computer analysis. On a smaller scale, design tools are also provided on-line by HR Wallingford. The bible for SUDS design is the SUDS Manual (2), revised in 2015, and available for download from the CIRIA website. SUDS schemes work by maximising infiltration and provide interception storage and treatment by encouraging flow across soft landscaping, or through permeable paving. SUDS features provide required storage in swales basins or pond or below ground in voided aggregates or crates that should be integrated in a landscaped solution with maintenance and safety considered in design. Water authorities typically use 30-year storm return periods with a no flood requirement for design of components within sewerage systems. This is also a DEFRA requirement for sewerage systems within developments. This means excess water has to be contained within the system, which may include designed SUDS components to provide surface storage. In Wales, the SAB is tasked to ensure that drainage proposals for all new developments are fit for purpose. Any new development

Services 195

of at least 2 properties or over 100 m2 of construction will require a SABs application. This includes extensions that are over 100 m2. Pre-applications are encouraged because: • The application process is quicker. • It can save unnecessary redesign costs and time. • You can discuss issues that arise and design accordingly. Construction work cannot start until the application is approved (the SAB has 7 weeks to determine applications, 12 weeks where an Environmental Impact Assessment is required). The application is very strict and has set requirements that must be followed. Any omissions will require resubmission, no further discussion is possible. Because of the potential for delay, construction level drainage design should be considered early in the design process and this will require: °° Topographical survey of the site including any nearby water courses. °° A detailed CCTV survey of existing site layout, drainage system and catchment areas (if appropriate) with cover and invert levels, falls, condition, pipe diameter. °° Ground investigation report that includes geology, hydrology, groundwater and contamination testing. °° Infiltration tests to BRE365. °° Surveys of any existing drainage systems or water bodies to which SUDS may discharge. °° Flood risk assessment demonstrating flooded areas for a 1 in a 100 year storm. In Scotland, the primary legislation is the Water Environment (Controlled Activities) (Scotland) Regulations 2011, and this requires significant development with discharge to water to pass through SUDS systems (not single dwellings, or discharge to coastal waters). General design guidance is provided by the SUDS working party (3) which references the SUDS Manual (2).

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In Northern Ireland, SUDS implementation is via the planning system, with Planning Policy Statement 15 the relevant document. Sources 1. Preliminary Rainfall Management for Developments, R&D Technical Report W5–074, EA/DEFRA, 2005 HR Wallingford 2. The SUDS Manual, CIRIA C753 2015 3. The Water Assessment and Drainage Assessment Guide (WADAG), SUDSWP, January 2016

Water supply regulations The Water Supply (Water Fittings) Regulations 1999 (and subsequent amendments) supersede the Water Supply Byelaws. Their aim is to prevent: waste, misuse, undue consumption, contamination or false measurement of water supplied by a Water Undertaker (WU). The regulations should be read in conjunction with the WRAS Guide, which includes detailed information of sizes, flow rates, valves, etc. Below is a VERY BROAD and BRIEF interpretation of the regulations.

Application of the regulations The regulations apply only to fittings supplied with water by a WU. They do not apply to water fittings for non-domestic or non-food production purposes providing the water is metred; the supply is for less than one month (three months with written consent) and no water can return through a metre to a mains pipe. They do not apply to fittings installed before 1 July 1999.

Notification Water undertakers must be notified of the following:

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Erecting any building, except a pond or swimming pool, of less than 10,000 litres capacity Altering any water system in non-residential premises Changing the use of a property Building over or within 2 m of a public sewer. A CCTV survey may be necessary Installing: • • • • • • • • • •

A bath with a capacity greater than 230 litres A bidet with ascending spray or flexible hose A single shower unit with multi-head arrangement A pump or booster drawing more than 12 litres/minute A water softener with a waste or needing water for regeneration or cleaning A reduced pressure zone valve or any mechanical device that presents serious health risks A garden watering system other than a hand-held hose External pipes higher than 730 mm or lower than 1350 mm in relation to ground level An automatically filled pond or swimming pool with a capacity of more than 10,000 litres A unit that incorporates reverse osmosis

Contractor’s certificate Contractors approved by the WU must issue certificates to clients stating that the work complies with the regulations. For items of Notification (see above) copies of these certificates must be sent to the WU. Contravention of the regulations may incur a fine not exceeding £1000 (in 2000 AD).

Fluid categories Water is described in five fluid categories ranging from ‘wholesome’ water supplied by a WU to water representing serious

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health hazards. These categories are used, amongst other things, to define which type of backflow prevention (see below) is required.

Contamination and corrosion Water for domestic use or food purposes must not be contaminated by materials such as lead and bitumen. Water fittings must not be installed in contaminated environments such as sewers and cesspits.

Quality and testing Water fittings should comply with British Standards or European equivalent and must withstand an operating pressure of not less than 1.5 times the maximum operating pressure. All water systems must be tested, flushed and, if necessary, disinfected before use.

Location Water fittings must not be installed in cavity walls, embedded in walls or solid floors, or below suspended or solid ground floors unless encased in an accessible duct. External pipes underground must not be joined by adhesives nor laid less than 750 mm deep or more than 1350 mm deep unless written consent is obtained.

Protection against freezing All water fittings outside buildings or located within buildings but outside the thermal envelope should be insulated against freezing. In very cold conditions, in unheated premises, water should be drained down before the onset of freezing or alternative devices installed to activate heating systems.

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Backflow protection Except where expanded water from hot water systems is permitted to flow backwards, water installations must have adequate devices for preventing backflow as follows: • To prevent backflow between separate premises • Connection of grey or rainwater to a ‘wholesome’ water pipe • Bidets with flexible hoses, spray handsets, under-rim water inlets or ascending sprays • WC cisterns with pressure flushing valves • WCs adapted as bidets • Baths with submerged inlets (e.g. jacuzzis) • Non-domestic washing machines and dishwashers • Sprinkler systems, fire hose reels and fire hydrants • Garden hoses and watering systems

Cold water services Every dwelling, including those in multi-storey dwellings should have separate stop valves for mains entry pipes inside each premises. Drain taps must be provided to completely drain water from all pipes within a building. All domestic premises must have at least one tap for drinking water supplied directly from the mains.

Cold water cisterns Cold water cisterns for dwellings are no longer mandatory, provided there is adequate water flow rate and mains pressure in the street. Check this with the WU before designing new installation.

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Cisterns must be fitted with float valves and servicing valves. Overflow/warning pipes with vermin and insect-proof screens must be fitted to discharge conspicuously outside. Where cisterns are joined together, care must be taken to avoid one cistern overflowing into another and that water is fully circulated between cisterns and not short-circuited. Cisterns should be insulated and be fitted with light and insect-proof lids. About 350 mm minimum unobstructed space must be provided above the cistern for inspection and maintenance.

Hot water services A temperature relief valve or combined temperature and pressure relief valve shall be provided on every unvented hot water storage vessel with a capacity greater than 15 litres. Expansion valves must be fitted to unvented hot water systems larger than 15 litres. Primary circuit vent pipes should not discharge over domestic cisterns nor to a secondary system. Secondary circuit vent pipes should not discharge over feed and expansion cisterns connected to a primary circuit. Ideally, hot water should be stored at 60ºC and discharged at 50ºC (43ºC for shower mixers). Long lengths of hot water pipes should be insulated to conserve energy.

Garden water supplies Double check valves (DCVs) must be fitted to hose union taps in new houses. Hose union taps in existing houses should be replaced with hose union taps that incorporate DCVs. Watering systems must be fitted with DCVs as well as pipe interrupters with atmosphere vent and moving element at the hose connecting point or a minimum of 300 mm above the highest point of delivering outlet.

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Pools and fountains filled with water supplied by a WU must have an impervious lining.

WCs and urinals Single flush cisterns to WCs should not exceed 6 litres capacity. Manual pressure flushing valves to WC cisterns must receive at least 1.2 litres/second flow at the appliance. WC cisterns installed before July 1999 must be replaced with the same size cistern. Existing single flush cisterns may not be replaced by dual-flush cisterns. Automatic urinal flushing cisterns should not exceed 10 litres capacity for a single urinal and 7.5 litres/hour per bowl, stall or 700 mm width of slab. Urinal pressure valves should deliver no more than 1.5 litres per flush. Low water consumption WC pans and cisterns are available down to 4 litres. Passive infra-red (PIR) flush controls are available to minimise wastage in urinals. Waterless urinals are available but require a careful cleaning regime. Sources: Water Supply (Water Fittings) Regulations 1999 with amendments in 2005 and 2013. The WRAS Water Regulations Guide

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Water storage and use Plastic cold water cisterns Rectangular Litres

Gallons

Size l × w × h mm

18 68 91 114 182 227

 4 15 20 25 40 50

442 × 296 × 305 600 × 425 × 425 665 × 490 × 510 736 × 584 × 533 940 × 610 × 590 1155 × 635 × 600

Litres

Gallons

Size Ø @ top × h mm

114 227 455

 25  50 100

442 × 533 838 × 610 1041 × 787

Circular

Source: Kingspan Environmental Ltd. Note: One litre of water weighs one kilogram so full weight of cistern equals litre capacity in kilograms plus empty weight.

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Water hardness

Hard water supplies lead to lime-scale formation in and around appliances; this leads to substantial reductions in efficiency, particularly in boilers and hot water cylinders. Scale formation can be reduced by fitting scale reducers to incoming cold mains. These work by magnetism, electronic charge or chemical treatment to reduce the amount of hard scale formed and clear scale deposits, retaining the calcium carbonate in suspension; they are low in cost and appear to have no health effects. Water softeners remove the calcium carbonate from the water, rendering it ‘soft’; they should be fitted near drinking water taps – typically at kitchen sinks. They require recharging with salt at regular intervals and are substantially more expensive to install and maintain than conditioners. In hard water areas, it is advisable to fit conditioners or softeners to all buildings with hot water systems.

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Hot water usage Typical average consumption – litres Bath Shower Power shower Handwashing Hairdressing Cleaning Kitchen sink

60 per bath 2.5 per minute 10–40 per minute 2 per person 10 per shampoo 10 per dwelling per day 5 per meal

Cold water fill appliances Dishwasher Washing machine

13 per cycle 45–70 per cycle

Hot water storage Typical storage requirements @ 65ºC – litres per person House or flat Office Factory Day school Boarding school Hospital Sports centre Luxury hotel

30  5  5  5 25 30 35 45

Measures to reduce water consumption With regard to the reduction in water consumption, the general consensus is that as a population, we should all make a commitment to save as much as we can. The following lists some of the measures that can be introduced to reduce water consumption. Installation of water metres. Installation of flow restriction valves on taps.

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Installation of low flow shower heads. Installation of dual flow WC cisterns. Installation of auto flush urinal controls. Installation of grey and/or rainwater harvesting. Installation of leak detection and isolation systems.

Mains pressure cylinders For buildings with good mains pressure and appropriately sized water main pipework, mains pressure hot water supply offers significant advantages including equal pressure hot and cold supplies, adequate pressure at all locations for showers, location of the cylinder anywhere and elimination of cold water storage tanks; existing systems of pipework need to be checked for mains pressure. Appropriate mains pressure cylinders are widely available in stainless steel and enamelled mild steel, pre-insulated, with single or double coils for boiler and solar applications, though in fewer sizes than copper tank-fed cylinders.

Unvented stainless steel indirect hot water cylinders Capacity L

Height mm

Diameter mm

ErP rating litres

Standing heat loss W

120 150 180 210 250 300

1001 1187 1371 1561 1806 2076

580 580 580 580 580 580

A A B B B C

37 40 50 62 66 77

Source: Tribune Xe Indirect Cylinders by Kingspan Environmental. 45 mm insulation is included within the diameter of the cylinder. Building Regulations require hot water cylinders to have factory applied insulation ­designed to restrict heat losses to 1 watt per litre or less.

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Cylinders for solar water heating Hot water cylinders installed with solar water systems should be as large as practicable so as to maximise the efficiency of the system by storing solar heated water; although the solar coil in the base of the cylinder will heat the whole cylinder, the boiler coil in the upper part will heat only the upper part, so, when there is no further pre-heating from the solar system, at night, for example, once the solar hot water is used, the boiler can heat only half the cylinder capacity.

Thermal stores Whereas conventional hot water cylinders store the hot water that is used, thermal stores store the primary water as a heat storage ‘battery’ that provides for hot water usually via an internal pipe coil near the top of the store; heating outputs are typically around the middle or upper third of the store and inputs often from several heat sources, such as boilers, woodstoves, etc., are towards the base, with the solar thermal input usually the lowest. Typically, thermal stores are larger than hot water cylinders, often of several hundred litre capacity for a house; with substantial insulation, they are bulky as well as heavy, so provision needs to be made early on in design. They are especially efficient for intermittent inputs, so work well with solar, wind and biomass energy.

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U-values To understand the use of U-values, it is necessary to distinguish between the thermal measurement expressions below: • Thermal conductivity (K-value): The heat (W) transmitted through unit area (m2) of a material of unit thickness (m) for unit temperature difference (K) between inside and outside environments, expressed as W/mK (or W/m ºC). • Thermal resistivity (R-value): The reciprocal of thermal conductivity, that is, mK/W (or m ºC/W). It measures how well a material resists the flow of heat by conduction. • Thermal resistance (R-value): This means how well a particular thickness of material resists the passage of heat by conduction, calculated from the R-value in units of m2K/W (or m2 ºC/W). • Thermal transmittance (U-value): The reciprocal of thermal resistance, that is, W/m2K (or W/m2 ºC). This measures the amount of heat transmitted per unit area of a particular thickness per unit temperature difference between inside and outside environments.

U-value calculation formula U=

RSI + RSO

1 + R A + R1 + R 2 + R3 

where RSI RSO R A

= thermal resistance of internal surface = thermal resistance of external surface = thermal resistance of air spaces within construction R1, R2, R3, etc. = thermal resistance of successive components R=

1 thickness of material mm × K-value 1000

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Summary of U-values: Standard U-values for new construction elements ­England only (figures account for repeating thermal bridges) Limiting U-values for new fabric elements and air permeability in new and existing dwellings Element type

L1A maximum U-value (W/ m2K)

L1B maximum U-value (W/ m2K)

All roof types Wall Floor Party wall Swimming pool basin Window Rooflight Doors

0.16 0.26 0.18 0.20 0.25 1.6 2.2 1.6

Air permeability

8.0m3/(h.m2)@50 Pa 1.57m3/(h.m2)@4 Pa

0.15 0.18 0.18 n/a 0.25 1.4 or WER band B minimum 2.2 1.4 or WER band B minimum 1.4 or WER band C minimum (if over 60% glazed) n/a

Source: ADL 2021 Volume 1 Dwellings Tables 4.1 and 4.2.

Limiting U-values for new fabric elements and air permeability in new and existing buildings Element type

L2A maximum U- value (W/m2K)

L2B maximum U-value (W/ m2K)

Flat roof Pitched roof Wall Floor Swimming pool basin Window in buildings similar to dwellings All other windows, roof windows and curtain walling Rooflight Pedestrian doors including glazed doors Vehicle access and other large doors

0.18 0.16 0.26 0.18 0.25 1.6 or WER band B minimum 1.6

0.18 0.16 0.26 0.18 0.25 1.6 or WER band B minimum 1.6

2.2 1.6

2.2 1.6

1.3

1.3

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Element type

L2A maximum U- value (W/m2K)

L2B maximum U-value (W/ m2K)

High use entrance doors Roof ventilators Air permeability

3.0 3.0 8.0m3/(h.m2)@50 Pa

3.0 3.0 n/a

Source: ADL 2021 Volume 2 Buildings Table 4.1.

Standard U-values for new construction elements Wales only (figures account for repeating thermal bridges). At the time of writing, July 2022, the Regulations for Wales have not been updated as they have been done in England. It is expected the values below will be similar to those for England. Exposed element

Pitched roof (between 11º and 70º) with insulation between rafters Pitched roof with insulation between joists Flat roof (0º–10º) or roof with integral insulation Cavity and solid walls Party walls Floors, including ground floors and basement floors Swimming pool basin Window, roof window, rooflight All doors (except high usage entrance doors*) Vehicle access and similar large doors

W/ m2K L1A

L1B

L2A

L2B

0.15

0.15

0.25

0.18

0.15

0.15

0.25

0.15

0.15

0.15

0.25

0.18

0.21 0.20 0.18

0.21 N/A 0.18

0.35 N/A 0.25

0.26 N/A 0.22

0.25 1.6 1.6

0.25 1.6 1.6

0.25 2.2 2.2/*3.5

0.25 1.8 1.8/*3.5

N/A

N/A

1.5

1.5

Note the differences between LA and LB, the new lower U-values in existing buildings are there to make up for some shortfall in the existing, unaltered building.

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Upgrading retained thermal elements (If the retained element is worse than the threshold, it should be improved to the minimum value or better) Limiting U-values for existing elements in existing dwellings Element type

L1B threshold maximum U-value (W/ m2K)

L1B maximum U-value (W/ m2K)

Roof Wall – cavity Insulation Wall – internal or external insulation Floor

0.35 0.70 0.70

0.16 0.55 0.30

0.70

0.25

Source: ADL 2021 Volume 1 Dwellings Table 4.3.

Limiting U-values for existing elements in existing buildings Element type

L2A threshold maximum U-value (W/ m2K)

L2B maximum U-value (W/ m2K)

Flat roof Pitched roof insulation at ceiling level Pitched roof insulation at rafter level Wall – cavity insulation Wall – external or internal insulation Floor

0.35 0.35 0.35 0.70 0.70 0.70

0.18 0.16 0.18 0.55 0.30 0.25

Source: ADL 2021 Volume 2 Buildings Table 4.12.

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R-values Surface resistance R-values m2K/W normal exposure Rsi inside Rso outside surface surface

Roof/ceiling Wall floor

0.10 0.12 0.14

0.04 0.06 0.04

Air space R-values 25 mm exposure

m2K/W RA

In cavity wall Loft space under sarking Between metal cladding and lining In cold flat roof Loft space under metal cladding Between roofing tiles and felt Behind tile hanging

0.18 0.18 0.16 0.16 0.14 0.12 0.12

K-values Thermal conductivity of typical building materials Material

kg/m3 W/mK

Material

kg/m3 W/mK

Asphalt blocks 19 mm Light weight Medium weight Heavy weight Bricks Exposed Protected Calcium silicate Board Cellulose Loose fill

1700 1200 1400 2300 1700 1700 875 32

Mortar Phenolic foam Plaster

1750 30 1280 1570 640 950 600 80 25

Chipboard concrete

Quilt

800 500 1200 2100 120 960 300 25

Flax

Slabs

40

Foamglass Glass Hardboard Hemp Hempcrete

Slabs Sheet Standard Slabs 200 mm spray render Slabs

Cork Felt/bitumen Fibreboard Fibreglass

Isocyanurate foam Mineral wool

100 2500 900 40 225

0.50 0.38 0.51 1.63 0.84 0.62 0.17 0.038 –0.040 0.15 0.16 0.38 1.40 0.045 0.50 0.06 0.033 –0.04 0.038 –0.040 0.038 1.05 0.13 0.40 0.25

30

0.022

Quilt

12

Slab

25

0.033 –0.04 0.035

Aerated slab Lightweight Dense Board 3 layers

Normal Board Gypsum Sand/cement Vermiculite Plasterboard Gypsum Plywood(softwood) Board Phenolic foam board Polystyrene Expanded Polyurethane

Board

OSB Rendering Roofing tiles

Board External Clay Concrete

Screed Sheeps wool Stone

Stone chippings Strawbale Timber Vermiculite Woodwool

30

680 1300 1900 2100 1200 Slabs 19 Reconstructed 1750 Sandstone 2000 Limestone 2180 Granite 2600 1800 110 Softwood 650 Loose 100 Slabs 600

0.80 0.020 0.46 0.53 0.19 0.16 0.12 0.02 0.032 –0.040 0.025 –0.028 0.13 0.50 0.85 1.10 0.41 0.040 1.30 1.30 1.50 2.30 0.96 0.055 0.14 0.063 0.11

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Conservation of fuel and power The requirement of Building Regulations Part L 2021 is that reasonable provision shall be made for the conservation of heat and power by limiting heat gains and losses through the building fabric and services, by providing energy-efficient services and controls, and by providing the building’s owner with sufficient information for efficient operation and maintenance. The regulations are split into L1A for new dwellings, L1B for existing dwellings, L2A for new non-dwellings and L2B for existing non-dwellings. There are two documents for Part L. Approved Document Volume 1: Dwellings, and Approved Document Volume 2: Buildings other than Dwellings. These documents each cover the requirements for both new and existing buildings and supersede any previous documents, including the Compliance Guides for Services that are now included within each of the 2021 Approved Documents above.

Dwellings For New Dwellings, there are 3 metrics that must be achieved by the Proposed dwelling design over a Notional dwelling design. These are undertaken within the SAP calculation. a. The Target Primary Energy Rate – in kWh PE/m2 /yr. – this is influenced by the dwelling fabric and fuel. The Design Dwelling Primary Energy Rate must be equal to or lower than the Target Primary Energy Rate. b. The Target Emission Rate – in kgCO2/m2 /yr. – this is influenced by the dwelling fabric and fuel. The Design Dwelling Emission Rate must be equal to or lower than the Target Emission Rate.

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c. The Target Fabric Energy Efficiency Rate – in kWh/m2 /yr. – this is influenced by the dwelling fabric only. The Design Dwelling Fabric Energy Efficiency Rate must be equal to or lower than the Target Fabric Energy Efficiency Rate. The dwelling must also achieve minimum standards of thermal efficiency in both the construction element U-values and air tightness, the risk of overheating in summer must be avoided by careful design of ventilation, glazing orientation and shading, and the construction should be designed to meet minimum standards to avoid significant thermal bridging. Note, SAP no longer provides a basic overheating assessment; this must now be undertaken separately from guidance in Approved Document Part O. A strategic approach should be adopted whereby the aim is to reduce energy demands overall, meet the remaining energy demand with high efficiency systems that are well controlled, and then consider the use of renewable energy to offset the energy demand; a renewable energy system should not be used as a basis for a poorly insulated building. Works to existing dwellings, for example, Extensions, will need to comply as for a new build, and the area of windows, doors and roof lights should not exceed 25% of the total floor area. For a material Change of Use, and Renovation, that is, a conversion, a ‘reasonable upgrade’ is required that is technically, functionally and economically feasible and can be demonstrated by improving the existing construction elements to minimum standards whose simple payback is no more than 15 years and in addition improving the building services.

Non-dwellings For New Non-Dwellings, there are 2 metrics that must be achieved by the Proposed building design over a Notional

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building design. These are undertaken within the SBEM calculation. a. The Target Primary Energy Rate – in kWh PE/m2 /yr. – this is influenced by the building fabric and fuel. The Design Building Primary Energy Rate must be equal to or lower than the Target Primary Energy Rate. b. The Target Emission Rate – in kgCO2/m2 /yr. – this is influenced by the dwelling fabric and fuel. The Design Building Emission Rate must be equal to or lower than the Target Emission Rate. For the Building Services in Non-Dwellings, it is important that the guidance in Sections 5 and 6 of the Approved Document Volume 2: Buildings other than dwellings is referred to for minimum performance criteria. For both L1B and L2B, there is guidance as to how to apply the regulations to historic buildings, those of special architectural interest, and those that are Listed or in Conservation Areas. When trying to achieve compliance for Part L1A, New Dwellings, perhaps the most useful information is the Notional Specifications for new Dwellings. The Notional specification, if followed, would usually achieve a pass for Part L. A quick glance through will soon highlight that the values used in the Notional calculations, to which the Proposed design is compared, are somewhat better than those minimum values and efficiencies used throughout the Approved Document and highlighted in this book. As the calculation is totally flexible, in that if one element is worse than the Notional, by improving on another, compliance can be achieved. The Notional Specification for Dwellings is in Approved Document Volume 1: Dwellings Table 1.1. Unfortunately, there is no longer a Notional Specification for Non-Dwellings, this is because the types of buildings and

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different permutations for building services are too numerous. Similarly, there are no Notional Specifications for Part L1B and L2B Existing buildings for the same reason.

Heat losses As a rough guide, building heat losses will be between 20 and 50 W/m3. For normal conditions and temperatures, 30 W/m3 is average. Higher figures for tall, single-storey buildings or large areas of glazing, lower figures for well-insulated buildings with minimal exposure, for example, a building with 400 m3 of heated space may require between 8 and 20 kW depending on conditions. Recommended indoor temperatures

ºC

Warehousing; factory – heavy work General stores Factory – light work; circulation space Bedroom; classroom; shop; church Assembly hall; hospital ward Offices; factory – sedentary work Dining room; canteen; museum; art gallery Laboratory; library; law court Living room; bed-sitting room; Sports changing room; operating theatre Bathroom; swimming pool changing room Hotel bedroom Indoor swimming pool

13 15 16 18 18 19 20 20 21 21 22 22 26

Source: Series A Design data CIBSE.

Non-repeating thermal bridging and air permeability Air permeability Air permeability for new buildings has a maximum level of 8 m3/(h.m2) measured at 50 pascals. This is determined by the

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air pressure test conducted on completion of the construction. Every Building must have its own air test. Passivhaus buildings need to meet a maximum level of 0.6 m3 (h.m2) at 50 pascals and the equivalent Enerphit standard for refurbishment is 1 m3 so even recently improved UK Building Regulations have a long way to go to reach zero carbon for new buildings. In detailed design for improved air tightness, it is important that condensation risk is taken into account and that effective ventilation and/or drainage are provided to clear it.

Non-repeating thermal bridges Non-repeating thermal bridges occur at junctions between insulated elements in the building, for example, walls and floors, at lintels, sills and jambs and are represented as a linear psi value in W/m. In the SAP calculation for dwellings, all linear psi values are added together and divided by the total building  fabric area to give a total linear transmittance ‘y’ value in W/m2. A proven method of designing for minimum non-repeating thermal bridges must be adopted. This is undertaken by either selecting psi values calculated by an accredited person or from an approved source, for example, LABC, or from manufacturer’s own details, for example, Kingspan. The appropriate psi value is then entered into the calculation. Photographic evidence of example junctions is required, taken during the construction phase, before an as-built assessment can be completed. Table R1 & R2 in SAP version 10.2 Document details all the junctions that are measured within SAP. Non-repeating thermal bridges can have a significant effect on the heat losses of the building, particularly as the construction U-values become lower, the % of total building heat loss via thermal bridges will increase. Careful detailing and on-site

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checking of the construction are important to ensure these are kept to a minimum. In Non-Dwellings, the same criteria apply in terms of psi value sources; however, there are far fewer junctions to be input into an SBEM calculation and subsequently their impact on the overall result is less than it is in SAP for dwellings. The psi values are only input for new buildings; they are not required for work on existing buildings; however, it obviously makes sense to apply the same attention to detail wherever possible to reduce unwanted heat losses.

Heat loss calculation The heat loss from a building is the addition of all the individual fabric heat losses of the doors, windows, walls, floor and ceilings, plus any ventilation loss. Fabric heat losses arise when heat is transferred from the warm interior to the cold exterior through the external surfaces of the building. This occurs by a combination of conduction, convection and radiation.

Fabric heat loss calculation, expressed as Total Watts Total W = Sum of (Element area m2 × U-value of fabric ) × (inside ºC – outside ºC) Each element must be calculated separately and then added together. For inside temperatures, see list of Recommended Indoor Temperatures on p. 153. For outside temperature – 1ºC is the ­figure normally used in the UK.

218 Architect’s Pocket Book

Ventilation loss occurs when the warm air inside the building leaves and is replaced by cool air from outside, this is the heat lost through cracks, service openings and gaps in doors and windows, for example. With closed windows and an average level of draught­-proofing, the following air changes per hour are assumed: Living rooms, bed-sitting rooms Bedrooms Kitchens and bathrooms Halls and stairways Rooms with chimneys add

= = = = =

1 0.5 2 1.5 11

Ventilation heat loss calculation, expressed as Total Watts Total W = 1/3 × number of air changes per hour × volume m3 × (inside ºC – outside ºC) Source: The Green Building Bible Vol.2, Fourth Edition.

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Central heating and hot water systems

Source: Ideal Standard Ltd (revised for solar)

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Heating and hot water systems When specifying heating and hot water systems, reference should be made to either Approved Document Volume 1: Dwellings or Approved Document Volume 2: Buildings other than Dwellings, for the minimum efficiencies the equipment must achieve: although these minimum efficiencies will need to be improved upon to achieve compliance. The Approved Documents provide information for both new and replacement systems. The Approved Documents also provide details of the minimum controls packages that are appropriate for each heating type, and will vary depending on the type of equipment to be installed. Heating and hot water generation are typically selected from: Mains natural gas/likely hydrogen mix LPG Oil Direct electric Ground source, water source or air source heat pumps Solar thermal or photovoltaic Wind, hydro where site conditions permit For improved performance and reduced reliance on fossil fuels, heat pumps are an increasingly viable alternative to boilers though they rely for good coefficients of performance on low temperature heat outputs, ideally via underfloor heating or if necessary via doubled up radiator sizes. Ground source and water source heat pumps provide best winter performance, especially compared with air source heat pumps but air source heat pumps have much lower installation costs. On 26 September 2015, the way boilers are rated for energy efficiency changed; SEDBUK was replaced by the Energy-­ related Products (ErP) directive, bringing a new rating system into effect. The ErP was launched as part of the EU’s plans to phase out inefficient appliances.

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Below is a link to a boiler manufacturer site detailing the ErP. https://www.viessmann.co.uk/heating-advice/boiler-­ratingsexplained#:~:text=The%20SEDBUK%20rating%20system%20 was, Directive%20rating%20system%20in%202015.

Radiators Radiators – despite their name – work largely by convection, and ideally need to be located to suit the airflows created, traditionally under windows to counteract cold downdraughts, though this is less critical with double glazing and draught stripping. Standard radiators are made as pressed steel panels; some higher performance radiators are made in aluminium; thermostatic control – usually by TRVs – for each radiator is advisable for energy efficiency; equivalent control of underfloor circuits is provided via individual room thermostats. Typical panel radiators – steel Heights: 300, 450, 600, 700 mm Lengths: 400–3000 in 100 mm increments Type Single panel without convector Single panel with convector Double panel with convector Double panel with double convector

Thickness 47 mm 47 mm 77 mm 100 mm

Approx output* 1500 W/m2 2200 W/m2 3300 W/m2 4100 W/m2

* m2 measured on elevation.

Typical column radiators – steel Heights: 185, 260, 300, 350, 400, 450, 500, 550, 600, 750, 900, 1000, 1100, 1200, 1500, 1800, 2000, 2200, 2500, 2800, 3000 mm

222 Architect’s Pocket Book Type Two columns wide Three columns wide Four columns wide Five columns wide Six columns wide

Thickness

Approx output*

62 mm 100 mm 136 mm 173 mm 210 mm

2150 W/m2 3000 W/m2 3700 W/m2 4600 W/m2 5400 W/m2

Sources: Stelrad.

* m2 measured on elevation.

For efficient use of heat pumps with low output temperatures, radiators typically have to be around twice the size of those used with boilers.

Underfloor heating This is the most widely used large-scale radiant heating system that has the efficiency benefit of promoting a temperature gradient to match human comfort, that is, ‘warm feet and cool head,’ and avoids the build-up of hot air at ceiling level, particularly in high spaces. With comfort achievable at lower temperatures, fuel savings of 20% or more as compared with a radiator system, are common. Floors are typically heated by oxygen-barriered polythene hot water pipes embedded in insulated screed or slab, or set into insulation below timber floors. With pipes at 150 mm centres, heat outputs of around 120 W per sqm for a tiled or similar floor finish can be expected from a water temperature of 45°C. The low water temperature allows for the most efficient use of condensing boilers, and especially for lower output temperature heat sources such as heat pumps or solar thermal stores. Underfloor heating also has particular advantages in terms of building fabric benefits for traditional and historic buildings; it can be installed where appropriate as part of a fully permeable floor using foamed glass bead insulation and limecrete so as to avoid concentrating dampness in traditional walling, as well

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as providing widest heat distribution and lower temperature impacts on historic materials. Electric underfloor heating has similar design advantages but typically high running costs and the environmental disadvantages of high primary energy use as with any electrical heating. PV installations with battery storage can offer an alternative low primary energy use version of electric space heating.

Solar water and space heating Solar thermal water and space heating can be provided via evacuated tube or flat plate absorbers connected to twin coil hot water cylinders or thermal stores via differential controllers; large capacity and high value insulation is essential for cylinders and stores to achieve best value. For a typical domestic installation of 4 to 6 sqm of flat plate collectors (or 2 to 3 sqm of evacuated tubes), a cylinder size of 250 to 400 L might be appropriate but system sizing should take account of use, panel location, pitch etc. Connecting pipework should be kept to a minimum and be well insulated. Panels may be free-standing, roof-mounted or roof-integrated. Most systems use anti-freeze though ‘drain-back’ systems are also available. Systems can be retro-fitted to existing hot water installations though not with most types of combi boilers. Although solar thermal will often provide sufficient hot water for a household through the summer, back-up heating is required in addition; in winter, solar thermal will provide pre-heating at best; steeper pitch collectors work more effectively for low-­ angle winter sun. Solar thermal contributions to space heating are modest in the UK climate but can contribute to base-load via thermal stores, or at substantial capital cost via seasonal heat stores. Solar thermal systems are less affected by partial shade than solar PV systems and in the case of evacuated tube collectors, provide more than double the energy output of the same area of PVs, so can be more viable for restricted areas.

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Surplus PV generation can contribute towards water and space heating by an immersion heater fitted to a thermal store; Immersun and other proprietary devices are available to control this. Government subsidy via the Renewable Heat Incentive offering an incentive for solar thermal installations and heat pump installations was replaced by the Boiler Upgrade Scheme from 1–4–22 to 1–4–25 that provides one-off grants. A more favourable VAT rate – 0% instead of 5% applied to energy-­ saving measures from the same date.

Ventilation The Building Regulations–Approved Document F, has been ­updated in June 2022 and it is important to read the document.

Volume 1: Dwellings, contains the following sections plus appendices Section 1: Ventilation provision Section 2: Minimising the ingress of external pollutants Section 3: Work on existing dwellings Section 4: Commissioning and providing information

Volume 2: Buildings other than dwellings, contains the following sections plus appendices Section 1: Ventilation provision Section 2: Minimising the ingress of external pollutants Section 3: Work on existing dwellings Section 4: Commissioning and providing information Ventilation tables for different building types can be found in AD F Volumes 1 and 2

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Note: AD F has key interactions with Approved Documents B, J, L, K, M, O

Means of ventilation Required by the Building Regulations for rooms with intermittent extract systems

Dwellings with multiple floors Purge ventilation

Minimum equivalent

Minimum intermittent

(e.g. opening window)

area of background ventilation

extract rates or PSV*

See Table 1.4 1/20th floor area 1/10th floor area Subject to opening angle Kitchen Opening window or door capable of giving air changes/elsewhere or PSV hour/room or fan with 15 mins overrun timer Utility room Opening window (unsized) or fan with 15 mins overrun timer Bathroom (with Opening window or without WC) (unsized) or fan with 15 mins overrun timer Sanitary 1/20th floor area or accommodation fan @ 6 l/s (21.6 m3/h) (separate from bathroom) Habitable room

See Table 1.7 See Table 1.1 No requirement 8000 mm2

8000 mm2

30 l/s (108 m3/h) adjacent to hob or 60 l/s (216 m3/h)

No minimum

30 l/s (108 m3/h) or PSV

4000 mm2

15 l/s (54 m3/h) or PSV

No minimum

No requirement (but see rapid ventilation)

Buildings other than dwellings See AD F Volume 2 Section 1 and table 1.1 for different building types and accommodation

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Means of ventilation Definitions to tables on previous pages See AD F Volumes 1 and 2 Appendix A for a full list of key terms Adjacent rooms may be considered as one room if there is a permanent opening(s) of at least 1/20th of the combined floor areas, in the dividing wall. See Vol 1 Diagram 1.3 and paragraph 1.29. Where a non-habitable space such as a conservatory adjoins a habitable room, the habitable room may be ventilated with opening(s) of at least 1/20th of the combined floor areas in both the dividing wall and the wall to the outside (see Volume 1 paragraph 1.29) both openings to have at least 10,000 mm2 background ventilation. Background ventilator A small ventilation opening designed to provide controllable whole dwelling ventilation – typically adjustable trickle ventilators or airbricks with hit-and-miss louvres located at least 1.75 m above floor level. Continuous mechanical extract ventilation Mechanically driven ventilation that continuously extracts indoor air and discharges it to the outside. Extract ventilation The removal of air directly from an internal space or spaces to the outside. Extract ventilation may be by natural means or by mechanical means (e.g. by an extract fan or a central system). PSV means passive stack ventilation operated manually and/or automatically by sensor or controller in accordance with BRE Information Paper 13/94 or a BBA Certificate. Passive stack systems are usually adequate for domestic-sized WCs, bathrooms and kitchens; since they have no fans or motors, they consume no energy and require no maintenance apart from cleaning. Duct sizes are typically 125 mm diameter

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or equivalent rectangular section. They need to rise vertically at least 2 m and preferably 3 m above inlets and can include only limited bends; they need to discharge via special terminals at or near roof ridges. An open flued appliance may be considered to provide ventilation if it has a free flue area of at least 125 mm diameter and is permanently open (i.e. no damper). However, if an open flued appliance is within the same room as an extract fan, this may cause spillage of flue gases so: Where a gas appliance and a fan are located in a kitchen, the maximum extract rate should be 20 l/s (72 m3/h). An extract fan should not be provided in the same room as a solid fuel appliance. Habitable room A room used for dwelling purposes but which is not solely a kitchen, utility room, bathroom, cellar or sanitary accommodation. Heat recovery Applied to mechanical supply and extract systems or a single room ventilator, extract air is passed over a heat exchanger and the recovered heat is put into the supply air. Highly airtight dwellings Dwellings that achieve one of the following. (a) A design air permeability lower than 5 m3 /(h·m2) at 50 Pa. (b) An as-built air permeability lower than 3m3 / (h·m2) at 50 Pa. Intermittent operation When a mechanical ventilator does not run all the time, usually running only when there is a particular need to remove pollutants or water vapour (e.g. during cooking or bathing). Intermittent operation may be under either manual or automatic control. Kitchens, utility rooms, bathrooms and WCs that do not have openable windows should be provided with an air inlet, for example, a 10 mm gap under the door.

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Kitchen extract ventilation ‘adjacent to hob’ means within 300 mm of centreline of hob and should be either a cooker hood or a fan with a humidistat. See Volume 1 Table 1.1 and Diagrams 1.1, 1.2. Mechanical ventilation with heat recovery A mechanically driven ventilation system that both continuously supplies outdoor air to the inside of the dwelling and continuously extracts indoor air and discharges it to the outside. For the purposes of this Approved Document, the guidance for mechanical ventilation with heat recovery applies to centralised or decentralised supply and extract systems, with or without heat recovery. Purge ventilation Manually controlled ventilation of rooms or spaces at a relatively high rate to rapidly dilute pollutants and/or disperse water vapour. Purge ventilation may be provided by natural means (e.g. an openable window) or mechanical means (e.g. a fan). Openings should have some part at least 1.75 m above floor level. Utility room A room containing a sink or other feature or equipment that may reasonably be expected to produce significant quantities of water vapour. Utility rooms that are accessible only from outside the building need not conform with the ventilation requirements of the Building Regulations. Whole dwelling ventilation (general ventilation) Nominally continuous ventilation of rooms or spaces at a relatively low rate to dilute and remove pollutants and water vapour not removed by extract ventilation, purge ventilation or infiltration, as well as to supply outdoor air into the dwelling. Source: Building Regulations–Approved Document F Volume 1 2021 edition.

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Heat reclaim vent systems MVHR – Mechanical Ventilation with Heat recovery HRV systems can be particularly appropriate for new, low energy, ‘airtight’ buildings and those with multiple extract needs or where passive systems are not feasible. They are essential for buildings designed to Passivhaus standards. Typically, multiple bathrooms, WCs, kitchens, etc. within a single occupancy have linked extracts powered by a single low speed (boostable) fan through a heat exchanger to preheat incoming replacement air that is delivered to circulation areas or main spaces, achieving heat reclaim efficiencies around 70%. In summer, airflow is diverted away from the heat exchanger. For a small house or flat, the central fan unit is typically the size of a small kitchen wall cupboard; flat or round section ducts can be located in floor, loft or partition voids. Heat exchange units need to be located for simple access to allow for regular cleaning/changing of filters. Cooker hoods and tumble dryers should not be connected directly to MVHR systems, unless via highly effective filters. For very low energy buildings without space heating systems, heating coils fed from a water-heating appliance can be incorporated in HRV systems to give a warm air back-up. Where duct installation required for centralised systems may not be feasible, individual MVHR fan units can be fitted in each room requiring extract ventilation, though these don’t have the air quality improvement benefits for whole buildings.

Extractor fans Sizing of fans The size of a fan should take into account the size of the room and not necessarily be the minimum required by Building Regulations.

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It therefore makes sense to calculate the size of fan needed by using the desired number of air changes per hour and relating them to the room size. Domestic Living rooms Bedrooms Bathrooms WCs Kitchens Utility rooms Halls and passages

Non-domestic 3–6 2–4 6–8 6–8 10–15 10–15 3–5

Cafés and restaurants Cinemas and theatres Dance halls Factories and workshops Commercial kitchens Offices Public toilets

10–12 6–10 12–15 6–10 20–30 4–6 6–8

Likely air changes per hour for typical existing situations To calculate the extract performance needed for a fan, multiply the volume of a room (m3) by the number of air changes per hour required (ACH): For example, domestic kitchen 4 m × 5 m × 2.5 m= 50 m3 air changes required: 12 50 × 12 = 600 m3/h one m3/h = 0.777 l/s one l/s = 3.6 m3/h To reduce energy consumption, it is desirable to restrict ventilation rates and use ‘extraction at source’ as far as possible, ideally controlled according to demand. Given effectively controlled ventilation, air changes in domestic living spaces and bedrooms can be reduced to below 1 – below 0.6 for Passivhaus standards – and maintain good air quality. For carefully built or refurbished buildings achieving high standards of air tightness, background ventilation systems including heat recovery can transfer up to 90% of the heat from exhaust air to incoming air.

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Siting of fans • Site fans as far away as practicable from the main source of air replacement that is usually the room door. • Site fans where there is reasonable access for cleaning and maintenance. • Fans in bathrooms must be sited out of reach of a person using a fixed bath or shower and must be kept well away from all sources of spray. • Insulate ducts passing through unheated roof spaces to minimise condensation. • Slope horizontal ducts slightly away from fan. Minimise duct lengths and use rigid ducts where possible with flexi ducts limited to final connections. • Vertical ducts, and ducts in roof spaces, should be fitted with a condensate trap with a small drainpipe to outside. • Refer to Approved Document F Volume 1:2021

Types of fans Axial fans are designed to move air over short distances, as through walls or windows. Centrifugal fans are designed to move air over long distances and perform well against resistance built up over long lengths of ducts. Sources: Vent-Axia Ltd www.vent-axia.com and Xpelair Ltd www.xpelair.co.uk

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Electrical installation Safety is paramount when electrical installation works are being carried out. Depending on the work being carried out, one or more of the following regulations need to be complied with: • BS7671:2018 + A2: 2022, also known as the IET Wiring Regulations, 18th edition • Building Regulation Part L • Building Regulation Part M • Building Regulation Part P

Electricity Electricity is sold by the unit. One unit is consumed at the rate of one kilowatt for one hour (kWh).

Comparative running costs of domestic appliances Most appliances have a colour-coded EU Energy efficiency label, showing energy efficiency ratings between A+++ and D; A+++ being the most efficient. The label also shows annual energy consumption in KWh/annum; there are also diagrams showing capacity water consumption and noise. Appliance

Time per unit

3 kW radiant heater 2 kW convector heater Iron Vacuum cleaner Colour TV 100 watt lamp 60 watt lamp 20 watt mini fluorescent 10 watt LED lamp Tall larder refrigerator

20 minutes 30 minutes 2 hours 2 hours 6 hours 10 hours 16 hours 50 hours 70 hours 63 hours

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Typical usage of larger appliances Chest freezer Dishwasher Cooker Hot water cylinder

kWh Per week One full load Per week for family of four Per week for family of four

5–8 1 23 85

Fuses – rating for 230 volt AC appliances Rating

Colour

Appliance wattage

2 amp 3 amp 5 amp 13 amp

Black Red Black Brown

Up to 450 460–650 760–1150 1260–3000

To find the correct amp rating of a socket for an appliance, divide the watts of the appliance by the volts (i.e. watts ÷ 230 = amps).

Guidelines to allocating (socket) outlets in domestic rooms The table below should be used as a guide and is not mandatory. Where quantities of outlets are recommended, they should be considered a minimum. Room

Socket Outlets

Entrance lobby Hall/landing Storage cupboard Lounge

1 No. 2-gang switched socket outlet 1 No. 2-gang switched socket outlet Switched fused spurs for equipment such as TV amplifiers, electric water heaters, etc. 4 No. 2-gang switched socket outlets Home technology requirements; e.g. wall-mounted televisions need sufficient power and located so that bracket and TV can be positioned appropriately. Power sockets with USB chargers in strategic locations

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Socket Outlets

Kitchen

1 No. 45 Amp cooker switch + outlet plate 4 No. 2-gang switched socket outlets 1 No. grid switch plate c/w switches controlling unswitched socket outlets for appliances such as extract hood, washer dryer, fridge freezer, dishwasher, extract fan, etc. Outlets for appliances 2 No. 2-gang switched socket outlets, with accessible switches if sockets below worktop 3 No. 2-gang switched socket outlets Switched fused connection unit for towel rail (depending on development) 1 No. shaver socket 2 No. 2-gang switched socket outlets. External Electric Vehicle charge point

Kitchen utility Bedrooms Bathrooms Garage

It should be noted that socket outlets alone do not make a complete electrical installation. Consideration will also need to be given to the following, on a room-by-room basis and designed in conjunction with other relevant trades (e.g. Home Technology Integrator): • • • • • • • • • • • • • • • •

Lighting (numbers of points, type of lighting) Lighting switching RF distribution (e.g. television outlets) BT master socket location Telephone outlets Data network outlets Home technology controllers (e.g. touchscreen) Surge protection especially for sensitive technology device locations Positioning of extra low voltage head end (ELVHE) – see Home Technology Integration Section Positioning of advanced lighting head Room thermostat(s) for heating Smoke/heat/carbon monoxide detectors Access control (depending on development) Positioning of the consumer unit Intruder alarm sensors Many of these controls can be provided as a wireless installation rather than hard-wired.

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Electrical installation graphic symbols

Source: BS 1192: Part 5: 2007

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Electric circuits in the home Typical domestic electrical layout

shr

s/h

fan

etr

T

2

2

master bedroom

2

bathroom

2

2 D

2

2

TV 2

T

2

2

T cpbd living / dining

2

db

2

2

hall 2

L

etr

2

utility

M fan

hwc

2

HRV

2

2

s/h

2

wc

2

2

h TV

2

T 2

kitchen

garage

2

EVC

T

thermostat door bell

M

motion sensor switch

L

light sensor switch

fan

ventilation fan

pendant light

etr

electric towel rail

data socket

HRV

EVC

s/h

fan

db

D

2

h

4 2

smoke and heat detector heat detector immersion heater

heat recovery ventilation unit

electric vehicle charging point as different symbols are often used, an explanatory key is usually included with the drawings

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Lighting Light creates the atmosphere that good architecture is viewed in.

Lighting the task Lighting levels are given below for the area in which a task is performed. This may a defined area on a workbench where local lighting or a task light can be provided to light the task area with the lighting level dropping off in the surrounding area. This is a good energy efficient way of providing light where it is needed and not where it isn’t. Only where there are no defined working areas, such as in an open plan office space with no pre-defined desk spaces, where it would be necessary to provide uniform lighting across the space. But even here it can be efficient to provide even background lighting of say, 200Lux and then provide a desk or local light to bring the lighting level on each desk up to the task level. In some areas, such as some factories tasks or art/graphics work, the task plane may be inclined or even vertical. For these tasks local or task lights may be used for fixed task areas or in areas with no defined task areas – such as art rooms where easels may be moved – fixed lighting that provides a good level of sideways flow of light across the space should be used. However, care needs to be taken to avoid light at high angles from ceiling lights that may be a source of glare. For many modern work areas good level of light on people’s faces are as important as light on a horizontal task plane. For this reason, good levels of vertical or cylindrical illumination are now recommended for many work spaces.

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1200 to 1600 mm zone above floor level where mean cylindrical illuminance should be > 150 lux with U > 0.1

Modelling ratio between task area illuminance and cylindrical illuminance 0.3 to 0.6

Task area illumination 300 to 500 lux

In domestic premises the lighting should designed to provide the user some flexibility in aiming if not positioning their lighting. For instance, downlights in ceilings should be of the adjustable type so that light can be directed towards furniture, art on walls or other features. Having layers of light in a domesticated environment helps to add interest to the space making it much more inviting and generally a more enjoyable place to be. Layering is how you create atmosphere in a room. It’s about combining different types of light to create a sense of depth. (Note, different types of light, but not different light. Kelvin colour matching is important when using different types of light fittings.) To achieve these layers of light, a good lighting design will make consideration to four types of lighting: • Task: As described already, this refers to increasing illuminance to better accomplish a specific activity. • Ambient: General illumination that allows us to see, as we live in the space. • Decorative: A lighting fixture that is meant to draw attention and add beauty or distinction to a room. • Accent: Lighting focussed on a particular area or object to highlight features of the room whether architectural or objects of interest like art.

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By providing separate control for each of these types of light, the function of a space and the atmosphere can be completely transformed. Intelligent lighting control can be a major benefit in achieving this by avoiding a multitude of confusing controls and replacing them with a single button to set a particular ‘lighting scene.’ (See Lighting Control section for more detail.) To provide a good visual environment the following illustration gives a guide to preferred rooms surface reflectance. Recommended lighting levels are also shown for walls and ceilings – levels below this will normally make the space appear gloomy and poorly lit. Effective wall reflectance = 0.5 to 0.8

Ceiling cavity reflectance = 0.7 to 0.9 Relative ceiling illuminance 50 lux

Relative wall illuminance 75 lux

Task illuminance 1.0

Effective floor cavity reflectance = 0.2 to 0.4

Window wall reflectance = 0.6

Daylight The primary purpose of a window is to provide light to enable a building to function. The function may demand high levels of light as in a workspace, but the level or intensity of light is of less importance than its quality. Daylight must first meet functional demands, but it must do much more than this: it must create a pleasant visual environment leading to a feeling of wellbeing, which in itself will stimulate individual performance.

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In modern buildings, good daylighting is a balancing act: on one side is the need for sufficient access to daylight and sunlight, and on the other is the need to control its unwanted effects. The design team need to work together to achieve this balance, exploring the options to arrive at a ­ satisfactory solution. For example, decisions about the amount of ­shading, whether or not it is adjustable, how to optimise the w ­ indow size, and whether or not air conditioning is required. Intelligent lighting controls (See Lighting Control section for more detail) can play an important role in helping to achieve this balance. These allow shading solutions to operate automatically providing protection as the sun moves around the building, helping to keep buildings cool as well as protecting interiors from ‘bleaching.’ They also offer other benefits such as simulating occupancy of a vacated home and avoiding potentially hazardous or unsightly operating cords. There are three main drivers for improving the daylighting of buildings: • energy consumption: Making use of available daylight could mean the electric lighting could be switched off or dimmed to save energy by using automatic lighting controls. • benefits to human health and wellbeing: We are ­gaining more understanding about the positive benefits on ­human physiology and psychology that daylight provides, with daylight being an essential component in regulating the circadian system or body clock and sleep wake cycles. • appearance of the space: Most people have a preference for daylit spaces with a view to the outside. Daylight in buildings has a special quality that electric lighting doesn’t have. • for detailed guidance see LG10 ‘Daylighting – a guide for designers,’ by the Society of Light & Lighting.

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Regulations covering lighting Part L All lighting installations need to incorporate an element of energy efficient lamps to comply with Building Regulations Part L. Below is a summary of conditions to ensure compliance: Part L1.  Dwellings Each Internal light fitting should have lamps with a minimum luminous efficacy of 75 light source lumens per circuit-watt • Internal fittings should have controls to allow for separate control of lighting in each space or zone. Controls may be manual, automatic or a combination of both. • External lighting should have both of the following controls: a. Automatic controls which switch luminaires off in response to daylight. b. If luminous efficacy is 75 light source lumens per ­circuit-watt or less, automatic controls which switch the luminaires off after the area becomes unoccupied. If luminous efficacy is greater than 75 light source lumens per circuit-watt, manual control is acceptable. Part L1B. Same requirements as Part L1A subject to the following work being carried out: • A dwelling is extended • A new dwelling is created from a material Change of Use • An existing lighting system is being replaced as part of the re-wiring works. Part L2.  Non-Dwellings Any fixed lighting should achieve levels of illumination appropriate to the activity in the space. Lighting should be designed based on CIBSE’s SLL Lighting Handbook or an equivalent guide.

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Lighting should observe the following. General lighting to have an average luminaire efficacy of 95 luminaire lumens per circuit-watt Display lighting to have an average luminaire efficacy of 80 luminaire lumens per circuit-watt Both general and display lighting should be metred. Unoccupied spaces should have automatic controls to turn general lighting off when the space is not in use. Occupied spaces should have automatic controls suitable for the use of the space. General lighting in occupied spaces should have daylight controls for parts of the space which are likely to receive high levels of natural light. Display lighting should be controlled on dedicated circuits than can be switched separately from those providing general lighting. Part L2B. Same requirements as Part L2A but only applicable to those areas affected by building works. The latest version of Part L of the building regulations which came into effect on 15th June 2022 (check for updates) has the lighting requirements contained within 2 x volumes rather than the previous 4 volumes. Volume 1 is for Dwellings. Volume 2 is for Buildings other than dwellings. Volume 1 Dwellings Volume 1 requires the efficacy of all fixed lighting >80 lumens / watt. Where lighting is installed in new or existing dwellings, internal light fittings should have local controls to allow for the separate control of each space or zone. Controls may be manual, automatic or a combination of both.

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Any fixed lighting should achieve illuminance levels appropriate for the activity within the space and not over illuminate. Where homeowners can choose their own lamps, lamps should have a minimum efficacy of 75 light source lumens per circuit-watt. Where installed in a new or existing dwelling, fixed external lighting should have both of the following controls. a. Automatic controls which switch luminaires off in response to daylight. b. If luminous efficacy is 75 light source lumens per circuit-watt or less, automatic controls which switch luminaires off after the area lit becomes unoccupied. If luminous efficacy is greater than 75 light source lumens per circuit-watt, manual control is acceptable. Volume 2 Buildings other than dwellings Any fixed lighting should achieve levels of illumination appropriate to the activity in the space. Spaces should not be over-illuminated. Lighting should be designed based on CIBSE’s SLL Lighting Handbook or an equivalent design guide. For smaller spaces where total lighting power is likely to be low (toilets, store rooms etc.) there is no expectation that lighting calculations should be produced. Lighting should observe the following. a. If it is general lighting, either: i. have an average luminaire efficacy of 95 luminaire lumens per circuit-watt ii. the Lighting Energy Numeric Indicator (LENI) method, following Appendix B.

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b. If it is display lighting, any of the following: i. have an average light source efficacy of 80 light source lumens per circuit-watt ii. have a rated power usage no greater than 0.3W/m2 in each space iii. the LENI method, following Appendix B. c. For high excitation purity light sources, an average light source efficacy of 65 light source lumens per circuit-watt. General lighting and display lighting should be metred by one of the following methods. a. Dedicated lighting circuits with a kWh metre for each circuit. b. Local power metre coupled to or integrated in the lighting controllers of a lighting management system. c. A lighting management system that can both: i. calculate the consumed energy ii. make this information available to a building management system. Lighting controls in new and existing buildings should follow the guidance in the Building Research Establishment’s Digest 498. Unoccupied spaces should have automatic controls to turn the general lighting off when the space is not in use (e.g. through presence detection). Occupied spaces should have automatic controls where suitable for the use of the space. General lighting in occupied spaces should have daylight controls (e.g. photo-switching and dimming) for parts of the space which are likely to receive high levels of natural light. Display lighting should be controlled on dedicated circuits that can be switched separately from those for lighting provided for general illuminance. While the legal requirements for lighting are similar throughout the UK, each country has its own Building Regulations.

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Fire rating When installing lights that penetrate the ceiling you need to consider that cutting a hole in the ceiling plaster to install the light may create a route for fire spread between floors if the ceiling was providing a fire barrier. Fire-rated lights or ordinary lights with well fitted intumescent fire covers, should be used to maintain the fire integrity of a ceiling and to ensure air leakage and heat loss between floors and roof spaces of a dwelling is minimised.

Emergency lighting In many premises some form of emergency lighting is needed to allow occupants to leave safely in the event of a mains power failure. For some building types, such as places of public assembly and those where people sleep overnight other than single family homes, there is a legal requirement to provide emergency lighting. In other premises it is for the building owner or operator to carry out a risk assessment to determine if an emergency lighting system is needed. There is usually a need to provide directional signs throughout a building with emergency lighting to guide occupants to the nearest final exit door from the building and then even to an exterior place of safety. Emergency lighting is a system of lights that are powered from a central battery located in a plant or store space, or from batteries built into each light. For large buildings it is normally more economic to provide a central battery system but in small buildings lights with self-contained batteries are normally more economic. Test switches or controls are needed to allow for periodic testing of the emergency lighting by the building owner or operator, with a daily visual, monthly short duration and annual full rated test being the requirement.

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Emergency lighting levels Corridors and stairs – Minimum design value of 1 lx on the floor along the centre line of the route with 0.5 lx on the floor of the centre band of at least 50% of the route width. Open escape areas – Minimum design value of 0.5 lx on central core empty floor excluding 0.5 m wide perimeter band Disabled refuges – 5 lux at floor level. Luminaires should be located at level changes, direction changes, corridor intersections, stairs and ramps. Fire fighting equipment such as call points and extinguishers should be directly lit by emergency lighting. Fixed seating areas – Minimum design value of 0.1 lx on a plane 1 m above floor/pitch-line over seated areas. Gangways should be treated as clearly defined routes High risk task areas – Minimum 10% of maintained illuminance on the reference plane but at least 15 lx For detailed guidance see LG12 ‘Emergency Lighting,’ by the Society of Light & Lighting.

Lighting controls Lighting controls can be used to control more than just the electric lighting. They can incorporate control of any piece of technology that has been integrated with the control system (see Home Technology Integration section) including audio visual systems, security, heating and ventilation as well as blinds, shutters & shading associated with windows and day light ingress. A significant aesthetic (as well as functional) benefit can be achieved when other technology is integrated as there is no longer need for a multitude of separate controls for each technology to clutter up the wall.

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The control itself can take many forms: • Manual switching or automatic controls • Dimming and/or switching of luminaires from multiple locations (including away from home) for mood or lighting performance • Dimming and/or switching of luminaires for energy reduction • Changing colour temperature/output level of light sources for effect or wellbeing • Bi-directional communication with individual luminaires to monitor performance and to initiate automatic test/feedback sequences • Buttons, switches and even touch screens in a wide variety of finishes • Interfacing with other systems (e.g. fire alarms, A/V systems, BMS or local HVAC control) Given the wide range of product options, control strategies and outcomes possible in the specification of a lighting control system, it needs a consultative approach between all project stakeholders from the early stages of architectural design through to services design, to ensure that the performance objective for the lighting control system is defined and understood and then designed, specified, installed, commissioned and handed over according to the agreed requirements. Lighting control technology continues to evolve at a remarkable pace and although the starting point for simple lighting installations is still manual switches or individual dimmers for each circuit in an area, there is an increasing popularity for ‘intelligent’ or advanced lighting systems that enable many of the control features mentioned above. These advanced lighting systems can control the whole house (and garden) or remain limited to key areas such as open plan multi-use areas where they offer particular benefit. The August 2014 update to VAT Notice 708 (Building and Construction) from HMRC confirmed that central controls for light, heat and ventilation, including intelligent lighting systems,

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have been added to the list of ‘ordinarily’ incorporated items in dwellings. This small change highlighted a significant shift in the thinking around lighting control systems in residential development. What this means is that where a new build or renovation is eligible for a reduced rate of VAT, any lighting controls installed may also be eligible for a reduced rate. This makes lighting controls more affordable in a residential context. When designed and installed properly, lighting controls can make a well-designed lighting scheme easier-to-use, energy-efficient and contribute to improved home security. For detailed guidance see LG14 ‘Control of electric lighting’, by the Society of Light & Lighting.

Lighting glossary Colour rendering The ability of a light source to render colours naturally without distorting the hues Colour rendering index (CRI) An index based on eight standard test colours where the unit is Ra. Ra100 is the maximum value. Ra80 and above is considered appropriate for normal activities in offices, factories, schools, etc. For work needing better colour discrimination, such as shops and hospitals, values over Ra90 are recommended. Compact fluorescent lamp Small scale fluorescent lamps, often with integral gear, for long life low energy use in small fittings. Correlated colour temperature (CCT) The colour appearance of light, determined from its colour temperature given in degrees Kelvin. The lower the figure the

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warmer the light. Less than 3300 K is warm (red); 3300–5300 K intermediate and more than 5300 K cold (blue). Cylindrical illumination Total luminous flux falling on the curved surface of a very small cylinder located at the specified point divided by the curved surface area of the cylinder (unit: lx) Discharge lamp A lamp that produces light from an electrical discharge passing through a glass containing vapour or gas. Efficacy The ratio of initial lumens emitted from a lamp divided by its consumption of power in watts (lm/W). Emergency lighting Low output battery or generator powered lighting for escape purposes when mains power fails. Flood A lamp designed with a wide beam. Fluorescent tube A tubular lamp, with blue/violet light being produced internally via a discharge through generally argon and low pressure mercury vapour. It has a phosphor coating on the inside of the tube that converts (fluoresces) some of this light to other colours to make a white light. GLS (General Lighting Service) lamp Other name for standard tungsten-filament lamps.

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Halogen lamp An incandescent lamp filled with low pressure vapour of iodine or bromine. Sometimes referred to as tungsten-halogen. HID (High Intensity Discharge) lamps A lamp that produces light from an electrical discharge passing through a glass containing vapour or gas that is, metal-halide, mercury and sodium lamps. Illuminance The amount of light falling on a surface. The unit is lux which is one lumen per square metre (lm/m2). Incandescent lamp A tungsten filament enclosed in a glass envelope either under vacuum or filled with inert gas so that it can be electrically heated without burning out. Incandescent means luminous or glowing with heat; as a result, can it is an inefficient light source emphasising reds, yellows and greens while subduing blues. Initial lumens The light output of a lamp measured after one hour for incandescent lamps and 100 hours for fluorescent and discharge lamps. Lumens quoted in manufacturers’ catalogues are ‘initial’ lumens. LED LEDs are ‘solid state’ emitters of coloured light made from similar materials (semiconductors) to those used to manufacture electronic integrated circuits. They produce light by a very different method to incandescent, fluorescent or discharge lamps and do not require heat or high voltages to operate. An LED ‘die’ which typically measures just 0.25 × 0.25 mm,

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is encapsulated into a solid resin to produce an individual LED component with connecting leads. Light-Loss Factor (LLF) The loss in light output from a luminaire due to dirt on the lamp or fitting. Now more normally referred to as maintenance factor. Light Output Ratio (LOR) The ratio of the total light emitted by a luminaire to the total output of the lamp(s) it contains – which is always less than unity. Lumen (lm) The unit of luminous flux used to measure the amount of light given off by a light source. Luminaire A light fitting. Luminance The brightness of a surface in a given direction, measured in candelas per square metre (cd/m2). Luminous flux The flow of light energy from a source, or reflected from a surface, standardised for the human eye and measured in lumens. It is used to calculate illuminance. Lux The unit of illuminance measured in lumens per square metre (lm/m2). Bright sunlight is 100,000 lumens; full moon is 1 lux.

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Maintained illuminance The minimum light level over an area immediately prior to cleaning/re-lamping. Maintenance factor The proportion of initial light output from an installation after some specified time. Metal-halide lamps High pressure mercury discharge lamps with additives which can vary the light appearance from warm to cool. Rated Average Life (RAL) The time by which 50% of lamps installed can be expected to have failed. Sodium lamp (SON) A highly efficient lamp with a warm yellow light, used mainly for street and flood lighting. It has poor colour rendering, with the low pressure (SOX) types making all colours except yellow appear brown or black. Spot (S) A lamp producing a narrow beam of light as opposed to the medium/wide beam of a flood. Task area Area within which the visual task is carried out Tri-phosphor lamp A fluorescent lamp with good colour rendering. Tungsten-filament lamp an incandescent lamp. Vertical

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Lighting: levels and colours Comparative light levels

lux

Bright sunlight Worktop or desk near window Full moon on clear night

100 000 3 000 1

Recommended lighting levels Houses/Flats/bedsits Entrance lobbies Lounges Kitchen Bathrooms WCs

lux

Communal Areas Main entrances Corridors Staircases Lounges TV lounges Quiet/rest rooms Dining rooms Laundries Stores

100 150 150–300 150 100 200 20–100 100 100–300 50 100 150 300 100

Colour temperatures

K

Blue sky Uniform overcast sky Average natural daylight Fluorescent cool white lamp Fluorescent warm white lamp LED cool white lamp LED warm white lamp Halogen filament lamp GLS tungsten filament

10 000 7 000 6 500 4 000 3 000 4 000 3 000 3 000 2 700

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CIE CRI Ra 100 90 80 60 40

CIE Group Where accurate colour matching is required, e.g. specialist printing/textile inspection, Where good colour rendering is required, e.g. shops, art/craft work Where moderate colour rendering is acceptable e.g. offices, homes Where colour rendering is of little significance but marked distortion unacceptable e.g. heavy manufacturing Where colour rendering is of no importance

1A 1B 2 3 4

Lamp types Below is a listing of the main types of lamps available. Specialist lamps, such as those used in instrumentation, horticulture, entertainment, etc. are excluded. Manufacturers’ catalogues should be consulted for more information on available lamp ranges. Lumens quoted are for Initial lumens. The lowest values have been given, which are for pearl or opal versions of a lamp or the ‘warmer’ colour temperature LED or fluorescent lamps.

LEDs (Light emitting diodes) In an LED lamp, an electrical current is passed across semiconductor (usually silicon) material. As electrons migrate between charged atoms in the semiconductor, photons of light are released. LED lighting is the most efficient type of lighting system currently available. Technological advances, continuing cost reduction, and rapid product innovation and diversity make it almost inevitable that LEDs will be the predominant form of lighting in the near future. They are highly efficient and many offer over 100 lumens per watt, though note that some products may be

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only marginally more efficient that the better CFLs. In addition, they have very long lifetime expectancy and superior switching frequency resistance, typically averaging around 35,000 hours and 30,000 switches. LED lighting is now available for almost every domestic lighting purpose. LED lighting is available that can be fitted into traditional pendant light fittings containing bayonet, cap or Edison screw lamp holders. Downlights, traditional ‘bulb’ shaped, linear tube type and candle style lamps are all available. It is recommended that only dedicated LED luminaires and control gear (especially dimmer switches) are specified for LED lamps. When using LEDs as replacements there can be operational issues associated with existing transformers and dimmer switches, and these should be replaced with LED-compatible electronics. Positives: • energy efficiency class A+ • low running costs – significant lifetime cost savings • long lamp lifetime: 30,000+ hours or more predicted for many products • wide range of colour temperature 2,700–6,000 • good colour rendition available • minimal heat output • wide range of lumen outputs/beam angles Negatives: • higher purchase price (but prices falling rapidly) • variation in quality and performance (though this is improving) • for dimming, specific circuits and lamps must be specified. LED – key issues to consider when specifying 1. Lumen output 2. Luminous efficacy (lumen output per watt of power used)

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3. Lumen maintenance and rated life 4. Colour temperature (this may be expressed as a CCT measure) 5. Colour rendering (CDI index) 6. Operating temperature Although most modern lighting will employ LED light sources for the majority of applications, it is worth mentioning some of the other more common light sources still available, though the use of these is likely to dwindle over time.

Fluorescent lighting Inside a fluorescent lamp or tube an electrical charge is passed through mercury gas. This generates UV light, which then excites a phosphorescent coating on the inside of the tube to generate visible light. There are two main types of fluorescent lighting: compact fluorescent and linear fluorescent. A ballast is needed for fluorescent lighting to supply a suitable amount of current for start-up: this can be incorporated into the bulbs design or can be an attachment on the lighting fixture. Good quality fluorescent lighting complies with current Building Regulations. Fluorescent lighting is very energy efficient, and offers long service life. It has been associated with cool light and slow start-up times. However, advances in fluorescent lighting have led to a range of products which are satisfactory in many domestic situations. Fluorescent lamps are manufactured in two distinct types: linear fluorescent lamps (LFLs) and the more recent compact fluorescent lamps (CFLs).

Linear florescent lamps (LFLs) LFLs are the familiar ‘light tubes,’ which have been in common use from the 1960s. They typically produce very bright light. In domestic settings this has made LFLs popular for task lighting

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in kitchens (e.g. under cabinets), in home offices, utility rooms and bathrooms (e.g. along a mirror). Unlike CFLs (see below) LFLs do not have integrated ballasts, and require a dedicated fitting. While this form of lighting is energy efficient, LED equivalents are available in tubular form, so can be a ‘like for like’ alternative to LFLs. Positives: • energy efficiency class A • low running costs • long life time 20,000 hours+ • range of colour temperatures 2,700K–6,000K Negatives: • must have ballast/ control gear in fitting • contain mercury and must be disposed of carefully • not dimmable

Compact fluorescent lighting (CFLs) CFLs are highly energy efficient (usually class A) and are a good choice for areas requiring long periods of lighting, for example living rooms, stores, toilets; however, it is clear that LED alternatives are now offering even greater advantages. Both CFLs (and dedicated fittings for CFLs) are available in a wide range of sizes, shapes and colours. Some CFLs are suitable for dimming but require compatible control gear and dimmers. Take care not to select CFLs that are overly large in size or unsuitable for the shade, enclosure or location in which they will be installed. Positives: • normally energy efficiency class A • low running costs

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• long life time 8,000–15,000 hours • wide range of colour temperature 2,700K–6,000K. Negatives: • short warm-up time needed • contain mercury and must be disposed of carefully • not suitable for dimming using pre-existing ‘standard’ domestic dimmer switches. When specifying CFLs, look for the following characteristics: • • • • • • • •

minimum lamp lifetime of 10,000 hours lumen maintenance of >76% at 10,000 hours colour rendering index not less than 80 CRI power factor not less than 0.9 colour temperature of 2,700K luminous efficacy >55 lumens per watt minimum 35% lumen output 2 seconds after switching on minimum 80% lumen output 60 seconds after switching on.

A note about mercury content CFLs do contain small amounts of mercury but below legal limits – only 3–5 milligrams. Care should be taken when fluorescent light bulbs are broken however, with disposal carried out in line with manufacturer’s recommendations.

Tungsten-halogen Halogens are incandescent lamps using a filament suspended in a small amount of halogen (iodine or bromine) gas. They are smaller than the equivalent incandescent lamp; work at a higher temperature and are marginally more efficient. Halogen lamps produce an attractive bright white light, reach full lighting level immediately and can last from 1,000 – 3,000+ hours. However, the majority of halogen lamps, including

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those within the newer eco-halogen category, do not meet the 46 lumen/circuit-watt requirement for low energy lighting in Part L of the Building Regulations. Halogens were most commonly used for downlighting, but their high energy consumption and relatively short service life mean that they are being superseded by equivalent LED lamps. Even the best halogen lamps have efficacy ratings and service lives which are well short of the performance offered by CFLs and LEDs, however if considering halogens, select for lamp life, some offer 3000-hour life, and select energy class B or above. Positives: • low purchase price • colour temperature: good, although limited to around 3000K • colour rendering: excellent (CDI near to 100) • no warm-up time • easily dimmable. Negatives: • mainly energy efficiency class C – not rated as ‘energy efficient’ under Building Regulations • high running costs • short lifetime: 2,000 hours typical • very high surface temperature.

Incandescent/tungsten/GLS lamps All but specialist use lamps in this category have now been withdrawn from sale within the EU due to very high energy use. For further general advice on this lighting topic see ‘The Lighting Handbook,’ produced by the Society of Light & Lighting. For detailed technical information see ‘The Code for Lighting,’ also by the SLL. https://www.cibse.org/society-of-light-and-lighting

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Sound Sound Level and Frequency Sound is perceived both in terms of its loudness (level) and pitch (frequency). Sound level is measured in decibels (dB), with the range 0dB to 140dB representing the threshold of hearing to the threshold of pain. The decibel is a logarithmic scale, with a 10 dB increase being a 10-fold increase in energy, although this is generally perceived as a doubling in loudness. For normal hearing, the audible frequencies are between 20 Hz bass to 20 kHz treble (middle C on a piano is 262Hz). The ears sensitivity is greater at higher frequencies. However, as we age our hearing degrades, particularly at the higher frequencies. Below are example noise levels (source: noisehelp.com) for various sources in terms of dBA. This is a single figure value, which takes into account our perceived sensitivity to the frequency spectrum of the sound source. Noise

Source dBA

• • • • • • • • • • • • • • •

140 130 120 110 100 90 80 70 60 50 40 30 20 10 0

jet engine at takeoff peak stadium crowd noise thunderclap rock band hand-held drill lawn mower alarm clock shower conversational speech light traffic babbling brook whisper rustling leaves a pin dropping healthy hearing threshold

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Sound insulation Sound insulation is the ability of a material or structure to resist the passage of sound. There are two types of sound insulation in buildings: airborne and impact. Airborne sound insulation is the attenuation of airborne noise (sound transmitted through air e.g., speech, music) between adjoining rooms or from the outside to inside, whereas impact sound insulation is the ability of a structure to reduce noise transmission generated by direct physical excitation, for example, footsteps on a floor. Airborne and impact noise can travel by two routes; through the separating structure itself (direct transmission), and indirectly via adjacent common building elements (flanking transmission). Flanking paths will typically limit the overall sound insulation achievable, and can in some cases seriously degrade the sound insulation of the partition/floor. The factors determining the attenuation of airborne noise are: • Mass: the greater the mass the higher the airborne sound insulation; according to the mass law there will be approximately a 5 dB increase in sound insulation per doubling of mass for a solid element. • Isolation: Constructions with a cavity, such as lightweight stud walls, provide sound insulation due to the separation of the two leaves. This helps reduce the transmission of structural vibrations that cause the sound to radiate in the adjoining room. Larger cavities and the use of discontinuous constructions, for example, double stud walls, will increase the isolation with a corresponding increase in the sound insulation achievable. The mass of the separating leaves is still important but the resulting airborne sound insulation of the construction is significantly higher than the overall mass would suggest. Dense mineral fibre of up to 50mm contained within the cavity will further increase the sound insulation of the construction.

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• Sealing: It is imperative that there are no gaps in the construction, as even a small gap can lead to a marked deterioration in the acoustic performance (an analogy is a bucket with a hole in will leak water regardless of the thickness of bucket’s sides). Joints between walls and ceilings must therefore be sealed with tape or caulked. • Flanking transmission: indirect noise paths via elements common to adjacent spaces, such as an external wall or an interconnecting ventilation duct, must be carefully considered in order to minimise flanking. The method to mitigate the flanking route will vary, but in principle it will consist of providing isolation where possible (i.e., providing a break in the element between the spaces or introducing independent linings) and/or increasing the sound insulation of the flanking element (e.g., cross talk attenuator fitted to the ventilation duct). • Volume & area: The common area of the separating wall/floor and the volume of the receiving room will also influence the level of sound transmitted to the receiving room. Below are single figure weighted sound reduction values (Rw) for example building components. Material

Rw dB

• • • • • • • • • •

25 29 33 39 45 45 47 49 50 50

One layer 9.5 mm plasterboard 4/12/4 mm double glazing 10/16/6 mm double glazing Lightweight concrete block, plastered both sides 2 × 12.5 mm plasterboard either side of 70mm metal C stud 110 mm brick, plastered both sides 150 mm dense concrete block 10/200/6 mm secondary glazing 230 mm brick, plastered both sides 2 × 12.5 mm plasterboard either side of 70 mm metal C stud with 50mm dense mineral fibre contained within the cavity • Double metal stud with 137 mm total cavity containing 50 mm dense mineral fibre, 2 × 15 mm dense plasterboard as outer leaves

62

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Due to the contribution of flanking routes, and the influence of the area of the separating element and receiving room volume, the resultant room-to-room weighted sound level difference (Dw) will usually be lower than the Rw sound reduction value for the separating partition/floor itself. As a rule of thumb, the sound reduction performance of a separating element should therefore be at minimum 5dB greater than the desired airborne sound level difference between the spaces; this assumes that flanking routes have been minimised. Impact sound insulation is an important consideration when dwellings are separated by a floor. The ability of a floor to reduce impact noise transmission is highly dependent on the isolation provided within the structure. Typically, a floating floor utilising a resilient layer and/or suspended ceiling is required. These will reduce the vibration transmission of the impact noise through the structure, thereby increasing the impact sound insulation performance. Careful detailing is required to ensure that any resilient layer is not bridged, particularly around the perimeter of the floor. Approved Document Part E (AD E) of the Building Regulations provides minimum airborne and impact sound reduction performance values for both residential conversions and new builds. For airborne noise the requirements are given in terms of DnT, w+Ctr; this equates to the room-to-room weighted sound level difference (Dw), noramlised to a 0.5 second reverberation time (nT) and with a noise source spectrum correction applied (Ctr). For impact sound insulation the requirements are given in terms of L’nTw. Note that for airborne sound, the higher the DnT, w+ Ctr value, the better the sound insulation, whereas for impact sound insulation, the converse is true; the lower the L’nTw value the better the impact sound insulation. To demonstrate compliance with AD E requirements, pre-­ completion sound insulation tests are required unless field tested Robust Details (www.robustdetails.com) have been employed.

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For schools the Department for Education’s Building Bulletin 93 (BB93) provides minimum sound reduction values between spaces in terms of DnT, w.

Sound absorption and reverberation time The ‘reverberation time’ (RT) of a space describes the length of time for a sound, if abruptly stopped to decay by 60dB. In highly reverberant spaces, such as in a church, sounds do not decay quickly; this results in a gradual build-up of noise as new sounds are heard against a background of decaying earlier sounds. The RT in a room is proportional to the room volume divided by the total acoustic absorption. Acoustic absorption is a measure of the energy absorbed when the sound wave is incident upon the surface compared to that reflected. If all the energy is absorbed and none reflected, that surface or material has an absorption coefficient of unity. Absorption coefficients are measured and presented in octave bands as (usually) materials as absorption is frequency dependent. For example, a carpet on concrete floor will absorption very little at low frequencies but will be effective at high frequencies. The acoustic absorption performance of a material is often rated in terms of its Absorption Class. These range from A (provides the highest absorption) to E with a further unclassified rating for reflective materials. If only a moderately absorbing product is used (e.g., Class C) then a greater material area is required to achieve the same effect as a better performing treatment. The RT can be too long where the surfaces of a room are predominantly hard (and therefore highly acoustically reflective), which is often the case in modern open plan living, workspaces and communal areas. With the introduction of dedicated acoustic absorbers, such as fixed wall or suspended ceilings panels, the RT can be

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reduced. The amount of acoustic absorption required will depend on the desired RT, the volume of the room, and the performance of the absorber. It should be highlighted that environmentally sustainable sheep’s wool acoustic absorbers are now available. Internal noise levels The noise level within a room will have a bearing on the resting/sleeping conditions, acoustic privacy, speech intelligibility and the ability for work or study requiring concentration. Depending on the room’s usage the internal noise level is therefore an important consideration for the designer. Below are examples of guidance unoccupied internal noise limits (i.e., the level without the contribution of the occupiers’ own activities) for various room uses (source: BS8233:2014 and BB93). These limits, which are provided in terms of the ‘average’ noise level (L Aeq), generally apply to steady noise sources, such as road traffic noise ingress or mechanical services. The noise ingress limits are to be achieved with windows closed and trickle vents open (as required for ‘background’ ventilation). Space

L Aeq dB

• • • • • • • •

40–55 45–50 40–45 40–45 35–40 35 35 (day) and 30 (night) 40

Restaurant Open plan office Libraries Science laboratory General classrooms Living rooms Bedrooms Dining rooms

If the external noise source is commercial/industrial, lower noise ingress limits may be warranted that take into account the nature and character of the noise. BS4142:2014+A1 2019 provides an assessment methodology to review the potential noise impact of commercial/industrial noise sources.

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Maximum noise events during the night period should also be considered, with L Amax, F 42–45dB typically not to be exceeded in order to avoid potential for sleep disturbance. Unless mechanical ventilation is provided, ‘purge’ ventilation in relation to overheating may require open windows. It is generally accepted that there is a compromise between providing rapid ventilation via an open window and the unavoidable higher noise ingress levels (a façade with an open window provides around a 13dB reduction between outside to inside). For this situation ‘Acoustics Ventilation and Overheating – ­ esidential Design Guide: 2020’ advises that ‘reasonable’ inR ternal conditions may be considered to be noise ingress levels up to 5dB above BS8233’s noise ingress limits. Approved Document Part O of the Building Regulations however advises that during the night (23:00–07:00hrs) windows are likely to be required to be closed if the external noise level exceeds L Aeq,8hr 40dB and/or the maximum noise level is greater than L Amax, F 55dB more than 10 times a night. Depending on the external noise environment, alternative means of providing ventilation to mitigate against overheating may therefore need to be considered.

Home technology integration Introduction The development of technology has transformed the world we live in and is changing the way we both design and live in our ‘connected homes.’ Although there is no single definition of a connected home, it can be thought about as a home in which technology enhances the lives of those who live in it. Typically, it includes at least some of the following: • Data networks that provide the distribution of broadband, television and telephone etc.

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• Integrated heating controls to simplify operation while optimising user comfort and energy consumption. • Home automation that provides control (whether at home or remotely) of audio, video, lighting, motorised blinds/curtains, central heating and much more. • Advanced lighting to potentially control both artificial light as well as natural daylight using blinds/curtains to create a scene-setting system whilst reducing energy consumption. • Discreet whole home audio systems that offer a room-byroom listening experience without potentially unsightly hi-fi components and cumbersome speakers. • Audio and video storage/playback systems to allow movies and music to be shared and streamed throughout the home. • Home cinema (or Media Room) design and installation with technology integration. • Integrated security, door entry and intercom systems that deliver the highest level of safety and convenience. The focus on providing services in residential construction has been increasing for many years. Central heating, once considered a luxury, is now a standard feature in almost all new homes. Integrating a level of home technology should be considered for all builds and renovations in the same way as we do with other services such as electrics, plumbing etc. Virtually all homes will have a requirement for some level of technology, even if that is just a basic television and a reliable internet connection. Retrofitting good, reliable home technology to an existing home is significantly more costly than including the correct infrastructure in a new or renovated home due to the complications of routing wires and placing technology in appropriate places. The visual aspects of retro-fitted cabling can also detract from the perceived value of the home. At the simplest level architects can enhance the value of their building by incorporating sufficient wiring to provide a basic infrastructure.

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Most customers invest in home technology solutions for benefits like saving energy, adding safety and the simplicity that automation can bring; not for the sake of owning technology. Homes with automated systems also have the potential to sell for much more than comparable homes with conventional technologies. Automating a home can be a worthwhile investment in increasing its market value and attracting possible buyers in the future. In the same way that a heating/plumbing engineer is engaged to design, install and often maintain the central heating, there are also specialists for the design, installation and maintenance of home technology known as Home Technology Professionals by CEDIA. CEDIA is the international trade organisation for the home technology industry with nearly 4,000 member companies worldwide and certified professionals can be found by using the CEDIA website.

Considerations Here are some general considerations that will be relevant to almost all architect projects: Engage the Home Technology Professional at the early stages of project design • Significant value is often achieved through the integration of other services such as lighting and heating and the home technology solution may have a bearing on the design of these other services which, if considered early on, often has little or no impact on cost. • Homeowners often want to keep their technology installation discreet with the use of in-wall/ceiling products etc. which can influence how walls and ceilings are constructed. For example allowing ceiling joists to run in a certain direction to allow an in-ceiling projector screen to be mounted. • The Home Technology Professional is likely to work with many of the trades involved in a build or renovation.

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Allow for a suitable location and space in the design to locate the central hub1 described in the section below. • Exact requirements will depend on the scope of an installation; however, allowing for a space from floor to ceiling that is 600 mm wide and 750 mm deep should be adequate for many installations. • Technology equipment such as satellite boxes, amplifiers, etc. are often located in this central hub to reduce clutter of technology in rooms across the house and facilitate distribution of services. • Depending on the equipment located in the central hub, consideration needs to be given to ventilation requirements and the sound generated by the equipment fans. Essential requirements of the home technology solution include good wireless coverage and provision of some wired connections • Even though wired connections are normally faster and more secure, wireless connections form a key part of a home network. Many older homes can struggle to provide a good wireless signal throughout, but certain modern construction materials, for example, steel framing and foil backed plasterboard, can also limit the transmission and performance of Wi-Fi. • The router should be connected as close to the incoming BT master socket as possible but if this includes your Wi-Fi, this is unlikely to provide optimal coverage so alternative solutions are often required. • Consider the inclusion of some wired connections to be business-as-usual; correct cabling will add value to the home by providing flexibility to help meet future buyers’ home technology needs. • Some basic wiring can eliminate many of the Wi-Fi issues described above; a wired connected home will include three elements: °° Cables for incoming services (broadband, telephone, digital terrestrial TV, satellite or cable TV, FM or DAB radio, etc.)

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°° A central hub where the incoming services meet °° Cables from the central hub to distribute/integrate services throughout the home (and in some cases garden). It is important that mains outlet requirements are considered in conjunction with the positioning of the coaxial and data outlets in each room. Ensure options are available for the routing of cables • Given that cables will be routed to this central hub location from across the home any consideration to simplify (and therefore reduce installation cost) the routing of cables is beneficial. For example, a basic riser ‘duct’ between floors. Low voltage and extra low voltage cabling requires some special consideration when being run around the property. Due to the type of signals they carry, they are susceptible to interference from mains and high voltage cabling. That is, they should not share the same cable routes.

Note 1 Sometimes referred to as the ‘extra low voltage head end’ or ELVHE.

5 Building elements Enclosure Building elements include those very basic to architecture and construction – walls, floors and roofs – all of which are fundamentally about separation – originally separating people from weather, animals and other people but then acquiring – ­perhaps due to their very scale and cost – other qualities such as aesthetics, cohesiveness, prestige and cost-effectiveness. The varieties and number of these are immense and evolve over time. In many respects, especially environmentally, the demands we make on our building elements are becoming greater and more sophisticated. The following list is no more than introductory for functions, qualities and materials: Control functions: load-bearing; daylight/view/privacy; wind and weather-resistance; damp resistance; thermal insulation; acoustic insulation; vapour control/permeability; fire resistance; appearance; durability/maintenance requirements. (Foundations covered in chapter 3 pp117, 8) Elements and materials: 1. External walls: natural stone; brick; concrete; concrete block; rammed earth; cob; strawbale; hempcrete; solid timber. Cavity walling: clear, partial-, fully insulated. Framed walling: steel, timber, infilled as above or insulated. Cladding: continuous – render, weatherboarding, tiling, slating etc.; panellised: glass, metals, fibre-cement sheets, etc.

DOI: 10.4324/9781003357995-5

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2. Partitions: masonry (stone, brick, block); framed (timber, steel); boarded (plasterboard, timber etc.); insulated acoustically or thermally; load bearing or load imposing. 3. Party walls: solid masonry; cavity masonry; double framed; acoustic insulated. 4. Boundaries and garden walls: solid or cavity masonry (copings, piers); fences (panelled, railed, wired, meshed); hedges. 5. Ground floors: Suspended: timber joisted; pre-cast concrete (pcc) beam and block; in-situ RC: insulation above/ between/below; cross-­ventilation below. Ground-­bearing concrete/limecrete:sub-base; damp proof membrane (dpm); insulation; vapour control layer (vcl); screed-finished slab (reinforced; underfloor heated); sub-base; dpm; slab; insulation; vcl; screed (reinforced; underfloor heated) or floating floor boarding. 6. Intermediate/party floors: timber or steel or hybrid joisted; pcc planked; in-situ RC; acoustic insulation above (floating) or below; underfloor heating above. 7. Ceilings: plasterboard (and skim/direct decorated) almost universal for flat/pitched ceilings; double or higher grades of fire resistance as required for party floors, structural fire resistance, etc.; wet plaster on mesh for curved details, staircase soffits, etc.; acoustic absorbent materials – ­mineral fibre, etc. – for sound control; panelled ceiling boards and tiles (mineral fibre, etc.) for suspended ceilings for frequent access; other decorative ceiling materials constrained by fire spread limits, for example, timber that can be treated to limit surface spread of flame. 8. Pitched roofs: traditional finish materials: tiles (clay and concrete); slates (natural and reconstituted); shingles (cedar, oak, chestnut); thatch (reed and long straw): traditionally for pitches from 22 to 45 degrees; modern tiles and artificial slates designed for pitches as low as 12 degrees: advantages for small buildings in traditional appearance, low cost and vapour permeability.

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Sheet roofing materials: profiled sheets in steel, aluminium, grp and fibre-cement allow lower pitches, faster installation and low cost for large simple buildings; ventilation required.   Traditional metal roofing in lead, copper, zinc, ternecoated stainless* allows even lower pitches and intricate detailing around openings, terraces, services, etc. Ventilation required. 9. Flat roofing: flat roof materials inevitably unvented so either detailed with ventilation below the deck and above the insulation (‘cold roof’) needing typically eaves and abutment vented details for cross-ventilation; or with insulation placed above the deck (‘warm roof’) to avoid risk of condensation and the need for ventilation.   Flat roofing materials include the traditional metals, lead, copper, zinc and tcss* at higher cost, flexible sheet roofing membranes at lower costs such as EPDM, TCP and TPO adhered, ballasted or mechanically fixed; cold applied liquid roofing membranes, and traditional reinforced bitumen sheet roofing and in-situ-laid asphalt roofing. ‘Green roofs’ are increasing steadily in popularity – ­typically consisting of sedum, grass or wildflower planting over a growth layer and root protection above the roof, they increase structural loadings substantially but can lengthen roofing membrane life, improve insulation, moderate run-off and improve biodiversity as well as enhancing appearance.

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Stairs and balustrades Building regulations requirements

Building elements 275

276 Architect’s Pocket Book Stairs for buildings other than dwellings

Lower handrail for small children's use at 600 300

Balustrade at 1100

600

900 1100

1000

900

300

between handrails 2000

Landing

between handrails

Ideally 12 risers. Max. 16 risers 1000

between walls 1200

1200

900 1100

Risers should have contrasting nosings

Stair width greater than 2m should be divided

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Ramp gradients %

Slope

Application

5%

1:20

Maximum uphill gradient preferred by cyclists Maximum outdoor slope for pedestrians

6.5%

1:15.4

Maximum downhill gradient preferred by cyclists

5.0%

1:20

Maximum wheelchair ramp for a maximum length of 10 m and rise of 500 mm

6.7%

1:15

Maximum wheelchair ramp for a maximum length of 5 m and rise of 333 mm

8.3%

1:12

Maximum wheelchair ramp for a maximum length of 2 m and rise of 166 mm

8.5%

1:11.8

Maximum indoor slope for pedestrians

10%

1:10

Maximum ramp for lorry loading bays and most car parking garages

12%

1:8.3

Any road steeper than this will be impassable in snow without snow tyres or chains Maximum for dropped pavement kerbs of less than 1 m long

15%

1:6.7

Absolute maximum for multi-storey car parks

Fireplaces Building regulation requirements fireplace recesses

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Constructional hearths

Superimposed hearths

Building elements 279

Chimneys and flues Building regulations requirements

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Flues for wood/biomass burning appliances as for solid fuel; particular care is needed to allow for liners installed to cope with tars draining down flues; insulated flues tend to perform better with less condensate; existing traditional masonry chimneys are prone to tar leakage and staining. The use of thermal stores in conjunction with biomass can efficiently minimise these problems by allowing intermittent hot burns.

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Doors Standard doors are manufactured in both metric and imperial sizes due to continuing demand by the building trade. There is also a need for replacement doors in older properties and other sizes are produced for this reason. Unless a large quantity of doors is ordered, standard sized doors are still significantly cheaper than specials. Because of the need to accommodate wheelchair users, wider doors are now more in demand. An 800 mm clear opening is considered the absolute minimum for a wheelchair user. Sixty mm should be deducted from the actual door width to arrive at the clear opening size. This dimension takes into account the thickness of the door and hinges standing open at one side and the rebate or stop on the other side. The majority of standard doors are made as ‘flush’ with plywood or hardboard facings, timber lippings and expanded cardboard cores, or for firedoors, solid chipboard cores. Flush doors include imitation panel doors produced by pressing hardboard facings to the outline and profiles of panel doors. Traditionally made panelled and boarded, framed, ledged and braced doors are made both to standard sizes and to order.

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Typical sizes of single leaf standard doors (metric) 926 × 2040 Exterior Solid panelled Glazed panelled Flush Steel faced Framed and ledged Ledged and braced Interior Solid panelled Glazed panelled Flush Moulded panelled Fire ½ hour 1 hour Structural openings

826 × 807 × 2040 2000

*

726 × 2040

626 × 2040

526 × 2040

* * * * * *

44 44 44 44 44 36 * * * *

* * *

*

*

* *

*

* *

*

1010

910

810

710

610

* *

Thickness (mm)

* *

35 40 40 35 and 40 44 54

Typical sizes of single leaf standard doors (imperial)

Exterior Solid panelled Glazed panelled Flush Steel faced Framed and ledged Ledged and braced Interior Solid panelled Glazed panelled Flush Moulded panelled Fire ½ hour 1 hour

838 × 1981 2′9″ × 6′6″

813 × 2032 2′8″ × 6′8″

* * * * * *

* * *

762 × 1981 2′6″ × 6′6″

686 × 1981 2′3″ × 6′6″

610 × 1981 2′0″ × 6′6″

Thickness (mm)

*

*

* *

* * * * * *

* *

* *

44 54 44 44 44 36

* * * *

* * *

* * * *

* * * *

* * * *

35 & 40 35 & 40 35 & 40 35 & 40

* *

* *

* *

* *

*

44 54

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Other types of doors Fire doors Fire doors are available in most standard sizes in flush doors, and some are also available in internal moulded panelled doors. Half-hour and one-hour fire doors are only rated FD 30(S) and FD 60(S) when used with appropriate door frames that are fitted with intumescent strips (combined with smoke seal). The intumescent strips and smoke seals may also be fitted to the top and long edges of the fire door. Existing panelled doors, particularly in listed buildings, can be upgraded to give 30 and 60 minutes fire protection, using intumescent papers and paints. Source: Envirograf www.envirograf.com French doors Two-leaf glazed doors, opening in or out, are manufactured in hardwood and softwood in the following typical sizes: Metric: 1106 wide × 1994 mm high; 1200, 1500 and 1800 wide × 2100 mm high Imperial: 1168 wide × 1981 mm high (3′10″ × 6′6″) and 914 wide × 1981 mm high (3′0″ × 6′60″). Purpose-made joinery can accommodate different glazing thicknesses and designs. Insulated external doors Insulated and draught-sealed external doors and frames are available finished in aluminium, steel, grp and timber, with multipoint locking mechanisms for security and effective weather resistance. Sliding and sliding folding glazed doors These are available in hardwood, softwood, softwood with external aluminium cladding, uPVC and aluminium in hardwood frames in the following metric nominal opening sizes typically:

284 Architect’s Pocket Book 2 leaf: 3 leaf: 4 leaf:

1200, 1500, 1800, 2100, 2400 wide × 2100 mm high 2400 to 4000 wide in 200 mm increments × 2100 mm high 3400 to 5000 wide in 200 mm increments × 2100 mm high

OX and XO OXO OXXO

Opening configurations are often labelled: O = fixed panel and X = sliding panel when viewed from outside. Some manufacturers offer all panels sliding. Some can provide sliding doors meeting at an open corner. Many manufacturers will make bespoke sizes to suit the height and width of openings dependent on the weight of the leaves. Slim aluminium frames down to a 22 mm profile are available in double glazing for doors up to 3500 mm wide. Pocket doors A pocket door is a system of building a counter frame that is then integrated with stud wall construction, either timber or metal. The pocket door counter frame creates an envelope the same width as the finished wall for the door to slide into, thus hiding the door within the wall cavity. They are particularly useful in confined spaces or where creating simple concealed openings between rooms, though the structural opening has to be double the size of the door to accommodate them. Garage doors Garage doors are manufactured in hardwood, softwood, plywood, steel and GRP. Doors can be hinged, or up and over, canopy style or fully retractable; with roller doors in panels or slats vertically or horizontally rolled; all of these can be electrically opened. Insulated and draught-sealed garage doors are available from some manufacturers. The following typical sizes exclude the frame that is recommended to be a minimum of ex 75 mm timber.

Building elements 285

Single

Double

W mm

h Mm

1981 × 1981 1981 × 2134 2134 × 1981 2134 × 2134 2286 × 1981 2286 × 2134 2438 × 1981 2438 × 2134 4267 × 1981 4267 × 2134

(6′60 × 6′6″) (6′60 × 7′0″) (7′00 × 6′6″) (7′0″ × 7′0″) (7′6″ × 6′6″) (7′6″ × 7′0″) (8′0″ × 6′6″) (8′0″ × 7′0″) (14′0″ × 6′6″) (14′0″ × 7′0″)

Other double doors available in widths up to 4878 (16′0″)

Door handing

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Traditional wooden doors definitions and typical sections

Building elements 287

Windows Windows listed below are manufactured in softwood, modified softwood such as Accoya, softwood with aluminium cladding, hardwood, thermally broken aluminium and steel, and in PVC in a wide range of sizes and types. Standard sized windows are less significant on smaller projects and most windows are made to order from standard sections or purpose-made. Very low energy windows to meet Passivhaus standards – whole window U-values < 0.8 W/m2 K – are typically made with triple glazing, laminated frames and sashes including insulation material. Upper floor windows in dwellings require minimum opening sizes to allow egress in the case of fire as set out in Approved Document B Volume 1.

Side and top hung casements This is by far the most common type of standard window in the UK. They are available as single sashes or in twos, threes and fours. There are numerous combinations of fully opening sashes, one or more fixed lights and smaller top hung vents, with or without glazing bars. Sashes can be fitted with reflex hinges, in lieu of conventional hinges, for easier cleaning from inside.

Bay windows Square, splayed at 45º semi-circular and shallow curved bay windows are available using combinations of fixed lights, side and top hung casements and double hung sashes to suit structural opening widths of approximately 1200–3500 mm.

Fixed lights A range of fixed light windows sometimes referred to as direct glazed can be a wide range of shapes and sizes.

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Double hung sashes Modern double hung sashes with spiral balances, some fitted with a tilting mechanism allowing for easier cleaning from the inside. With and without glazing bars. Traditional double hung sashes hung on lead weights in boxes can be made to any size, though double-glazed sashes are restricted by the weight of the glass that can be balanced by the sash weights. Slimline double glazing can reduce the weight of the frame.

H-Windows High-performance windows with complex hinge mechanism allowing partial projection for ventilation and complete reversal for cleaning. Available also as a side hung escape window.

Tilt-and-turn windows These are the most widely available European high-­performance windows, particularly in the very low energy ranges, to Passivhaus standards etc.; they have two opening configurations: bottom hung inwards tilt for relatively secure ventilation, and side hung inwards turn for cleaning or escape.

Energy ratings The BFRC (British Fenestration Rating Council) Scheme is the UK’s national system for rating the energy efficiency of windows and doors and is recognised within the Building Regulations as a method to show compliance for replacement windows installation. The BFRC label clearly indicates the rating of the designated window or door (A++ to E) depending on the energy efficiency

Building elements 289

levels achieved by the manufacturer. A++ is the most energy efficient, E the least efficient. The level of energy efficiency is indicated by one of a range of coloured bars – very similar to the energy efficiency labels found on fridges, freezers, washing machines and other household products. During the rating process, the energy efficiency level is calculated and verified by BFRC, which is totally independent from any manufacturing or installing company. Manufacturers of BFRC-rated product and BFRC Authorised Installers are audited to ensure that their energy-efficient windows and doors are achieving the stated rating. 1. The rating level – A++, B, C, etc… 2. The energy rating – 3kWh/(m²·K) – in this example, the product will lose 3 kilowatt hours per square metre per year. 3. The window U value, for example, 1.4W/(m²·K) 4. The effective heat loss due to air penetration as L For example, 0.01 W/(m²·K) 5. The solar heat gain, for example, g = 0.43 The BFRC Noise Reduction Rating scheme proves the acoustic performance of windows and doors using the ‘rainbow’ rating label. Source: British Fenestration Rating Council www.bfrc.org

Glazing Most windows have rebates suitable for double glazing units (as required under Building Regulations) up to a thickness of 28 mm for high performance, although slim double-glazed units are available with overall thicknesses of 10–12 mm for use specifically in historic buildings. Double-glazed units are available with a choice of plain, obscured, annealed,

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laminated or toughened glass. To meet Building Regulations Part L, double glazing has to include a low-e coating applied to the outer face of the inner pane. Hard coatings are more robust for handling, but soft coatings are more efficient thermally. Inert gas filling, such as argon, krypton or xenon, and the use of non-metallic insulating spacers to the perimeter maximise thermal performance, with triple glazing, the next step to bring whole window U-values down to below 0.8 W/m2 K, as appropriate for Passivhaus standards, for example, 2 + 1 triple glazed units can incorporate blinds to assist with solar control and glare. Leaded lights are windows made up of small panes of glass, either regular or patterned as in stained glass, which are set in lead cames – ‘H’ section glazing bars. Protection The Building Regulations require that all glazing below 800 mm above floor level in windows and below 1500 mm above floor level in doors and sidelights, and sidelights that are within 300 mm of a door, should be fitted with safety glass. Small panes should have a maximum width of 250 mm and an area not exceeding 0.5 m2 and should be glazed with glass a minimum 6 mm thick. Building Regulations Approved ­Document K. Weather stripping Weather stripping should always be provided as standard to all opening lights to minimise air leakage and should be kerf-fixed rather than adhered. Finishes Timber windows are normally supplied primed for painting or with a base coat for staining. Options may include complete painting or staining with guarantees available up to ten years.

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Ventilation MVHR Most windows are now fitted with ventilators in the headframe providing either 4000 mm2 in the narrower windows or 8000 mm2 controllable secure ventilation to suit current Building Regulations in the wider windows. Low energy buildings provided with MVHR systems are not required to have window ventilators. Fittings Fasteners, peg stays, hinges, etc. all supplied with the windows in aluminium, chrome, stainless steel, gold spray, lacquered brass, brown, white or other colour finishes, at extra cost. Swept heads Elliptical curves for the tops of panes available factory fitted or supplied loose. Curved shapes not available in aluminium-clad timber windows from all suppliers. Fire Escape Windows…need to provide an unobstructed openable area that is at least 0.33 m² with no dimension being less than 450 mm. A clear unobstructed opening 450 mm wide by 750 mm high achieves this.

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Traditional wooden windows, definitions and typical sections

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Protection for glazing indoors and windows based on Building Regulations Approved Document K

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Pitched rooflights Centre pivot rooflights Designed for roof pitches between 15º and 90º, or 10º–20º. Lacquered pine or polyurethane-coated frames, double or triple glazed with a choice of glass: clear, obscured, toughened, laminated and low-e coated. Glass cavities are gas filled with optional coatings to achieve U-values of 1.3 down to 0.8 if triple glazed W/m2K: Standard sizes, overall frame w × h mm 422 × 978 550 × 778 550 × 978 550 × 1178

660 × 978 660 × 1178

780 × 978 780 × 1178 780 × 1398 780 × 1600

942 × 978 942 × 1178 942 × 1398 940 × 1600

1340 × 978 1140 × 1178 1140 × 1398 1140 × 1600

1340 × 1398 1340 × 1398

Finishes: externally – grey aluminium as standard, other finishes are available including titanium zinc and black (for conservation rooflights). internally – lacquered or white painted timber frames; polyurethane frames finished white. Fittings: Control bar at head operates window and ventilation flap; friction hinges; barrel bolt for locking in two positions; security bolts. Flashings:

Available to suit most roofing materials. If required they can enable windows to be fitted side-by-side or one-above-the-other and in groups. An insulation collar and vapour barrier maximise energy efficiency

Accessories: External awning blinds (essential to control heat gain from south-facing rooflights); roller shutters. Internal insect screens; interior linings. Roller, black-out, pleated or venetian blinds.

Building elements 295

Cord, rod and electronic controls for operating sashes, blinds, etc. Break-glass points. Smoke ventilation system to automatically open window in the event of fire. Pre-installed electric system to operate high level skylights via an infra-red remote control. Top hung rooflights Designed for roof pitches where a pivoted window might interfere with headroom. Suitable for pitches between 15º and 55º (and up to 75º with special springs). Can be rotated 180º for cleaning. Some versions are available for an escape/access door. Sizes similar to pivoted windows. Flat roof lights Designed for flat roof pitches between 0o and 15o with flat, curved or domed glazing or polycarbonate and options for venting. Additional fixed light windows These may be fitted directly above or below a roof window, within the same plane, to extend the view and increase daylight. Balcony system A top hung roof window opens out horizontally and is combined with a bottom hung lower sash fixed in the same plane. The lower sash opens out to a vertical position and railings automatically unfold to close the sides and create a small balcony. Roof terrace system This system combines a top hung roof window with a vertical side hung opening out sash fixed below with no intermediate transom, allowing access to a balcony or terrace.

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Additional vertical windows Where floor level is below the eaves and more light and view is required, bottom hung or tilt-and-turn windows may be fixed in the vertical plane directly below roof windows fixed in the sloping roof above. Conservation area roof windows Centre pivot or top hung rooflights windows with a central vertical glazing bar, recessed installation and black external finish that may be acceptable to Listed Building Officers for Listed Buildings and Conservation Areas. Sizes:

550 × 980, 550 × 1180 660 × 1180, 780 × 1180 780 × 1400, 1340 × 980, 1140 × 1600

Source: Velux Company Ltd www.velux.co.uk.

Flat rooflights Individual rooflights are typically square, rectangular or round on plan and come as flat glass sheets, domes or pyramids. Plastic rooflights to be suitable for any space except a protected stairway must be rated TP(a) rigid. Typical sizes nominal clear roof openings Square:

600, 900, 1200, 1500, 1800 mm.

Rectangular: 600 × 900, 600 × 1200, 900 × 1200, 1200 × 1500, 1200 × 1800 mm, 1200 × 2000. Round: 600, 750, 900, 1050, 1200, 1350, 1500, 1800 mm Ø.

Materials Toughened/ laminated glass: Polycarbonate:

double or triple glazed fire rating: Class 0, can be walked on. Clear, opal and tinted. Almost unbreakable, good light transmission, single, double or triple skins.

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Fire rating: TP(a) Class 1 Average U-values: single skin 5.3 W/m2K double skin 2.8 W/m2K triple skin 1.9 W/m2K PVC: Clear, opal and tinted. Cheaper than polycarbonate but will discolour in time. Single and double skins Fire rating:  TP(a) Class 1 U-values:   single skin 5.05 W/m2K double skin 3.04 W/m2K Kerbs Kerbs are generally supplied with rooflights, but they may also be fitted directly to builder’s timber or concrete curbs. Curbs typically have 30º sloping sides, are made of aluminium or GRP and stand up 150–300 mm above roof deck. They can also be supplied as a composite insulated panel with vertical sides. They may be uninsulated, insulated or topped with various forms of ventilators, normally fixed or adjustable louvres, hand or electrically operated. Access hatch: Hinged rooflight, manually or electrically operated, typically 900 mm sq. Smoke vent: Hinged rooflight linked by electron magnets to smoke/heat detecting systems. Optional extras: Bird and insect mesh for vents in kerbs. Burglar bars – hinged grille fixed to kerb or in-situ upstand. Sources: w ww.coxdome.co.uk www.duplus.co.uk www.glazingvision.co.uk www.sunsquare.co.uk Patent glazing Systems of puttyless glazing normally used for roofs but can also be used for curtain walling. The glazing bars, usually aluminium, can be several metres long and are normally spaced

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at 600 mm centres. The bars have concealed channels to drain the moisture out at the eaves of the roof or the bottom of the wall glazing. Double glazed with sealed units fitted with neoprene gaskets, or single glazed over external spaces. The bars are also available as thermally broken and with opening lights. They can be self-supporting or on timber rafters. Solar control is more difficult to achieve with these systems except by use of solar control glass, so orientation should be considered carefully. Sunpipes

A mirror-coated tube that transfers daylight from a ­diamondfaceted dome, or flush square rooflight, at roof level to an internal space. It can suit any roof profile and bend to suit the geometry. Diameters range from 230 to 530 mm and can be combined with solar-powered ventilation. Source: www.monodraught.com

Building elements 299

Security fittings and ironmongery Security against intruders is becoming ever more sophisticated with new electronic technology. However, it is important to ensure the physical protection of buildings and particularly to have a secure perimeter. Secured by Design focuses on crime prevention at the design, layout and construction stages of homes and commercial premises and promotes the use of security standards for a wide range of applications and products. Building Regulations Part Q covers security requirements in buildings, including references to PAS 24 and Secured by Design.

External doors External doors must be sufficiently strong and properly installed to resist shoulder charges and kicking. Doorframes should have minimum 18 mm rebates and be firmly fixed to openings at 600 mm centres. Doors should have a minimum thickness of 44 mm with stiles at least 119 mm wide to accommodate locks. Panels should not be less than 9 mm thick. Flush doors should be of solid core construction. Meeting styles of double doors should be rebated.

Door ironmongery Front doors should be fitted with a high security cylinder lock for use when the building is occupied, with an additional five-or seven-lever mortice deadlock to BS 3621 BS EN 12209: 2003. Back and side doors should be fitted with a similar deadlock with two security bolts at the top and bottom. Deadlocks should have boxed striking plates to prevent jemmy attack and hardened steel rollers to resist hacksawing. High-performance entrance doors have multipoint lever-operated locking systems that enhance security as well as energy saving. Doors should be hung on three (1½ pairs) metal broad butt hinges. Outward

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opening doors should have hinge bolts to prevent doors being levered open on the hinge side. Position letter plates at least 400 mm from any lock. Fit door viewers and door chains to any door likely to be opened to strangers. Chains should be fixed with 30 mm long screws to prevent being forced open. Entrance doorways should be lit so that callers can be seen at night. Burglars are wary of breaking glass, so glass doors are not necessarily vulnerable providing the glass is fixed from the inside. However, sliding glass doors are particularly vulnerable. The main mortice lock bolt should be supplemented by a pair of key-operated locking bolts fixed at the top and bottom. Anti-lift devices should be fitted in the gap between the door panel and frame to prevent the outer door being lifted off the runners.

Windows Rear windows are most at risk, as are windows accessible from balconies or flat roofs. Sliding windows should be designed so that it is impossible to remove sashes or glass from the outside. External hinge pins and pivots should be secured by burring over. Window and door frames require sufficient stiffness to prevent distortion under attack that can ‘release’ glazing units and sashes without breakage; for pvc frames, this can involve steel reinforcement. Avoid rooflights that have domes fixed with clips that can be broken from outside. Where escape from fire is not required, fix metal bars or grilles below rooflights.

Window ironmongery All ground floor, basement and any upper floor vulnerable windows should be fitted with two security bolts to each casement sash and to the meeting rails of double hung sashes. Upper floor sashes should have at least one security bolt. For greater safety, choose locks with a differ key rather than with a common key, which experienced intruders will own. Many window handles include locks as standard.

Building elements 301

Other physical devices Collapsible grilles, sliding or rolling shutters and, where appropriate, blast and bullet-proof screens and ram stop bollards. Safes for domestic use can be as small as ‘two brick’ wall safes or floor safes let into floors. Larger floor safes weigh from 370 kg to 2300 kg and must be anchored to floors. Locks may be key, combination or electronic. Electronic devices include the following: • Access control – voice/video, keypad, card reading entry, phone systems • Intruder detection –  intruder alarms, CCTV surveillance, security lighting • Fire/gas protection –  smoke and heat detection, fire alarms, ‘break glass’ switches, automatic linking to fire stations. Carbon monoxide and dioxide alarms. Alarms systems can be integrated with other building electronics installations and can be remotely monitored by owners or their agents. Sources:  Secured by Design https://www.securedbydesign. com/guidance/design-guides “Homes 2019” Approved Document Q: Security – Dwellings – (applies to new dwellings only) Banham Security www.banham.co.uk

6 Materials and components Building materials are the architect’s palette, critical to success in every respect from the functional and economic to the psychological and aesthetic. Their selection has increasingly complex environmental and socio-economic implications.

Concrete The second most widely used substance in the world after water, concrete ranges from the most basic below ground uses in building to some of the most sophisticated and costly finishes that fashion dictates. The production of cement, its ‘active ingredient,’ is estimated to generate around 5% of global CO2 emissions, though energy efficiency in manufacture is improving. Increasing inclusion of cement substitutes in concrete and substitution of lime for cement both serve to reduce environmental damage though the greatest potential is in more efficient design and fabrication of structural concrete stimulated by environmental and cost pressures. Aerated concrete: A lightweight concrete with no coarse aggregates, made of cement, lime, sand and chemical admixtures that cause bubbles to make a cellular consistency. It has low strength but good insulation properties. It is easily cut and nailable. There are many grades, some unsuitable below ground. Water absorption will impair its thermal performance. Lightweight aggregate concrete: lightweight concretes produced using partly or wholly lightweight aggregates such as vermiculite, perlite or LECA (lightweight expanded clay aggregate). Can be useful thermally, for fire protection and where flotation is temporarily required during construction. DOI: 10.4324/9781003357995- 6

Materials and components 303

Bush hammering: Tooling concrete or stone with a compressed air hammer to remove 1 to 6 mm of the outer skin to reveal a surface texture that improves its appearance. Granolithic finish: A thin topping of cement, granite chippings and sand laid over a concrete slab, preferably as a monolithic screed to provide a good wearing surface. Can be made non-slip by sprinkling carborundum powder over the surface before final trowelling. Glass-reinforced concrete (GRC): Precast concrete, reinforced with glass fibre to make thin panels with improved strength and impact resistance. Polymer-impregnated concrete: Concrete made with a polymer to improve the strength by filling all the voids normally left in conventional concrete. Water absorption is thus reduced and the concrete has greater dimensional stability. Refractory concrete: Concrete made with high alumina cement and refractory aggregate, such as broken firebrick, to withstand very high temperatures. Exposed aggregate concrete: Concrete made with aggregate selected for its appearance, texture, etc. that is exposed by washing the concrete surface after the initial set so as to remove fines and laitance; used for decorative finishes to concrete components and for non-slip decorative paving. Limecrete: Concrete made with hydraulic lime in lieu of Portland cement for reduced CO2 and for permeability – but at a much higher cost. Typical use for new permeable floor slabs with underfloor heating over foamed glass permeable insulation granules in historic buildings. Hempcrete: Medium weight concrete made by combining lime or cement, sand and hemp shiv as a non-structural fill with reduced CO2 and environmental impact. Rammed earth: medium weight mass construction using low organic content local soils rammed into wall shutters to build structural walls, can be left exposed for natural decorative

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effects internally; requires weather protection externally; very low CO2 when dug on site but high labour costs. Cob and clunch: traditional walling of locally sourced earth/ straw/manure (cob) and earth/chalk (clunch); traditionally built very slowly without shuttering in short layers; requires weather protection both during and after construction; variable medium density and very low CO2 but especially labour-intensive.

Brickwork and blockwork Brick manufacture Clay is extracted from the earth, with brick properties changing depending on the geographical location of the clay source as well as the depth of the clay within the quarry itself. Depending on the required properties of the finished material, it is sometimes necessary to mix clays from different locations and depths. The clay is then transformed into a plastic mouldable material by grinding and mixing with water. If there are large lumps of clay, rock crushing may be required to reduce the size of the clay rock particles. A brick’s shape is formed by one of two processes: Extrusion: a long clay column or slug shape is created and then cut into individual brick units. The bricks made through this method are typically perforated and may be solid but without frogs (a frog is an indentation in one or more of the bed surfaces of the brick). Soft mud moulding: bricks are formed by mould boxes; this process can either be done by hand by craftsmen who produce one brick at a time, or by automation where large numbers of bricks can be produced at one time. Bricks using this method are typically made with frogs although some can be solid. Bricks must then be dried to reduce as much moisture as possible to prevent bursting when they are fired. Dryers are

Materials and components 305

typically kept at temperatures of 80–120°Celsius with high humidity to keep the outside of the brick as moist as possible, while allowing the brick to dry from the inside out. Drying can take between 18 and 40 hours for standard shapes whilst specials can take longer. Green bricks, or unfired bricks, are not weather proof and can be used for internal walls or where they will be unaffected by the elements. Firing temperatures differ between clay types. During the firing process, clay particles and impurities are fused together producing a hard weatherproof material. Bricks shrink during drying and firing, and this has to be taken into account when deciding on the mould size. Temperatures vary depending on the type of clay being used but typically range from 900° to 1200°Celsius. Due to the very high temperatures involved, the firing process takes place over three stages: Pre-heating: this stage ensures the bricks are completely dry Firing: fuel is then used to increase and maintain the temperature Cooling: air is drawn into the kiln to reduce temperatures to enable the bricks to be handled for sorting and packing. Cellular clay blocks: produced by extrusion for thin multicellular form, widely used in Europe for medium weight partitions and non-structural infill to external walls; an insulating alternative to aerated concrete blocks. Unfired clay bricks: Compacted and dried but not fired, they have low embodied energy and CO2 but low strength and no weather resistance so for non-­structural internal use only. Source: Brick Development Association www.brick.org.uk

Brick sizes The work (actual) size of the standard brick is 215 × 102.5 × 65 mm

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For the coordinating size, which includes the width of one mortar joint, add 10 mm, i.e. 225 × 112.5 × 75 mm Metric modular sizes: 190 × 90 × 65 mm Other less available brick sizes: 215 × 102.5 × 50 mm 215 × 102.5 × 73 mm 215 × 102.5 × 80 mm 290 × 102.5 × 50 and 65 mm 327 × 102.5 × 50 and 65 mm 450 × 102.5 × 50 and 65 mm 520 × 102.5 × 37

Weight of bricks kg/m3 Blue Engineering Sand cement Fire brick London stock Sand lime Flettons Red facings

2405 2165 2085 1890 1845 1845 1795 1765

Compressive strengths and percentage water absorption Brick

N/mm2

Water absorption % by mass

Engineering Class A Engineering Class B Flettons London stocks Hand moulded facings

.70 .50 14–25 3–18 7–60

4.5 7.0 15–25 20–40 10–30

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Frost resistance and soluble salt content of bricks Bricks are categorised according to the degree of frost resistance they exhibit, with a further categorisation of their soluble salt content. Soluble salt content is categorised as L – low, or N – normal. Soluble salt content may have some effect on the incidence of efflorescence on brickwork, although soluble salts within the mortar and in groundwater may also affect its appearance. The frost rating is combined with the salt content rating to give six possible categories for all clay bricks: FL and FN, ML and MN or OL and ON. For most landscaping works, only bricks from class FL or FN are suitable, although some ML/MN bricks may be suitable for brickwork more than 150 mm below ground level. Designation

Frost resistance

Soluble salt content

FL

Frost-resistant

Low salt content

FN

Frost-resistant

Normal salt content

Suitable for all building work, including situations where they may be repeatedly saturated, such as retaining walls or below ground level ML

Moderate frost resistance

Low salt content

MN

Moderate frost resistance

Normal salt content

Fairly durable when used in non-saturated conditions, i.e. between the DPC and the eaves of a house OL

Not frost-resistant

Low salt content

ON

Not frost-resistant

Normal salt content

Only suitable for internal use; should not be used in landscaping projects

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Brickwork bonds

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Mortar mixes for brickwork and blockwork Grade designation

Cement: lime: sand

Masonry cement: sand

Cement: sand with plasticiser

Compressive strengths N/mm2 preliminary site

I II III IV

1:¼:3 1:½:4 to 4½ 1:1:5 to 6 1:2:8 to 9

— 1:2½ to 3½ 1:4 to 5 1:5½ to 6½

— 1:3 to 4 1:5 to 6 1:7 to 8

16.0  6.5  3.6  1.5

11.0  4.5  2.5  1.0

Notes: 1 Mortar designation I is strongest; IV is weakest. 2 The weaker the mix; the more it can accommodate movement. 3 Where sand volume varies, use the larger quantity for well-graded sands and the smaller quantity for coarse or uniformly fine sands. 4 Grades I and II for high strength bricks and blocks in walls subject to high loading or walls subject to high exposure such as retaining walls, below DPC, parapets, copings and free-standing walls. 5 Grades III and IV for walls between DPC and eaves not subject to severe exposure.

Pure lime mortars, using lime putty or hydraulic lime without cement, are widely used for historic building work and for new work where expansion joints are to be avoided; for weaker bricks and stones, lime mortars offer a longer life and better weather resistance.

Joints Flush Maximum bearing area Useful for coarse-textured bricks Evens out run-off and absorption; best for long life and weather resistance Bucket handle More visual joint emphasis than flush and almost as strong and weather-resistant Struck or weathered Gives a shadow line to joint. If correctly made is strong and weather-resistant. Recessed This can allow rain to penetrate and should be confined to frost-resistant bricks and sheltered situations.

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Special bricks

Materials and components

Source: Ibstock Brick Ltd www.ibstockbrick.co.uk

311

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Concrete Blocks Sizes The standard block face dimensions are: 440 × 215 mm and 440 × 140 mm, with thicknesses of 75, 90, 100, 140, 150, 190, 200 and 215 mm. Health and safety restrictions on site manual lifting limit block weights to no more than 20 kg, which restricts the use of dense solid blocks in standard formats to 100 mm thickness, or their substitution by lightweight aggregate or hollow blocks; hollow dense blocks up to 190 mm thick are within the 20 kg limit.

Typical foundation block sizes are: 440 × 215 mm and 440 × 140 mm, with thicknesses of 224, 275, 305 and 355 mm. Unless these are mechanically handled, lightweight blocks are used. Compressive strength: Blocks range from 2.8 to 7.0 N/mm2 depending on composition. 4.0 N/mm2 is average. There is a wide range of medium and lightweight blocks available from most block manufacturers; the most effective

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thermal insulating blocks are made from aerated concrete and can achieve conductivities as low as 0.11, which can make a significant contribution to wall insulation, particularly effective as simple thermal break courses level with ground floor insulation in dense block walling. Several aerated concrete block makers have ranges of thin joint ‘glued’ masonry that speeds construction, improves accuracy and thermal performance. The airflow resistance of concrete blocks varies according to their manufacture: aggregate blocks with open-textured faces and low fines content can be seriously leaky and cause significant heat loss, particularly if finished with dry lining rather than wet plaster. For environmental reasons, unfired clay blocks and bricks alongside hemp–lime and similar materials are available for less structurally demanding conditions.

Cavity wall ties Spacing of wall ties About 65–90 mm leaf thickness = 450 horizontally/450 mm vertically. Over 90 mm leaf thickness = 900 horizontally/450 mm vertically. For wider cavities, spacing may decrease and are subject to approval by Building Control.

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Cavity wall ties are made in stainless steel (wire diameters from 2.5 to 4.5 mm) or reinforced plastic for reduced thermal bridging, which can be equivalent to 50 mm of cavity insulation. Lengths are from 150 to 300 mm depending on wall thickness and cavity width. Extra-long ties are available for insulated cavities up to 250 mm wide. Most ties can be fitted with clips to retain partial cavity insulation boards. Outer leaf moisture drips from central twists and kinks. See websites such as www.ancon.co.uk for a selection of wall ties for different applications.

Brick-paving patterns

Materials and components

315

Paving slabs and block paviours Concrete paving slabs: sizes up to 600 × 600, and thicknesses from 38 to 50 mm. Setts/block paviours: mixed sizes in concrete, brick or stone 200 × 100, 100 × 100 × 40–80mm Stone paving slabs: mixed sizes from 300 × 300–600 × 900, thickness 15–40 mm Permeable paving is specified to allow water to drain through and be collected as part of Sustainable Urban Drainage systems. Geotextile membranes should be used below paving to prevent weed growth and minimise the use of chemical weed killers. Slab pavings are typically bedded on mortar dabs over hardcore for pedestrian use and fully bedded on a concrete sub-base for vehicular use; joints are typically pointed in mortar or dry-brushed. Block paviours are typically laid on a full sand bed and vibrated with sand-filled joints. Paving slabs can also be supported on adjustable polypropylene pedestals that vary in height and can cope with sloping substrates.

Clayware: definitions Earthenware Pottery made from brick earth; softer than stoneware. Exposed surfaces are often glazed. Firebrick Bricks made from any clay that is difficult to fuse and generally has a high quartz content. Used for fire backs and boiler liners for temperatures up to 1600°C. Stoneware Highly vitrified clayware used for sanitary fittings and drainpipes. Vitreous china A strong high-grade ceramic ware made from white clays and finely ground minerals. All exposed surfaces are coated with an impervious non-crazing vitreous glaze. Used for sanitary ware, it is easy to clean but brittle compared with glazed stoneware.

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Vitrified clayware Clay that is hard-burnt to about 1100°C and therefore vitrified throughout. It has low water absorption, and can be used unglazed for floor tiles, drainpipes, etc. Can be fair cut with an angle grinder.

Stonework Building stone comes from three rock types: • Igneous rocks formed from cooled molten rock, e.g. granite. • Metamorphic rocks formed from the re-crystallisation of previous rocks after heat and pressure, e.g. slate and marble. • Sedimentary rocks formed from ancient sediments deposited on sea or river beds and then compacted or naturally cemented, e.g. limestone or sandstone.

Typical building stones Stone

County

Colour

Compressive Dry weight strength (kg/m3) (kN/m2)

Granites Cornish Peterhead Rubislaw

Cornwall Grampian Grampian

Silvery grey Bright red Bluish-grey

2610 2803 2500

113 685 129 558 138 352

Sandstones Bramley Fell Darley Dale Forest of Dean Kerridge Runcorn red

W Yorks. Derbys. Glos. Derbys. Cheshire

Grey to buff Light grey Grey to blue Buff Red and mottled

2178 2322 2435 2450 2082

42 900 55 448 67 522 62 205 27 242

Limestones Ancaster Bath Clipsham Mansfield Portland

Lincs. Wilts/Somerset Leics. Notts. Dorset

Cream to brown It. brown to cream Pale cream to buff Creamy yellow It. brown to white

2515 2082 2322 2242 2210

23 380 24 024 29 172 49 550 30 780

Stonework should be laid according to its natural bed for durability. Stone may be required from different quarries for walls, sills and copings.

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Mortar mixes for stonework Typical mix

Application

Cement: hydrated lime: sand

1:3:12

Putty/hydraulic lime:sand Cement:hydrated lime:sand Cement:hydrated lime:sand

2:5 1:2:9 1:1:6

Dense stones (granite, etc.), not limestones Most building stones Exposed details, not limestones Most sandstones

Joints

Thickness (mm)

Internal marble cladding External cladding Slate cladding Large slabs Polished granites Fine ashlar Rubble walls

1.5 2–3 3 4.5 4.5 6 maximum 12–18

Sources: Mc Kay’s Building Construction (published by Routledge).

Damp-Proof Courses DPCs provide an impermeable barrier to the passage of moisture from below, from above or horizontally. They can be flexible, semi-rigid or rigid. Rigid DPCs are only suitable for rising damp. Soft metal DPCs are expensive but safest for intricate situations. Cavity trays are needed above elements that bridge cavities to direct water to outside and at ground floor level where radon is present. DPCs should be bedded both sides in mortar. Seal DPCs to floor membranes. Upper and vertical DPCs should always lap over lower or horizontal ones. DPCs must not project into cavities where they may collect mortar and bridge the cavity.

318 Architect’s Pocket Book Minimum Joint thickness mm

Type

Material

Flexible polymer based

Polyethylene 0.46 lap 100 mm min. and sealed

Bitumen polymer Flexible bitumen based

Bitumen/ 3.8 hessian base

Bitumen/ hessian base/lead Semi-rigid Mastic asphalt Lead

Rigid

1.5

4.4

100 mm. min. lap H at base of walls, Hessian may decay, but OK if bitumen not disturbed. and sealed under copings, sills; CT, V at jambs If cold, warm DPC before use, may extrude under high loads or temperatures 100 mm min. lap H at base of walls, Lead lamination gives extra tensile strength and sealed under copings, sills; CT, V at jambs None

H under copings

1.8

100 mm min., welted against damp from above 100 mm min., welted against damp from above

H under copings, chimney stacks

0.25

Slate

Two courses 4.0 Two courses 150

Remarks

H at base of walls, Appropriates lateral; under sills, vertical movement; tough, easy to seal, expensive, can be jambs punctured H at base of walls, stepped; CT; V at jambs

12.0

Copper

Brick to BS EN 771-1

100 mm min. lap and sealed

Application

H under copings, chimney stacks

Laid to break joint H at base of free-standing and retaining walls Laid to break joint H at base of free-standing and retaining walls

Grit should be added for key, liable to expand Corrodes in contact with mortar, protect by coating both sides with bitumen Good against corrosion, difficult to work, may stain masonry green Very durable, bed in 1:3 sand cement Good for free-standing walls

H = horizontal; V = vertical; CT = cavity tray.

Damp-Proof Membranes (DPMs) DPMs are sheet or liquid membranes designed to resist damp caused by capillary action. They do not have to perform as well as tanking membranes, which must resist water pressure. DPMs may be positioned under site slabs providing the hardcore is smoothed with 25 mm minimum rolled sand or preferably 25 mm smooth blinding concrete. This position is more vulnerable to damage than placing them over smooth finished site slabs. In this position, the membrane prevents bonding between slab and screed, so a thick screed is needed, ideally at least 63 mm. DPMs must be carried up to lap or join DPCs in walls. Brush-­ applied membranes are better than sheets in this respect. Care

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must be taken not to penetrate membranes when laying. Any pipe ducts must be in position before screeds are poured, as any subsequent chasing could well damage the DPM. Type

Description

Low-density polyethylene film (LDPE)

Min 0.3 mm thick. Cheapest DPM, protects against methane and radon gas. No good against any water pressure. Joints must be rigorously taped. Easy to penetrate on site. Often made of recycled material

Cold-applied bitumen solutions; coal tar; pitch/rubber or bitumen rubber emulsions

Ideally three coats. Must be carefully applied to avoid thin patches and pinholes

LDPE plus bitumen sheet

Not as easily displaced as LPDE film and easier to overlap. Small perforations less likely, as will ‘self heal’

High-density polyethylene (HDPE) with bitumen to both faces

High-performance PE core is coated both sides with bitumen, with upper surface bonded to this PE film. Underside has a film that is released before laying

Drained cavity membranes

Below ground walls and floors are lined with studded polyethylene and polypropylene membranes allowing water to be controlled and diverted away from the structure draining via channels to external drainage

Self-adhesive sheet membranes

HDPE used with tanking primers for improved adhesion are resistant to puncture and tearing

Cementitious coatings

These can be used externally and internally, and in conjunction with drained cavity membranes but lack flexibility.

Ground gas protection Ground gas protection against radon, methane, carbon dioxide and hydrocarbons is provided by sheet membranes and cavity barriers as required under Building Regulations. Site radon levels need to be checked prior to detailed dpm design; simple checks are available on-line. Checks will indicate one of three radon levels and protection required: none; basic protection; full protection. Basic protection can be provided simply by connecting carefully sealed dpms to perimeter DPCs via cavity trays. Full protection requires sub-floor venting with the potential of passive stack or fan-assisted ventilation. For ground bearing floors, the vent duct is connected to a central vent sump – effective to a radius of approx 15 m or for an area of 250 square metres. Sources: Visqueen Building Products www.visqueen.com Delta membranes www.deltamembranes.com

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Plaster and render External rendering Rendering mortars are essentially the same as those for laying masonry, but should be made with clean, sharp, washed, plastering sand. Where possible, use the same mix for undercoats as for finishing coats, otherwise the undercoat should be stronger than the finishing coat. Strong backgrounds, such as concrete or engineering brick, may need an initial keying coat or spatterdash such as 1:1½ or 1:3 cement: sand thrown on and not trowelled. For severe exposures, two undercoats are preferable. On metal lathing, two undercoats are invariably needed; it is particularly important to reduce the chances of rendering cracking and increase the possibility of moisture evaporating through it to the exterior; these factors are crucial for the rendering of existing buildings that may have poor DPCs or none. Since strong cement mixes increase shrinkage cracking and prevent evaporation, they should be avoided. Traditional buildings should be rendered using hydraulic or putty lime without cement; render for modern buildings should preferably be carried out with weak cement: hydrated lime: sand mixes for improved flexibility, or with proprietary render mixes. Undercoats can have polypropylene or glass fibres included in the mix to minimise cracking. Proprietary pre-mixed, pigmented renders are available in a wide colour range of pastel shades for either two coat or single coat hand or machine application. Colour matched plastic render beads are available, though not as permanent as stainless steel beads.

Materials and components 321

For all render finishes, care needs to be taken to allow for background movement, particularly in relation to openings and narrow area proportions where stresses can cause cracking.

Rendering mixes for different backgrounds and exposures Use

Background

Severe

Moderate

Sheltered

First and subsequent undercoats

Dense, strong Moderately strong, porous Moderately weak, porous Metal lathing

II III III I / II

II III IV I / II

II III IV I / II

Final coats

Dense, strong Moderately strong, porous Moderately weak, porous Metal lathing

III III III III

III IV IV III

III IV IV III

Plaster and render glossary Aggregate Sand particles or crushed stone that forms the bulk of a mortar or render. Binder A component that hardens to bind aggregates together; normally lime and/or Portland cement. Browning Undercoat plaster made from gypsum and sand. It replaced lime and sand ‘coarse stuff’. Now generally superseded by pre-mixed lightweight plasters (not appropriate to damp situations). Cement Usually Portland cement, so called because it resembles Portland stone when set. It is a mixture of chalk and clay burnt in a kiln. When mixed with water, it hardens in a process known as hydration. Dash External rendering thrown onto a wall by hand or applicator. Dry dash Coarse aggregate thrown onto a wet render coat, giving an exposed aggregate finish.

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Dry hydrated lime Ordinary (non-hydraulic) lime produced as a dry powder by adding just enough water to slake the quicklime (adding more water produces lime putty). Hydrated lime is typically used in cement:lime:sand mixes to improve workability and flexibility. Gypsum A solid white mined mineral, the main constituent of which is calcium sulphate, used as a binder in gypsum plaster. Gypsum plaster Plaster made of gypsum with lightweight aggregates and a retarder. It is unsuitable for external work or damp areas. It is used as a smooth finishing coat. Hemihydrate plaster A plaster made by gently heating gypsum to drive off most of its chemically combined water to become half-hydrated. In its pure form, it is plaster of Paris, but with the addition of retarders, such as keratin, it becomes the basic material for all gypsum plaster, and is known as retarded hemihydrate plaster. Hydrated lime Quicklime slaked with water. Hydraulic lime Lime that can set in the absence of air under water. It is made by burning lime with up to 22% clay. It is widely available in bagged powdered form and conveniently similar in the handling of cement for masons unused to lime putties. Keene’s cement Hard-burnt anhydrous (water-free) gypsum mixed with alum to form a plaster, which can be trowelled to a smooth, intensely hard finish. Lightweight plaster Plaster with lightweight aggregates such as expanded perlite combined with retarded hemihydrate plaster; has low shrinkage and is thermally insulating (not suitable in damp areas). Lime Chalk or limestone burnt in a kiln to 825°C or more. Lime putty Hydrated lime soaked to give it plasticity. Used for lime plasters, renders, mortars, grouts and limewash.

Materials and components 323

Mortar A mixture of sand, cement/lime and water, used primarily for bedding and pointing brickwork, laying floor tiles, and as undercoats to plaster and final coats of external walls. Non-hydraulic lime High calcium lime made by slaking relatively pure limestone. Mortars and renders made from this lime set slowly and are relatively soft, but accommodate normal building movement well and have high levels of vapour permeability and porosity. Pebble dash A dry dash finish in which clean washed pebbles are pushed into wet render and left exposed. Plaster Usually gypsum plaster for interiors, or cement render for exterior work. Pozzolana A natural volcanic silica dust originally from ­Pozzuoli, Italy. When mixed with lime, it sets hard, even under water, making Roman cement. The term pozzolanic additive now includes other aggregates, such as pulverised fuel ash and brick dust, which have similar hydraulic properties. Quicklime Lime before it has been slaked. It reacts strongly with water to produce hydrated lime. Rendering Mortar undercoats and finishing coats for external walls and to receive tiling in wet areas. Retarder Added to cement, plaster or mortar to slow down the initial rate of setting by inhibiting hydration. Spatter dash Cement and sand in a very wet mix, sometimes with a binding agent, flicked on in small blobs with an applicator. Used to create a key for backgrounds with poor suction. Stucco Smooth rendering, originally lime and sand but now cement lime mortar. Often with decorative mouldings shaped to imitate rusticated masonry or column embellishments. Tyrolean finish A spattered textured render achieved by being thrown against a wall with a hand-operated applicator. Sources: Illustrated Dictionary of Building (published by Routledge)

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Pre-mixed plasters Pre-mixed plasters are made from gypsum, which is a natural mineral deposit – calcium sulphate dihydrate. They should conform to BS EN 13279-1:2008 BS EN 13279-2:2014 Specification for gypsum binders and gypsum plasters. Pre-mixed plasters should not be used in continuously damp or humid places, nor should they be used where the temperature exceeds 43°C. Gypsum plasters are unsuitable for external work because gypsum is partially soluble in water. Gypsum plasters can be badly affected by dampness: lime- or cement-based plasters may perform better in such situations. British Gypsum ‘Thistle’ plasters are in three categories: Undercoat plasters Thistle Dri-Coat

Gypsum plasters Thistle Bonding 60 Thistle Bonding Coat

Thistle Hardwall

Thistle Undercoat

A cement-based undercoat plaster for old walls, where plaster has been removed and a chemical DPC inserted Cut repair time for damaged walls with a patching plaster that sets in just 60 minutes An undercoat plaster for low suction backgrounds such as plasterboard, concrete or other surfaces treated with Thistle Bond-It An undercoat plaster with highimpact resistance and quicker drying surface. May be applied by hand or machine to most backgrounds Repair damage up to 11 mm deep

Materials and components 325

Gyproc Easifill 20 Gyproc Easifill 60 Normal thickness One coat plasters Thistle Universal OneCoat Thistle OneCoat

Normal thickness Finish plasters Thistle MultiFinish Thistle BoardFinish Thistle ProDuraFinish

Thistle ProMagnetic Plaster

Repair small holes and cracks quickly and easily Repair walls or fill joints in plasterboards with an all-in-one product 11 mm to walls, up to 8mm to ceilings plus 2 mm of finish plaster One coat plaster suitable for most backgrounds with a smooth white finish. May be applied by hand or machine Thistle One Coat Plaster is an undercoat and finish rolled into one. A single repair product for patching jobs like filling large holes and chasing in 13 mm to walls, up to 10 mm to ceilings A versatile final coat plaster for a wide range of backgrounds For low to medium suction backgrounds such as plasterboard or Thistle DriCoat Gypsum finish plaster specially formulated for increased resistance to accidental damage. Enables significantly longer maintenance intervals and lower long-term cost A finish coat plaster that contains properties to attract magnets – turn a wall into an interactive area, can hang pictures without fixings

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Undercoat plasters – continued Thistle PureFinish

Thistle SprayFinish

ThistlePro FastSet Finish

Normal thickness

Thistle PureFinish contains ACTIVair technology, designed specifically to decompose formaldehyde emissions into nonharmful inert compounds, boosts indoor air quality to help improve health and comfort; turns harmful emissions into inert compounds; contributes BREEAM points to management plans; works with breathable emulsion paints; offers the same fire and durability performance as standard plasters Thistle SprayFinish is a gypsum finishing plaster designed for skim finishing large wall areas using a spray machine to automatically mix and apply the finishing plaster more quickly ThistlePro Fastset Finish is a quick setting gypsum finish plaster that provides a smooth highquality surface finish. Ideal for patch and repair jobs as well as smaller internal walls and ceilings. It provides a durable base for applying decorative finishes 2 mm

Source: British Gypsum Ltd www.british-gypsum.com

Materials and components 327

Metals Metals commonly used in the construction industry Name

Symbol

Atomic numbera

Description

Aluminium

Al

13

Lightweight, fairly strong metal normally used as an alloy for castings, sheet or extrusions

Brass

–

–

An alloy containing zinc and more than 50% copper. Easily formed, strong and corrosion-resistant

Bronze

–

–

An alloy of copper and tin, sometimes combined with other elements. Hard and corrosion-resistant

Copper

Cu

29

A durable, malleable metal, easy to form but hardens quickly when worked and needs annealing. Good electrical and thermal conductivity

Iron

Fe

26

A heavy metal, the fourth most abundant element on the earth’s crust. Almost always alloyed with other elements

Lead

Pb

82

The heaviest of the heavy metals, dull blue grey, easily fusible, soft, malleable and very durable

Stainless steel

—

—

An alloy of steel and up to 20% chromium and 10% nickel. Corrosion-resistant but more difficult to fashion than carbon steel

Steel

—

—

An alloy of iron and a small, carefully controlled proportion of carbon, normally less than 1%

Tin

Sn

50

A metal nearly approaching silver in whiteness and lustre, highly malleable and taking a high polish. Used to form alloys such as bronze, pewter, etc.

Titanium

Ti

22

Relatively light, strong transitional metal found in beach sands. As strong as steel but 45% lighter, and twice as strong as aluminium but 60% heavier

Zinc

Zn

30

A hard, brittle, bluish white metal, malleable and ductile between 95°C and 120°C obtained from various ores. Corrodes 25 times more slowly than steel

a

A ratio of the average mass of atoms in a given sample to one-twelfth the mass of a carbon 12 atom.

Bi-metal compatibility Contact between dissimilar metals should be avoided where possible. Where contact cannot be avoided and moisture may be present, metals should be separated as shown in the table below. Stainless steel

Mild steel

Copper/bronze

Cast iron

Aluminium

Stainless steel











Mild steel











Copper/bronze











Cast iron











Aluminium











 = may be in contact;  = may be in contact in dry conditions;  = should not be used in contact.

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Metals: some commonly used industrial techniques Aluminium extrusions Aluminium sections made by pushing aluminium through a series of dies until the required intricate shapes are obtained. Brazing A simple, inexpensive way of joining two pieces of hot metal with a film of copper–zinc alloy, a hard solder also referred to as the filler. Brazed steel joints are less strong than welded joints. Cast iron An alloy of iron and carbon containing more than 1.7% carbon (normally 2.4–4%). Components are made by casting from remelted pig (ingot) iron with cast iron and steel scrap. It has low melting point and flows well, and is useful for more intricate shapes than steel or wrought iron. Forging (smithing) The act of hammering metal into shape when it is red-hot, traditionally on an anvil. Formerly referred to iron, but now includes steel, light alloys and non-ferrous metals worked with power hammers, drop stamps and hydraulic forging machines. Shot blasting Cleaning metal surfaces by projecting steel shot with a jet of compressed air. Used as a preparation for painting or metal coating. Sweating Uniting metal parts by holding them together while molten solder flows between them, as in a capillary joint, which is a spigot and socket joint in metal tubing. Tempering Reducing the brittleness of steel by heating and slow cooling (annealing). Welding Joining pieces of metal made plastic or liquid by heat and/or pressure. A filler metal whose melting temperature is the same as that of the metal to be jointed may also be used. Arc welding fuses metals together with an electric arc, often with a consumable metal electrode. Wrought iron Iron with a very low carbon content ­(0.02–0.03%). It is very malleable and cannot be hardened by tempering. It is soft, rusts less than steel but is more expensive,

Materials and components 329

so it has largely been replaced by mild steel. Used for chains, hooks, bars and decorative ironwork.

Metal finishes Anodising A protective durable film of oxide formed by dipping an aluminium alloy object into a bath of chromic or sulphuric acid through which an electric current is passed. The film may be coloured with dyes. Chromium plating The electrolytic deposition of chromium onto other metals to produce a very hard, bright finish. When applied to iron or steel, chromium adheres best if a layer of nickel or copper is first deposited. Galvanising A coating for steel that is quite durable and gives good protection against corrosion in moderate conditions. Components are hot dipped in molten zinc or coated with zinc electrolytically. Powder coating Polyester, polyurethane, acrylic and epoxy plastics sprayed and heat-cured onto metals such as aluminium or galvanised steel for a 50–100-micron thick film. Finished components can also be hot dipped in polyethylene or nylon for a 200–300-micron thick film. Sherardising A protective coating of zinc on small items such as nuts and bolts, which are rolled for ten hours in a drum containing sand and zinc dust heated to 380°C. The coating is thin but the zinc diffuses into the steel to form a zinc alloy. It does not peel off, distorts less and is more durable than galvanising. Stove enamelling Drying of durable enamel paints by heat, normally over 65°C, either in a convection oven or by radiant heat lamps. Terne coating Tin-coating of stainless steel (typically roofing or cladding) to produce a highly durable low reflectance finish that weathers to a matt pale grey. Vitreous enamelling A glazed surface finish produced by applying powdered glass, dry or suspended in water, which is fused onto metal. This is a true enamel – not enamel paint.

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Insulation Thermal insulation Next to a vacuum, trapped air or inert gas is the most effective way to trap heat, so all insulants work in this way from the most natural, like sheep’s wool, to the most technologically sophisticated oil-based materials like phenolic foam. Vacuum materials are also now available but are both costly and ‘fragile,’ so of limited usefulness. Construction insulants have to perform in different circumstances – wet and dry for example – so different ­ ­materials are appropriate. Some ‘insulants’ also function in other ways such as aerated concrete blockwork walls; others such as multi-foils, combine air-trapping technology with reflectance to resist heat ­transfer  – though some of the multi-foil manufacturers’ performance claims have been shown to be exaggerated. The relative performance of insulants is measured either by their conductivity (‘K-value’) – the lower the better – or by their resistivity (‘R-value’) – the higher the better. In the UK, K-­ values and their relatives, U-values (thermal transmittance, see p. 149), are used, whereas in the US, resistivity and R-values (thermal resistance of various thicknesses of a material) are the norm.

High High Medium High

High

Low

0.07 0.055 0.14 0.11

0.065

0.035/CbS*

0.033–0.04

0.033–0.04

0.035 0.038

Glass wool

Mineral wool

Sheep’s wool Cellulose fibre

High High

High

High

Medium

0.16

Aerated concrete Hempcrete Strawbale Softwood Woodwool slabs Vermiculite granules Multi-foils

Vapour permeability

K-value

Insulants

Med/ LiV* Med/ LiV* High Very poor

Good/ LiV* High/*

Medium Medium Low Medium

High

None None

Varies

None

None

None

Medium Medium High High

High

Moisture Rigidity tolerance

CHARACTERISTICS AS INSULANTS

Table of insulation materials

Yes

Infill Yes Yes Yes

No No

Yes Yes

Cavity insul Yes

Protected Yes cavity insul Cavity insul Yes

No

Infill Yes No No

No No

No

No

No

No

Medium Yes (ltd) Yes Yes

Yes

For timber Structural frames/ use roofs

Wall blocks No

For masonry walls

High

High

Very high

High

Very low Very Low Medium

High

Embodied energy

Animal Low Plant and Low recycled

Mineral

Mineral

Oil

Medium Plant Plant Plant and mineral Mineral

Mineral

Origin

Low Low

High

High

High

Medium

High Low Very low Low

High

CO2 impact

High Low to Medium

Low

Very high Low

Low

High V. low Medium Medium

Medium

Relative cost

Materials and components 331

High

0.02

0.02

0.015

0.007

Phenolic

Aerogel

Vacuum panels

High

High

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Cavity insul Yes

No

No

No

No

No

No

No

No

No

For timber Structural frames/ use roofs

Cavity insul Yes

No

Sheathed cavity insul Medium Protected cavity insul Medium Protected cavity insul Medium Protected cavity insul Medium Protected cavity insul Varies Cavity insul

Medium

Medium

Low

None

For masonry walls

Oil

Oil

Oil

Oil

Oil

Oil

Oil

Oil

Recycled (oil)

Origin

High

High

High

High

High

High

High

High

High

Embodied energy

High

High

High

High

High

High

High

High

Medium

CO2 impact

V.high

V.high

High

High

Medium to high High

Medium

Low

Medium

Relative cost

Notes: LiV: Loss in insulating value when wet; quilts permanently if saturated; batts and slabs recover when dried out. CbS: Assumes cavities both sides: including these, typical 30 mm thick multi-foils occupy approx 60 mm and perform as well as 60 mm mineral fibre. Protected: These insulants not yet marketed for full fill-cavity insulation, so they require cavity, membrane or polystyrene cavity board protection.

None

Medium

Low

High

Medium

0.022–0.028 None

Low

High

0.022–0.028 None

Low

High

0.028–0.036 None

0.032–0.04

High

Moisture Rigidity tolerance

Med/ LiV* High

0.04

Plastic wool

Vapour permeability

Expanded polystyrene Extruded polystyrene Polyeurethane foams Isocyanurate foams Phenolic

K-value

Insulants

CHARACTERISTICS AS INSULANTS

Table of insulation materials – continued

332 Architect’s Pocket Book

Materials and components 333

Although there are substantial differences in insulating performance between, say, phenolic foam (k:0.02) and sheep’s wool (k: 0.039), other factors such as vapour permeability and moisture control in relation to adjacent materials make comparison more complex. In many situations, especially in existing buildings, the space or cost implications of using more environmentally benign insulants such as recycled cellulose fibre or sheep’s wool may be prohibitive and the long-term environmental value of using a much higher performance, oil-based insulant with high embodied energy may be worthwhile; however, for Listed Buildings, some officers may prevent the use of “unnatural” materials. Although cavity wall insulation is a relatively low cost and reliable means of substantially improving insulation of cavity-walled buildings, the small size – usually 50–70 mm – of the existing cavities and the limited choice and insulation value of reliable cavity wall insulants – blown mineral fibre and blown polystyrene beads – mean that most installations still do not achieve compliance with current Building Regulations. For higher performance, internal or external insulation – for example, with 125 mm of phenolic foam board – can bring U-values right down to Passivhaus standards below 0.15. Each installation is disruptive and expensive with internal insulation requiring refitting of internal joinery, plaster details and services on outside walls, as well as perimeter floor dismantling to allow insulation between joists. External insulation has the benefit of leaving interiors undisturbed and potentially still occupied but changes the external appearance and requires full height access scaffolding, as well as refitting of rainwater goods, roof eaves details, window sills etc.; it is also subject to weather delays. Its benefit in comparison with internal insulation is that the thermal mass of existing masonry walls remains within the building’s thermal envelope and cold bridging by partitions is avoided.

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In new buildings, materials such as hemp–lime concrete or aerated concrete that combine thermal insulation, acoustic insulation, thermal mass and structural function may prove ideal, whereas for thermal dry lining to an existing building, minimising thickness – with maximum insulation – may be the overriding criteria for selection. In new construction, insulation choice may be ‘system driven,’ for example, most SIPS manufacturers use petrochemical foam insulants for high performance in relatively thin panels whereas others use recycled cellulose fibre in thicker panels with fibreboard external sheathing for breathability.

Insulation and condensation One of the most critical details for successfully insulating buildings, beyond the selection of the insulant itself, is the control of water vapour from human activities within the building, i.e., breathing, sweating, washing, cooking, etc. As buildings have been better sealed to save energy, this has become even more crucial. Since extract facilities, whether passive or fan-powered, cannot be relied upon to be either wholly effective or correctly controlled, it is important that there is a rising ‘gradient of permeability’ towards the building’s outside skin so that the building can ‘breathe’ without causing – or at least without trapping – condensation at its cold exterior. The worst examples of this problem occur with an impermeable outer skin such as flat roofing or sheet metal cladding and the best examples of its avoidance are in fully permeable traditional lime-mortared masonry or earth walling, or in open-vented timber cladding to framed structures. Another problem area is in traditional roof spaces covered with bitumen felt sarking where increased standards of insulation at ceiling level have dropped the roofspace temperature and, in many cases, restricted the flow of eaves ventilation to the extent that water vapour rising through ceilings condenses on the cold underside of the felt sarking and drips onto the insulated ceiling below; an extreme example of this problem often occurs

Materials and components 335

where halogen downlights – necessarily vented – are installed in a bathroom ceiling and condensation symptoms can be as severe as a serious roof leak. There are two ways to deal with the problem (for the least permeable outer skins as in flat roofing, both are needed). The first is to ventilate an air space between the insulation and the external skin so that the vapour and condensation has a chance to evaporate; the second is to introduce a ‘vapour check’ – most commonly sheet polythene but sometimes integral with lining materials – on the warm side of the insulation to reduce the amount of vapour reaching the cold surface. It is important that the vapour check is not expected to be perfect: although ‘vapour barriers’ are theoretically possible, they require careful design and thorough and conscientious workmanship on site, which cannot realistically be expected in most circumstances. To pre-empt the problem, it is possible to simulate building fabric performance using WUFI Pro or similar software that provides a much more realistic assessment of hygrothermal behaviour than the steady-state condensation prediction calculation using the Glazer method.

Roofing and cladding Tiles, slates and shingles Typical minimum pitches Bituminous shingles Cedar shingles Cedar shakes Clay tiles – plain Clay tiles – interlocking Concrete tiles – plain Concrete tiles – interlocking Fibre-cement slates Natural slates Stone slates – sandstone and limestone

17° 14° 20° 35° 15 35° 15 20° 22.5° 30°

Note: In areas of high winds and driving rain, these minimum pitches may not be advisable. Lower pitches may be possible with hook fixings and correct underlays.

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Roofing slates Type

Size (mm)

Princesses Duchesses Small duchesses Marchionesses Wide countesses Countesses Wide viscountesses Viscountesses Wide ladies Ladies

610 × 355 610 × 305 560 × 305 560 × 280 510 × 305 510 × 255 460 × 255 460 × 230 405 × 255 405 × 205

Grade Best Medium strong Heavies

No./m2 Batten gauge

No./m2 Batten gauge

No./m2 Batten gauge

50 mm 10.06 11.71 12.86 14.01 14.26 17.05 19.13 21.21 22.16 27.56

75 mm 10.55 12.28 13.55 14.76 15.11 18.07 20.42 22.64 23.77 29.56

100 mm 11.05 12.86 14.26 15.53 15.99 19.13 21.79 24.15 25.80 32.09

lap 280 280 255 255 230 230 205 205 177 177

Thickness

Weight

4 mm 5 mm 6 mm

31 kg/m2 35 kg/m2 40 kg/m2

lap 267 267 242 242 217 217 192 192 165 165

lap 255 255 230 230 205 205 180 180 152 152

Slates are now more commonly available in metric sizes and 6, 7, 8 and 10 mm thicknesses. BS 5534:2014+A2:2018 Slating and Tiling

Roofing tiles Clay PLAIN

Clay interlocking SINGLE PANTILE

Concrete interlocking DOUBLE ROMAN

Concrete interlocking DOUBLE PANTILE

Concrete interlocking FLAT SLATE

Size mm

265 × 165

380 × 260

418 × 330

420 × 330

430 × 380

Pitch min Pitch max Headlap min Gauge max Cover width Coverage Weight @ m  ax gauge Weight per 1000

35° 90° 65 mm 100 mm 165 mm 60/m2 77 kg/m2

22.5° 90° 65 mm 315 mm 203 mm 15.6/m2 42 kg/m2

17.5° 90° 75 mm 343 mm 300 mm 9.7/m2 45 kg/m2

22.5° 44° 75 mm 345 mm 296 mm 9.8/m2 46 kg/m2

17.5° 44° 75 mm 355 mm 343 mm 8.2/m2 51 kg/m2

1.27 tonnes

2.69 tonnes

4.69 tonnes

4.7 tonnes

6.24 tonnes

Materials and components 337

Coverage relates to tiles laid at the maximum gauge. The number of tiles will increase as gauge decreases. Weights are approximate and relate to tiles laid at maximum gauge. Weights will increase as gauge decreases.

Sarking membranes Sarkings are weatherproof membranes laid over rafters and below battens to draughtproof and weatherproof the roof against driving rain or powder snow that may penetrate the tiles or slates. Traditional sarkings of reinforced bitumen felt have been largely superseded by lighter, breathable sarkings that can be laid to form an effectively draught-proofed roof but still allow free dispersal of water vapour to avoid roof space condensation; such materials generally avoid the need for eaves, ridge and roof slope ventilators. Where they are laid directly over insulation between rafters, or over a permeable sarking board, tiling battens are raised clear of the sarking membrane by 25 × 50 counter battens nailed down to the tops of the rafters. Where bats use roofspaces or roof tiling, use of traditional bitumen sarking may be compulsory since breathable sarkings have been found to ensnare bats.

Battens All tiles and slates may be fixed to 50 × 25 mm battens with supports at maximum 600 mm centres. Battens for plain clay tiles may be reduced to 38 × 25 mm when fixed at 450 mm centres. Consult manufacturer’s information for weights and laps of tiles or slates.

Matching accessories Accessories made in various materials to match – or colour match – the tiles and slates include the following: segmental and angle ridge tiles, mono ridge tiles, specific angle ridge and

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hip tiles, ornamental ridge tiles, block-end ridge tiles, cloaked verge tiles, ridge ventilation tiles, ridge gas flue tiles, vent tiles and slates for soil pipes and fan ducts.

uPVC/Polypropylene accessories These include devices for fixing ridge and hip tiles without mortar and for providing under-eaves ventilation and abutment ventilation for lean-to roofs. Sources: Redland Pitched Roofing www.bmigroup.com Marley www.marley.co.uk Klober www.klober.co.uk

Shingles and shakes Shingles are taper sawn from blocks of western red cedar or, less often, oak and sweet chestnut and have a life expectancy of 50 years. A+ rated in the Building Research Establishment (BRE) Green Guide. No. 1 grade Blue Label is the premium grade for roofs and walls. Shakes are similar but are split rather than sawn.

Size The standard size FIVE X or XXXXX is 400 mm long in varying widths from 75 to 350 mm. The thickness tapers from 3 mm at the head to 10 mm at the butt, or tail, end. Other sizes are Perfections, 450 mm long and Royals 600 mm long.

Colour Reddish brown, fading to silver-grey when weathered.

Materials and components 339

Treatment Shingles are available untreated, tanalised or with fire retardants. Tanalising is recommended for external use. Some local authorities may insist on a fire-retardant treatment depending on the nature of the location.

Fancy butt These are shingles with shaped butt ends such as diamond, half round, arrow, fish scale, hexagonal, octagonal, etc. These are suitable for pitches over 22°.

Accessories Pre-formed cedar hip and ridge units 450 mm long are available that are normally fixed over a 150 mm wide strip of F1 roofing felt.

Pitch 14° minimum pitch 14° to 20° maximum recommended gauge = 95 mm Over 20° maximum recommended gauge = 125 mm Vertical walling maximum recommended gauge = 175 mm

Coverage Shingles are ordered by the bundle. One bundle at 14–21o covers approximately 1.8 m2 @ 95 mm gauge. Minimum side lap 38mm.

340 Architect’s Pocket Book

Weight 400 mm long @ 95 mm gauge Untreated   8.1 kg/m2 Tanalized 16.19 kg/m2 With fire-retardant   9.25 kg/m2

Battens Shingles are fixed to 38 × 25 mm battens with a 6 mm gap between adjacent shingles using stainless steel nails – two nails to each shingle. Nails are positioned 19 mm in from side edge and 38 mm above the butt line of the course above. They should comply to BS 5534:2014 + A2;2018. JB-RED battens, 38 × 25 supported at 450ccs or 50 × 25 supported at 600ccs. A vapour-permeable type underlay that meets BS 5534:2014 + A2;2018 is recommended. For warm roofs, counter battens will be required between the shingle batten and the insulation board.

Flashing Bituminous paint should be applied to metal flashings to avoid contact between shingles and metal and subsequent staining. As an alternative, glass-reinforced plastic (GRP) valleys and flashings may be more suitable. Source: www.marley.co.uk

Materials and components 341

Thatch Water reed Phragmites communis is grown in British and Continental rivers and marshes. Norfolk reed is the finest thatching material. Water reed thatch is found in East Anglia, the South Coast, S Wales and NE Scotland. Combed wheat reed Winter wheat straw, nowadays called ‘Maris Huntsman,’ is passed through a comber. Butt ends are aligned to form the face of thatch. Found in the West Country. Sometimes called Devon Reed. Long wheat straw Threshed wheat straw, wetted and prepared by hand. Ears and butts are mixed up and a greater length of stem is exposed. Found in central, southern and SE regions of England. Pitch Recommended pitch is 50°, minimum 45° and maximum 60°. Weight Approximately 34 kg/m2. Netting This is essential to preserve the thatch from bird and rodent damage. 20 or 22 gauge galvanised wire mesh should last 10–15 years. Sedge Cladium mariscus is a marsh plant with a rush-like leaf. It is still used in the fens and for ridges to Norfolk reed thatch.

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Heather Calluna vulgaris was once in general use in non-corn growing areas such as Dartmoor and the NE and can still occasionally be seen in Scotland. Life expectancy Varies substantially according to material used, roof pitch, exposure, and quality of thatching: best Norfolk reed thatch can be expected to last between 30 and 50 years, whereas wheat straw thatch may last from 15 to 30; ridges and other detail work may require intermediate repair.

Thatching data

Length Coat thickness Coverage

Lifespan Battens (38 & 25 mm) centres

Water reed

Combed wheat reed

0.9–1.8 m 300 mm 80–100 bundles / 9.3 m2 (1 bundle = 300 mm Ø) 50–70 years 255 mm

1.2 m 1.2 m 300–400 mm 400 mm 1 tonne/32 m2 1 tonne/36.6 m2

20–40 years 150–230 mm

Long wheat straw

10–20 years 150 mm

Materials and components 343

Metal roofing and cladding Metal roofing includes a wide range of materials, detailing, installation, aesthetics and cost on widely differing buildings, ranging from intricate lead detailing on historic buildings to the lowest cost profiled steel cladding of warehouses and barns. The one characteristic that all roofing metals have in common is that they are by nature impervious – to vapour as well as moisture – so they require thorough protection against condensation either by well-ventilated substrates for ‘cold roofing,’ or by effective vapour control layers for ‘warm roofing’. Roofing metals and their installation fall into two groups – metals fully supported by a deck, and profiled metals spanning between supports; a few metals, principally aluminium and stainless steel are used in both ways. Lead, copper and zinc – fully supported metals:

Lead Lead sheet for the building industry may be either milled lead sheet to BS 12588:2006 or machine cast lead sheet covered by Agrément Certificate 86/1764. Cast lead sheet is also still made by specialist firms using the traditional method of running molten lead over a bed of prepared sand. This is mainly used for replacing old cast lead roofs and ornamental leadwork. Milled lead sheet is the most commonly available having about 85% of the market. There are no significant differences in the properties, performance or cost between cast and milled lead sheet. Cast lead sheet at first appears slightly darker and less shiny than milled, but is indistinguishable six months after installation.

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Thickness Choice of thickness depends upon use. Additional thickness will cope better with thermal movement, mechanical damage and resist windlift. It will also provide more material for dressing and bossing into shape.

Sizes Lead sheet is specified by its BS code number or its thickness in millimetres. The range of metric sizes corresponds closely to the former imperial sizes that were expressed in lb/sq.ft. The ends of lead coils may also carry colour markings for easy recognition as shown below. BS Code no.

Thickness (mm)

Weight (kg/m2)

Colour code

Application

3 4 5

1.32 1.80 2.24

14.99 20.41 25.40

Green Blue Red

6

2.65

30.05

Black

7 8

3.15 3.55

35.72 40.26

White Orange

Soakers Soakers, flashings Soakers, flashings, gutters, wall and roof covering Gutters, wall and roof coverings Gutters, roof coverings Gutters and flat roofs

Sheet size Lead sheet may be supplied cut to size or as large sheets 2.4 m wide and up to 12 m long. For flashings, coils are available in code 3, 4 and 5 lead and in widths from 150 to 600 mm in steps of 50 mm, and 3 m or 6 m in length.

Materials and components 345

Weight To determine the weight of a piece of lead, multiply the length × width (m) × thickness (mm) × 11.34 = kgs.

Joints Maximum spacing Flat roof 0°–3°

Pitched roof 10°–60°

Pitched roof 60°–80°

Wall cladding

BS Joints code with no. fall

Joints Joints across with fall fall

Joints Joints across with fall fall

Joints Vertical across joints fall

Horizontal joints

4 5 6 7 8

1500 2000 2250 2500 3000

1500 2000 2250 2400 2500

1500 2000 2250 2250 2250

1500 2000 2000 2250 2250

500 600 675 675 750

500 600 675 675 750

500 600 675 675 750

500 600 600 650 700

Parapet and tapered gutters BS code no. 4 5 6 7 8

Maximum spacing of drips (mm)

Maximum overall girth (mm)

1500 2000 2250 2700 3000

 750  800  850  900 1000

Flashings To ensure long life, flashings should never exceed 1.0 m in length for code 3 lead and 1.5 m in length for codes 4 and 5. Flashings should lap a minimum of 100 mm horizontally. Vertical laps should be a minimum as shown below.

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Roof pitch

Lap mm

Roof pitch

Lap (mm)

11° 15° 20° 30°

359 290 220 150

40° 50° 60° 90°

115 100  85  75

DPCs Code 4 lead sheet is suitable for most DPCs. This may be increased to code 5 where a 50 mm cavity is exceeded. Lead DPCs should be covered both sides with bituminous paint to avoid the risk of corrosion from free alkali in fresh Portland cement.

Condensation In well-heated buildings, warm moist air may filter through the roof structure and condense on the underside of the lead covering, leading in the long term to serious corrosion. Ensure that there is ventilation between the timber decking supporting the lead and any insulation.

Corrosion Lead may be used in close contact with copper, zinc, iron and aluminium. It may be attacked by organic acids from hardwood and cedar shingles. Sources: Lead Sheet Association www.leadsheet.co.uk Midland Lead Manufacturers Ltd www.midlandlead. co.uk Royston Lead Ltd www.roystonlead.com

Materials and components 347

Copper roofing and cladding Copper is classified as a noble material. It has a long life (75– 100 years), is corrosion-resistant and is lightweight and workable. It is more resistant to creep on vertical surfaces than lead and can cover flat or curved surfaces. Copper for roofing, flashings and DPCs should conform to BS EN 1172: 2011. Copper strip

=

Copper sheet = Copper foil

=

0.15–10 mm thickness, of any width and not cut to length. It is usually supplied in 50 kg coils. It is cheaper than sheet 0.15–10 mm thick flat material of exact length and over 450 mm wide 0.15 mm thick or less

Normal roofing thickness is 0.6 mm; 0.45 mm is now considered sub-standard; 0.7 mm is used for pre-patinated copper sheet and for sites with exposure to high winds. Pre-patinated copper was first used in Germany in the late 1980s; 0.7 mm thick copper sheets have a chemically induced copper chloride patina. This produces a blue/green appearance, which is more even than the streaky appearance of some naturally induced patinas. The sheet size is limited to 3 m in length so it is not suited for longstrip roofing.

Longstrip copper roofing This method was introduced to the UK from the Continent in 1957. Factory or site formed copper trays are attached to a fully supporting deck with standing seams or roll joints. The copper used has a harder temper and the special expansion clips at the seams allow longitudinal movement. The main advantage is the absence of cross joints on sloping roofs and drips on flat roofs, which saves labour and reduces cost. Suitable for pitches from 6° to 90°.

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Bay size = 525 mm centres × 10.0 m. In exposed sites, bay widths should be reduced to 375 mm centres. After 10 m in length, 50 mm high drips should be placed across fall. Weight 0.6 mm @ 525 mm centres = 5.7 kg/m2 Falls Minimum fall for any copper roof 1:60 (17 mm in 1 metre) Minimum fall for copper gutters 1:80 (12 mm in 1 metre) Parapet gutters Maximum length of any one sheet is 1.8 m. Thereafter 50 mm minimum deep drips should be introduced. Continuous dripping of rainwater from tiled or slated roofs may perforate gutter linings. Sacrificial strips should be placed in gutters and replaced when worn. Step flashing Maximum 1.8 m long with welted joints. Single-step flashings, with each end overlapping 75 mm, may be easier to repair where small areas corrode. Laying Lay with underfelt of impregnated flax felt with ventilation to space or voids under decking to avoid condensation. Fixings are copper clips (cleats) secured by copper nails or brass screws to decking. Avoid any use of soft solder to prevent electrolytic action. Use mastic between apron flashings and pipes. DPCs Copper is highly suitable for DPCs as it is flexible and not attacked by cement mortar. Joints should overlap 100 mm.

Materials and components 349

Corrosion Copper can be corroded by sulphur dioxide from chimneys unless stacks rise well clear of roof. Copper will corrode when in contact with damp wood impregnated with some fire retardants and from the run-off from western red cedar cladding. Ammonia (from cats’ urine) may cause cracking. Copper will corrode aluminium, zinc and steel if in direct contact or indirect contact from water run-off. Copper may leave green stains on masonry. Patina This takes 5–20 years to form, depending on location. It is a thin, insoluble layer of copper salts that protects the underlying material from atmospheric attacks. It is generally green but may look buff or black in soot-laden air.

Traditional copper roofing There are two traditional methods of copper roofing: Batten rolls 40 mm high-shaped wooden rolls are laid parallel to bay slope. Bay sheets are the turned up sides of rolls and covered with copper capping strip. Ridge rolls are 80 mm high. Suitable for flat and pitched roofs. Bay size = 500 mm centres × 1.8 m. Standing seams These are suitable for side joints on roofs that are not subject to foot traffic, and may be used for roofs over 6°. The seams are double welted joints 20–25 mm high. Bay size = 525 mm centres × 1.8 m.

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Cross joints At right angles to wood rolls or standing seams. They should be double lock cross welts. Above 45° pitch, single lock cross welts may be used. Stagger cross joints in adjacent bays to avoid too much metal at seams. On flat roofs, drips 65 mm deep should be introduced at maximum 3 m centres (see Falls above). Maximum sheet sizes Sheet sizes should not exceed 1.3 m2, reduced to 1.10 m2 where 0.45 mm thick sheet is used. Sources: Copper Development Association www.copperalliance.org.uk Antimicrobial copper Copper is a powerful antimicrobial with rapid, broad-­ spectrum efficacy against bacteria and viruses, including MRSA, E.coli and norovirus. It shares this benefit with a range of copper alloys – such as brasses and bronzes – ­forming a family of materials collectively called ‘antimicrobial copper’. In hospital trials, antimicrobial copper surfaces have been found to harbour >80% less contamination than non-­ copper surfaces. Touch surfaces made from solid antimicrobial copper are already used by airports, train stations and healthcare facilities around the world to reduce the spread of infections, supporting key infection control measures such as good hand hygiene and regular surface cleaning and disinfection. Sources: www.antimicrobialcopper.org

Materials and components 351

Zinc roofing and cladding Zinc is versatile, ductile, economical, has moderate resistance to atmospheric corrosion and is suitable for marine locations. Zinc is produced in rolls for both roofing and cladding. It is available as mill finished natural zinc or pre-weathered in a variety of colours. Roofing Standing seam roof system: Types of roof construction – warm non-vented or cold vented Pitches 3–90 degrees, panels up to 13 m long Seams are typically 430, 530, 600 ccs but non-standard bays of 60–600 mm can be produced. Seam height is 25 mm Standing seam zinc roofing will not give a perfectly flat finish. However, by reducing panel width and increasing zinc thickness, unevenness will be reduced. Narrower panels are also recommended in exposed areas with high wind loads. Facades cladding Initially traditional roofing systems such as standing seam panels were installed as ‘roofs on walls’. Flat lock panels have also been installed for many decades. Both of these systems require vented continuous substrates and are commonly installed by traditional hard metal roofing contractors. Fully supported on ply or open gap softwood boards – ­standing seam, flatlock or ADEKA Standing seam max panel size 430 × 4000 mm; flatlock can be square, rectangular or diamond max width 600 mm, max length 3000 mm; ADEKA a diamond aesthetic with small preformed elements 400 × 400 mm.

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A rainscreen façade is an outer skin that is back-ventilated by an air space that is 38 mm deep. The system can be used on both new build and renovation but always allows the outer layer to breathe whilst the inner layer deals with thermal insulation and air leakage. All joints are dry and do not use any form of sealant. Panel types: Interlocking up to 333 mm wide; sine wave max panel size 836 × 6000 mm, overlapping max panel size 200 × 3000 mm, MOZAIK 333 – max panel size 2400 × 600 mm depth 40/60/80/100 mm. Corrosion Zinc is non-staining and contact is possible with iron, steel, aluminium, lead and stainless steel. Run-off from unprotected iron and steel may cause staining but no harm. Zinc should not be used directly or indirectly from run-off with copper that will cause corrosion. Zinc may be corroded by contact with western red cedar, oak, sweet chestnut, certain fire retardants and soluble salts in walling materials. Titanium zinc has a long life. Sources: V M Zinc www.vmzinc.com

Aluminium roofing and cladding Aluminium is strong but lightweight and malleable, has a long life and low maintenance. A high proportion of recycled material is used in its manufacture. The most readily available recommended roofing grade is 1050A, which is 99.5% pure aluminium, with H2 temper. 0 temper (fully soft) is suitable for flashings or intricate shaping. See CP 143 – 15: 1973 (2012) for application. Aluminium is normally available in ‘mill finish’ that weathers to a matt grey, staying light in unpolluted areas but darkening in industrial atmospheres. It can also be supplied with a factory applied PVF2 paint in a limited range of colours. Avoid dark, heat-absorbing shades.

Materials and components 353

Thickness 0.8 mm is recommended roofing gauge.

Sheet width 450 mm standard.

Bay width Typically 380 mm; longstrip typically 525 mm; batten roll typically 390 mm.

Bay length Traditional standing seam – 3 m maximum rising to 6 m for roofs pitched above 10°. Longstrip – 10 m maximum is typical but is available up to 50 m.

Weight

0.8 mm @ 525 mm centres = 2.6 kg/m2.

Falls Minimum 1: 60.

Fixings All aluminium, including adjacent flashings and gutters.

Joints Traditional standing seam, longstrip standing seam and batten roll.

Corrosion Aluminium is corroded by contact with brass and copper. Direct contact with and run-off from lead should be protected with a barrier of bituminous paint. Zinc is sacrificial to aluminium that can lead to premature failure of zinc-coated steel fixings. Avoid

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contact with wood preservatives and acidic timbers by the use of polythene barrier membranes.

Stainless steel roofing and cladding Stainless steel is lightweight, can be pre-formed, has a low coefficient of expansion, high tensile strength, can be worked at any time of year, is resistant to corrosion attack by condensation, and has good environmental credentials, being substantially recycled and very long-lasting; it can match and be used alongside lead. Stainless steel for roofing should conform to BS EN ISO 18286: 2010 BS EN ISO 9445: 2010. There are two grades normally used for roofing: Type 304 (Austenitic) Suitable for most UK situations but not within 15 miles of the sea or in aggressively industrial atmospheres – 0.38 mm thick Type 316 (Austenitic molybdenum) Highest grade that is now the standard grade recommended, suitable for all atmospheres – 0.4 mm thick Stainless steel is naturally reflective but low reflectivity is achieved by: Mechanical rolling Terne coating

Rolling sheets under pressure through a set of engraving tools Coated with tin that weathers to form a mid-grey patina similar to lead

Sheet width Coils vary typically 500 mm and 650 mm wide but sometimes still imperial 457 mm (18′) and 508 mm (20″).

Materials and components 355

Bay width Bay width comprises 385 mm and 435 mm centres with standing seams, 425 mm and 450 mm centres with batten rolls.

Bay length Maximum is normally 9 m but it is available up to 15 m. Over 3 m, expansion clips must be used.

Weight

0.4 mm @ 435 mm centres = 4 kg/m2.

Falls Minimum 5° up to 90°. 9° minimum recommended for ­exposed sites.

Joints Traditional standing seam, longstrip standing seam and batten roll. Cross joints between 5° and 12° should be lap lock welt. Cross joints between 13° and 20° should be double lock welt. Cross joints between 21° and 90° should be single lock welt.

Fixings Stainless steel throughout for all clips, nails and screws.

Corrosion Resistant to most chemicals. Hydrochloric acid, used to clean masonry, will cause corrosion. Contact with copper may cause staining but otherwise no harm. Migrant rust marks can occur from the sparks of carbon steel cutting/grinding machines. It is not attacked by cement alkalis, acids in timber or run-off from lichens.

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Profiled sheet roofing: Steel and aluminium: Profiled metal sheet may be used for both roofing and cladding. Profiling thin metal sheet gives stiffness, providing greater strength. The deeper the profile, the stronger the sheet and greater the span. Bolder profiles cast darker shadows and may therefore be preferred aesthetically. Coated steel is lowest in cost but limited in life to the durability of the finish. Aluminium develops its own protective film but is less resistant to impact. Cladding to lower parts of buildings should be protected by guard rails or other devices. Avoid complex building shapes to simplify detailing. Profiled sheets are quick to erect, dismantle and repair. The most common profile is trapezoidal. Curved profiled sheet Radiused corners may be achieved by using crimped profiled sheets. Typical minimum external radius is 370 mm. Noncrimped profiled sheets may be pre-formed to a minimum radius of 3 m that may be useful for barrel vaulting. Ordinary profiled sheets may be curved slightly on site. As a rule of thumb, the depth of the trough in mm gives the maximum curve in metres. Mitred units are available for both internal and external corners with flashings purpose-made to match. Thickness 0.5–1.5 mm. Sheet width 500–1000 mm. Trough depth 20–70 mm for roofing – depths up to 120 mm are normally used for structural decking.

Materials and components 357

Weight 0.9 mm – 3.7 kg/m2. Falls 1.5° (1:40) minimum. Finishes Hot dip galvanising, stove and vitreous enamelling, terne coating, mill finish aluminium, PVC and PVF2 colour coatings, composite bitumen mineral fibres, etc.

Non-metallic profiled sheet roofing and cladding Fibre-cement The most widely used of these materials is fibre-cement, originally incorporating asbestos but now including ‘synthetic and natural fibres’. Long life – 50 years expected with 30-year guarantees ­available – make fibre-cement a viable alternative to profiled metals; suitable for roofing down to 5 degree pitches and for vertical cladding. UK manufactured sheeting is available in 75 mm or 150 mm profiles. Source: www.eternit.co.uk Bituminous fibre Profiled sheets in fibre-reinforced bitumen are relatively short-life but are available with 15-year guarantees; typically used to roof agricultural buildings and small domestic buildings at low cost.

Flat roofs: non-metallic A flat roof is defined as having a fall not greater than 10° (1:6). BS 6229: 2018 Flat roofs with continuously supported coverings deals with design principles.

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Design considerations A flat roof must be structurally rigid, and have substantial and continuous support for the membrane, provision for movement joints, rainwater disposal, thermal design, condensation avoidance, wind resistance, consideration for roof penetrations and appropriate protection of the membrane.

Maintenance It is essential to annually check and clean flat roofs; particularly all outlets at roof level, gutters, weirs, upstands and also bottom outlets of rainwater pipes. In areas of heavy leaf fall, it is prudent to fit brushes in gutters or removable leaf guards on rainwater pipes.

Rainwater Flat roofs should have a minimum fall of 1:80. However, to allow for construction tolerances, a design fall of minimum 1:50 is desirable. The failsafe drainage of flat roofs is to fall to external gutters; less good is via scuppers in parapet walls to external RWPs. Where internal RWPs are planned, position them away from parapet edges where debris will collect and it is difficult to make a watertight seal. Ideally, they should be sited at points of maximum deflection. Avoid only one outlet in a contained roof as this may block, causing water to rise above upstands and cause damage from water penetration or from overloading the structure; ideally provide an overflow in a prominent location to signal blockage of outlets. Where roofs meet walls, upstands must be a minimum of 150 mm high. They should be protected with lead, copper or super purity aluminium flashing tucked 30 mm minimum into the wall.

Materials and components 359

Condensation Condensation is a major cause of failure in bituminous felt roofing, leading to blistering and decay. Moisture-laden rooms below flat roofs should have good ventilation, extra insulation and vapour control layers that can withstand accidental damage during construction. Avoid thermal bridges that can result in localised condensation.

Wind All layers must be properly secured to substrate to resist wind uplift.

Penetration Keep roof penetration to a minimum. Where available, use proprietary components such as flanged roof outlets and sleeves for cables.

Sunlight Ultra-violet light will damage bituminous felt roofs unless mineral surfaced so they should be protected with a layer of stone chippings bonded in hot bitumen or a cold bitumen solution. Alternatively, mineral reinforced cement tiles or glass-­ reinforced concrete tiles laid in a thick coating of hot bitumen will provide a good surface for pedestrian traffic. About 25 mm thick concrete or tiled pavings provide a more stable walking surface and should be bedded on proprietary plastic corner supports that have the advantage of making up irregularities of level and the separation of the promenade surface from the membrane with rapid drainage of surface water. Light-coloured top surfaces and reflective paints reflect the sun’s energy but provide only limited protection against damage from ultra-violet light.

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Vapour control layer Proprietary felts incorporating aluminium foil when laid fully supported are the best type of vapour control layer. They are essential in warm roofs and advisable below cold roofs but are not required in inverted warm roofs. Over profiled metal decking, two layers bonded together may be required because of lack of continuous support.

Mastic asphalt Asphalt is a blend of fine and coarse aggregates bonded with bitumen. The ingredients are heated and blended in batches and either delivered hot in bulk or cast into blocks for re-­ heating on site. Roofing grade asphalts are described in BS 6925: 1988. For ­specification and application of asphalt roofing see BS 8218: 1998. Recent developments include the addition of polymers that claim to make the material more flexible. These are covered by BSEN14023:2010. Asphalt is laid over a separating layer of inodorous black felt to BS 8747: 2007 and BS EN 13707: 2013 and laid in two layers of a combined thickness of 20 mm. Application in two layers allows the joints to be staggered. The final surface is trowelled to produce a bitumen rich layer that is then dressed with fine sand to mask surface crazing in cold weather. This should then be protected with chippings or paving. See ­Sunlight above.

Bituminous membranes Formerly, roofing felts were made of rag, asbestos or glass fibre cores coated with bitumen. More recently, most felts have been made with cores of polyester fleece that give increased stress resistance. See BS 8218: 1998 for specification and application. Newer membranes are often made with polymer-modified bitumen producing greater flexibility and better performance.

Materials and components 361

Roofing felts are applied in two or more layers, bonded in hot bitumen, and bonded by gas torch or by means of a self-adhesive layer incorporated onto one side of the felt. First layer felts, often perforated, bind directly to the substrate. Intermediate felts are smooth faced for full bonding. Top layer felts may have the top surface prepared for site-­ applied protection such as chippings. Cap sheet felts, designed to be left exposed without further protection, incorporate a surface coating of mineral chippings or metal foil.

Single ply membranes Developed in Europe and the US, these are generally available in the UK, for example, EPDM and TPO membranes, see BS ISO 4097: 2014, and are made of plastics, synthetic rubber-based materials and some modified bitumen materials. There are thermoset and thermoplastic type plastics: Thermoset includes all synthetic rubbers. These have fixed molecular structures that cannot be reshaped by heat or solvents and are joined by adhesives. Thermoplastic materials are those whose molecular structure is not permanently set and welds may be formed by heat or solvents. Welding is more satisfactory than gluing but requires greater skill. Sheets may be attached mechanically to the substrate with screw fasteners and disc washers set in seams or by welding membrane to disc washers fixed to substrate, or by adhesive. On inverted warm roofs, the membrane is loose laid and ballasted. The main advantage of single ply membranes is that they are flexible and have a very long life. Some single ply materials may not be used in conjunction with expanded polystyrene insulation.

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Glass Glass used in buildings is composed of silica (sand) 70%, soda 14%, lime 10% and various other oxides. The above ingredients are added to recycled glass and heated in a furnace to around 1550oC, refined, then cooled before floating the molten liquid onto molten tin to form a perfectly flat surface. This is then cooled from 620oC to 250oC in the annealing chamber before the continuous cold glass ribbon is cut into sheets typically measuring up to 6000 × 3210 mm. This material is then used to make a variety of glass sheets with thicknesses from 2 to 25 mm and many different properties and coatings that can be used as follows.

Environmental control Solar control The increased use of glass in architecture today makes it imperative to consider the comfort of a building’s occupants and minimise overheating. Solar control glass can be an attractive feature of a building whilst at the same time reducing the demand on air-conditioning systems, reducing running costs of the building and saving energy. In hot climates, solar control glass can be used to minimise solar heat gain and help control glare. In temperate regions, it can be used to balance solar control with high levels of natural light. Solar control glass can be specified for any situation where excessive solar heat gain is likely to be an issue, from large conservatories to glass walkways and building facades to atria. The Pilkington range of solar control glass offers a range of performance options to suit most building applications: Pilkington Suncool™, Pilkington Optifloat™ tinted and Pilkington Activ SunShade™.

Materials and components 363

All products are available in toughened or laminated form for safety and security requirements and can be combined with other benefits such as noise control. Thermal insulation With increasing environmental awareness, more emphasis is now being placed on ways to save energy in any building, domestic or commercial. In December 2021, the Government published the 2021 editions of the supporting Approved Documents Part L (Conservation of fuel and power) and Part F (Ventilation) of the Building Regulations for new and existing buildings, as well as the new regulation (Part O) addressing the risk of overheating in new homes. More information is available here: https://www.pilkington.com/en-gb/uk/architects/ standards-and-regs/part-l-2021 Glass can play an important role in this. Heat loss is normally measured by the thermal transmittance or U value, usually expressed in W/m2K. In its most basic terms, the lower the U value, the greater the thermal insulation. Insulating glass units incorporating low emissivity glass can significantly improve the thermal insulation values. Pilkington Products Pilkington K Glass™ (on-line low-e): This coating is applied during float glass manufacture and forms the inner pane of a double-glazed unit. Pilkington Optitherm™ S1 Plus: A high-quality clear glass with a specially formulated ‘off-line’ ultra low emissivity coating applied to one surface after glass manufacture and is available in toughened and laminated form. It achieves a Ug value of 1.0 W/ m2K when incorporated in a double-glazed IGU. Pilkington energiKare™: a range of double and triple glazing used to improve the thermal efficiency of homes. It reduces heat loss and allows passive solar gain. U value for air-filled cavity approx. 15% higher. Where cavity width is limited, Krypton filling gives a lower U value than Argon but is not readily available and is more expensive. Warm edge spacer bars, instead of aluminium will also reduce the U value.

Ug value [W/m2K]

0.10 0.16 0.16 0.11 0.40 0.18 0.20 0.26

Transmittance

Outer pane

Reflectance

Direct transmittance

0.31 0.35 0.34 0.32 0.47 0.32 0.34 0.37

Reflectance

Solar radiant heat

0.40 0.34 0.33 0.29 0.29 0.24 0.20 0.16

Absorptance

0.29 0.31 0.33 0.39 0.24 0.44 0.46 0.47

Total transmittance (g value)

0.43 0.37 0.36 0.32 0.32 0.27 0.23 0.19

0.03 0.03 0.03 0.03 0.04 0.03 0.03 0.04

Short wavelength

Long wavelength

Shading coefficients

0.46 0.40 0.38 0.34 0.33 0.28 0.23 0.18

Credit Pilkington United Kingdom Ltd

Pilkington Optifloat TM Clear 4 mm* 0.66 0.25 6 mm 0.65 0.24

0.41 0.39

0.42 0.39

0.17 0.22

0.48 0.47

0.47 0.45

0.08 0.09

Insulating Glass Unit with 6 mm Pilkington OptithermTM S1 plus inner pane and 16 mm 90% argon filled cavity – unless otherwise indicated

Light

Product description

Table 6.2  Optitherm insulating glass

Credit Pilkington United Kingdom Ltd

Pilkington SuncoolTM 6 mm 70/40 0.73 6 mm 70/35 0.70 6 mm 63/33 0.66 6 mm 60/31 0.60 6 mm Silver 60/31 0.50 6 mm 50/25 0.50 6 mm 40/22 0.40 6 mm 30/16 0.29

Insulating Glass Unit with 6 mm Pilkington Optifloat TM Clear inner pane and 16 mm 90% argon filled cavity – unless otherwise indicated

0.55 0.54

Total

1.0 1.0

Argon (90%)

Ug value [W/m2K]

0.49 1.1 0.43 1.0 0.41 1.0 0.37 1.0 0.37 1.0 0.31 1.0 0.26 1.1 0.22 1.0

Transmittance Reflectance Direct Reflectance Absorptance Total transmittance Short Long Total Argon transmittance (g value) wavelength wavelength (90%)

Shading coefficients

Outer pane

Solar radiant heat

Light

Product description

Table 6.1  Suncool solar control glass

66/48 65/47

Descriptive code

73/43 70/37 66/36 60/32 50/32 50/27 40/23 29/19

Descriptive code

364 Architect’s Pocket Book

Materials and components 365

Acoustic Pilkington Optiphon™ is a high-quality acoustic laminated glass that offers excellent noise reduction without compromising on light transmittance or impact performance. The desired acoustic performance can be achieved through combining various thicknesses of glass with a special PVB (polyvinylbutyral) interlayer. Insulating building interiors against noise has now become a major design criterion, due to the rapid increase in road and air traffic and the development of the urban motorways.

Fire A range of fire-resistant glass types is available offering increasing levels of protection, which is measured in defined time periods (30, 60, 90, 120 and 180 minutes) and in terms of Integrity and Insulation or Integrity only as designated by the European Standards. It should be noted that fire-resistant glass must always be specified as part of a tested and approved glazing system, and installation should be carried out by specialists in order to ensure that the expected fire performance is achieved should it be called upon. Areas of glazing are limited by the Building Regulations Part B.

Insulation Pilkington Pyrostop® • Highly successful intumescent technology • Forms opaque and robust insulating barrier against heat, flames and fumes • A sodium silicate interlayer (therefore not liable to flame or smoke on non-fire side)

366 Architect’s Pocket Book

• Classes 30, 60, 90, 120 and 180 minutes insulation & integrity (EI) [2] • Impact safety up to class 1(B)1 [1] • Extensively specified worldwide in timber and metal framing systems • Good visual and optical quality

Integrity Pilkington Pyrodur® • Based on intumescent technology • Class 30 and 60 mins integrity (E) [2] • Protection from radiant heat (EW30) and added insurance of insulation for 15 minutes (EI) [2] • Impact safety class up to 1(B)1 [1] Pilkington Pyrodur® Plus • A unique and special intumescent technology • Only 7 mm thick, integrity 30 minutes (E) [2] • Protection from radiant heat (EW30) and added insurance of insulation for 15 minutes (EI) [2] • Ideal for internal applications in partitions, doors and door set glazed screens • 2(B)2 impact safety class [1] • Insulating glazing units also available Pilkington Pyroclear® • A unique, NEW, special modified toughened glass, 30 and 60 minutes integrity (E) [2] • Designed for consistency: proprietary NSG processing technology, a special toughening specification and specific control criteria • Product design and use backed by a new validated computer model

Materials and components 367

• Achieved 50 successive tests in timber frames before launch • Less sensitive to edge cover relative to standard modified toughened glasses • Impact safety 1(C)1, i.e. at highest drop height in the impact test [1] • Large sizes and flexible use in timber, metal and screens • Ideal for safe escape before fire conditions become untenable 1 BS EN 12600, Impact test and classification. Class C indicates mode of breakage as toughened safety glass. Class B indicates mode of breakage as toughened laminated glass. 2 BS EN 13501-2, Classification from fire resistance tests. I = Insulation; E = Integrity; W = radiation (not in UK regulations) Source: www.pilkington.co.uk/fire

Safety and security From security to fire resistance, safety glass can be used to protect a building’s occupants in many ways, while also allowing the creation of bold and attractive designs. The main categories in which glass can be used for protection are outlined here. Safety glass Requirement K5 of the Building Regulations concerns glazing in critical locations. In such places, glass should either (1) break safely, (2) resist impact without breaking, or (3) be shielded or permanently protected from impact. Glass that is deemed to break safely must conform to BS 6262: 2005. Manifestations may need to be incorporated in the

368 Architect’s Pocket Book

glazing or applied afterwards to satisfy the Buildings Regulations Part K. Toughened and laminated glass can meet these requirements. Toughened glass Toughened glass is normal annealed glass (see Pilkington brochures) subjected to heating and rapid cooling. This produces high compression in the surface and compensating tension in the core. It is about four to five times stronger than annealed glass and is highly resistant to thermal shock. When it breaks, it shatters into relatively harmless pieces. It cannot be cut, drilled or edgeworked after toughening. Any such work must be done prior to toughening. The ‘strain’ pattern of toughening, i.e. horizontal bands about 275 mm apart, may be noticed in bright sunlight and is called anisotropy. https://www.pilkington.com/en-gb/uk/architects/ask-­pilkington? question={4CEE91A0-A0CD-4E5E-9A4E-3F2257B4740A} Laminated glass Laminated glass is made from two or more panes of various glasses with interlayers of PVB bonded between each pane. Normal thickness is 3 ply, i.e. two panes of glass and one interlayer. On impact, the glass adheres to interlayers. Unlike toughened glass, it can be cut, drilled and edge worked after manufacture. Screen-printed designs can be incorporated during manufacture. Pilkington Optilam™ is produced by combining two or more sheets of glass with PVB interlayers, and it is this lamination that enables it to offer impact protection and safety. By varying the number of layers and thickness of the glass, it can offer wide-ranging benefits and be used in various applications. Glass is categorised into safety and security. Safety is where protection is needed from accidental damage and security for

Materials and components 369

wilful damage. Glass used for security reasons can be further broken down into the types of threat: • Manual attack • Ballistic attack • Explosion resistance: See separate section Glazing resistant to manual attack glasses have thicker interlayers and are designed to resist manual attack.to BS EN 356: 2000: ‘Glass in building – Security glazing – Testing and classification of resistance against manual attack’ Bullet-resistant glasses are made from thicknesses from 20 mm up. They are designed to meet specific bullets from 9 mm automatics up to 5.56 mm military rifles or solid slug shotguns. They can also provide protection against bomb blast. Glass beams, posts and balustrades can be formed from laminated sheets.

Glazing system Pilkington Profilit™ is a U-shaped profiled glass. It is translucent, but not transparent, with or without a patterned surface on the outside and has the quality features of cast glass. This highly durable product allows light to enter buildings whilst presenting a translucent external appearance. The glass is available in a variety of colours and textures with varying translucency, allowing for the passage of natural light without the loss of privacy.

Self-cleaning Pilkington Activ™ is the first dual-action “self-cleaning glass”. Firstly, it breaks down any ‘organic’ dirt deposits, such as the organic content of bird droppings and tree sap, and secondly,

370 Architect’s Pocket Book

rainwater ‘sheets’ down the glass to wash the loosened dirt away. This helps to keep the glass free from dirt, giving not only the practical benefit of less cleaning, but also clearer, better-looking windows. The Pilkington Activ™ Range in­ cludes products that benefit from both self-cleaning and solar control properties helping to create an environment that can be used all year round.

Low-Iron Glass Low-iron glass is made using carefully selected raw materials with a naturally low iron content. Pilkington Optiwhite™ is a low-iron extra clear float glass with very high light transmission. It is practically colourless, and the green cast inherent to other glasses is not present. It is therefore ideal for use where glass edges are visible or where a neutral colour is desired. As its light transmission is higher than clear float glass, it is perfect for applications where transparency and purity of colour are desired.

Decorative A variety of textured, satin, reflective, etched, screen-printed, coloured, stained and handmade glasses are available. Source: w ww.pilkington.co.uk https://www.pilkington.com/en-gb/uk/architects Pilkington Glass Range Brochure Pilkington UK Glass Range Data Sheet

Materials and components 371

Glass blocks Glass blocks are now no longer made in the UK but are imported from Germany and Italy. Metric and imperial sizes are made, imperial being used not only for new work but also for renovation and the US market. Metric sizes

115 × 115 × 80 mm; 190 × 190 × 80 and 100 mm; 240 × 240 × 80 mm; 240 × 115 × 80 mm; 300 v 300 × 100 mm

Imperial sizes

6″ × 6″ × 31/8″ and 4″; 8″ × 8″ × 31/8″ and 4″; 8″ × 4″ × 31/8″ and 4″; 8″ × 6″ × 31/8″

Colours

Clear (transparent) as standard; bronze, azure, cobalt, blue, turquoise, pink, green, grey

Patterns

Waves, chequers, ribs, sand blasted, Flemish, frosted, bubble etc.

Specials

Fixed louvre ventilator (190 mm sq), corner blocks, bullet-resistant, end blocks with one side mitred for unframed edges to freestanding panels

Radii

Minimum internal radii for curved walls for block widths as follows: 115 mm = 650 mm; 6″ (146 mm) = 1200 mm; 190 mm = 1800 mm; 240 mm = 3700 mm

Weight

80 mm thick = 100 kg/m2; 100 mm thick = 125 kg/m2

U-values

80 mm thick = 2.9 W/m2K; 100 mm thick = 2.5 W/m2K

Light transmission

Clear blocks = 80%; bronze = 60% approx

Fire rating

Class O: fixing systems for both half-hour and one-hour fire rating integrity and thermal insulation

372 Architect’s Pocket Book

Sound insulation

48–52 db subject to frequency

Structure

Glass blocks are self-supporting but not load-bearing Mortar jointed panels should not exceed 5 m long × 3.5 m high (3 m for fire-resisting panels) in any direction, nor be greater than 17.5 m2

Fixing

Glass blocks are generally fixed on site using the traditional Rods and Mortar technique but can be prefabricated in panels. The normal joint is 10 mm but can be up to 22 mm max wider to suit dimensional requirements Blocks are laid in wet mortar with 6 or 8 mm Ø SS reinforcing bars fixed horizontally or vertically, normally about every other block. Joints are then pointed up Silicone sealants are applied at perimeters Intumescent mastics are applied to internal and external perimeter joints for fireresisting panels There is also the ‘Easifix’ dry fix system using plastic profiles to space and centre the blocks and a special adhesive to bond the system together; 5 mm joints are grouted and perimeter joints filled with a silicone seal

Pavement lights 100 × 100 square, up to 198 × 198, 117 dia., can be supplied separately for site casting or precast in concrete ribs for foot or vehicular traffic Colours

Clear, sandblasted, blue, amber

Source: www.luxcrete.co.uk www.glassblocks.co.uk

Materials and components 373

Timber Timber sustainability The world’s forests are under threat from illegal logging, clearance for agricultural expansion and poor management. However, timber can be the most energy-efficient material. A tree grows to maturity in the space of one human lifetime, whereas stocks of oil, fossil fuels and minerals take millennia to produce and are therefore not renewable resources. The growth of trees fixes carbon and actually reduces the amount of CO2 in the atmosphere. This advantage is only realised in well-­managed forests where trees are replaced. Timber has seven times less embodied energy (by weight) than that of steel and 29 times less than aluminium, as it needs no heat for manufacture and extraction is relatively cheap compared with mining. How do architects obtain information from suppliers as to whether timber comes from renewable resources? The Forest Stewardship Council (FSC) was founded in 1993 and is an international non-profit and non-governmental organisation. It is an association of environmental and social groups, timber trade organisations and forestry professionals from around the world. Its objectives are to provide independent certifiers of forest products and to provide consumers with reliable information about these materials. It evaluates, accredits and monitors timber all round the world, whether it is tropical, temperate or boreal (northern). Certification is the process of inspecting forests to check they are being managed according to an agreed set of principles and criteria. These include recognition of indigenous people’s rights, longterm economic viability, protection of biodiversity, conservation of ancient natural woodland, responsible management and regular monitoring. Timber from FSC-endorsed forests will be covered by a ‘chain-of-custody-certificate’. Consult the FSC for their lists of suppliers and certified timber and wood products.

374 Architect’s Pocket Book

Regulation (EU) No 995/2010 of the European Parliament: The European Union Timber Regulation (EUTR) puts obligations on businesses that trade in timber and timber-related products. It applies to timber originating in the domestic (EU) market, as well as from third (non-EU) countries. Due diligence systems are in place to minimise the possibility that products placed on the EU market contain illegally harvested timber. They provide information on the supply of timber products. The core of the ‘due diligence’ notion is that operators undertake a risk management exercise so as to minimise the risk of placing illegally harvested timber, or timber products containing illegally harvested timber, on the EU market. The three key elements of the “due diligence system” are: Information: The operator must have access to information describing the timber and timber products, country of harvest, species, quantity, details of the supplier and information on compliance with national legislation. Risk assessment: The operator should assess the risk of illegal timber in his supply chain, based on the information identified above and taking into account criteria set out in the regulation. Risk mitigation: When the assessment shows that there is a risk of illegal timber in the supply chain that risk can be mitigated by requiring additional information and verification from the supplier. Sources: Forest Stewardship Council; www.fsc.org Friends of the Earth www.friendsoftheearth.uk

Timber nomenclature ‘Softwood’ and ‘hardwood’ are botanical terms and do not­ ­necessarily reflect the density of the species. Softwood comprises coniferous (cone-bearing) trees of northern climates and are ­relatively soft with the exception of Pitch Pine and Yew (670 kg/m3). Hardwood comprises deciduous trees and vary

Materials and components 375

enormously in density from Balsa (110 kg/m3) to Lignum Vitae (1250 kg/m3).

Moisture Moisture content of newly felled trees can be 60% and higher. Air drying will reduce the moisture content to approximately 18%. Further kiln drying can reduce the moisture content to 6%. Recommended average moisture content for timbers from BS EN 942: 2007 External joinery Internal joinery Buildings with intermittent heating Buildings with continuous heating from 12°C to 16°C Buildings with continuous heating from 20°C to 24°C

16° 15° 12° 10°

Durability This relates to fungal decay. It is expressed in the five durability classes described below and numbered in the tables on pp. 280–281 and 282–284. Sapwood of all species is non-durable and should not be used in exposed situations without preservative treatment. 1 = Very durable 2 = Durable 3 = Moderately durable 4 = Slightly durable 5 = Non-durable

more than 25 years 15–25 years 10–15 years 5–10 years less than 5 years

BS EN 350.

Classes of timber for joinery These are effectively appearance classes and make no reference to durability and workability, stability or surface absorbency. The four classes characterise the quality of timber and moisture content after machining, at the time it is supplied to the first

376 Architect’s Pocket Book

purchaser. They describe the presence (or absence) of knots, splits, resin pockets, sapwood, wane, straightness of grain, exposed pith, rot, joints (in long timbers), plugs or filler (of knots). Class CSH

Clear softwood and hardwood, i.e. free from knots or other surface defects. Difficult to obtain in softwood with the possible exception of selected Douglas fir, hemlock, parana pine and western red cedar Class 1 This is suitable for both softwood and hardwood components, particularly small mouldings such as glazing bars and beads and for joinery that will receive a clear finish Class 2 Suitable for general purpose softwood joinery and laminated timber. Commonly used for window casements Class 3 As class 2 but with greater latitude in knot size and spacing

Classes of timber for cladding BS 1186-3: 1990 • There are three grades applicable to external timber cladding, mostly concerned about the size and frequency of knots: °° Class 1: Is suitable for ‘high status’ buildings. Using cladding boards of 100–150 mm width, sound knots are limited to 22.5 mm. Most hardwoods are available to this quality, but in softwood, it is limited to imported douglas fir and western red cedar. °° Class 2: Is the most common classification for unfinished timber cladding. Sound knots are limited to 35 mm. °° Class 3: Is generally the traditional class for painted cladding. Knots are restricted to 50 mm or no more than the 35% of the board width. There is also available a Class CSH, though this is more relevant to small profiled trims since it effectively prohibits knots.

Timber sizes Softwood and hardwood are usually available in sizes as shown in the tables on p. 377 and p. 383.

Materials and components 377

European softwood is generally supplied in 1.8 m lengths in increments of 300 mm up to about 5.7 m. North American softwood is normally supplied in 1.8 m lengths up to 7.2 m in 600 mm increments. Other lengths can be supplied to special order up to a maximum of 12.0 m. Hardwood which is imported in log form may be cut to specified sizes and is available in 19, 25, 32, 38, 50, 63 and 75 mm thicknesses; widths from 150 mm up and lengths from 1.8 m to typically 4.5 m and sometimes 6 m.

Softwood: standard sawn sizes (mm) Thickness 25 38 50 75 100 125 150 175 200 225 250 300 12 16 19 22 25 32 36 38 44 47 50 63 75

•

•

•

•

• • •

•

•

• • •

100 150 200 250 300

• * * * * * * • * * * •

• * * * * * * * * * * * * *

* * * * * * * * * * * *

• * * * * * * * * * * * * * *

* *

* *

* *

* *

* *

* * * * * *

* * * * * *

* * * * * *

* * * *

* * *

*

*

*

* *

* * *

* *

These sizes generally from Europe

These sizes generally from North America

•: sizes that may be available from stock or sawn from larger standard sizes. *: sizes laid down in BS EN 1313-1: 2010.

Reduction from sawn sizes by planing Structural timber Joinery and cabinet work

3 mm up to 5 mm over 7 mm up to 9 mm over 11 mm up to 13 mm over

100 mm 100 mm 35 mm 35 mm 150 mm 150 mm

378 Architect’s Pocket Book

Softwood Species

Place of origin

Appearance

Density (kg/m3)

Durability class

Veneer

Uses (remarks)

Cedar of Lebanon* Cedrus Libani

Europe UK

Light brown

580

2



Garden furniture, drawer linings (aromatic smell)

Douglas Fir Pseudotsuga menziesii

North America UK

Light, reddish Brown

530

3



Plywood, construction (long lengths), joinery, vats

Hemlock, western Tsuga heterophylla

North America

Pale brown

500

4

Larch, European Larix decidua

Europe

Pale, reddish

590

3

Larch, Japanese Larix kaempferi

Europe

Reddish brown

560

3

Parana Pine Araucaria angustifolia

South America

Golden brown and red streaks

550

4

Pine, Corsican Pinus nigra maritima

Europe

Light 510 yellow-brown

4

Joinery, construction

Pine, maritime Pinus pinaster

Europe

Pale brown to yellow

510

3

Pallets, packaging

Pine, pitch Pinus palustris

South USA

Yellowbrown to red-brown

670

3

Heavy construction, joinery

Pine, radiata Pinus radiata

South Africa Australia

Yellow to pale brown

480

4

Packaging, furniture

Pine, Scots Pinus sylvestris

UK

Pale yellowbrown to red-brown

510

4

Construction, joinery

Construction (large sizes), joinery (uniform colour) 

Boat planking, pit props, transmission poles Stakes, construction



Interior joinery, Plywood (may distort)

Materials and components 379

Species

Place of origin

Appearance

Density (kg/m3)

Durability class

Pine, yellow Pinus strobus

North America

Pale yellow to light brown

420

4

Pattern-making, doors, drawing boards

Spruce Canadian Picea spp Species

Canada

White to pale yellow

450

4

Construction, joinery

Spruce, sitka Picea sitchensis

UK

Pinkish brown

450

4

Construction, pallets, packaging

Spruce, western white Picea glauca

North America

White to pale 450 yellow-brown

4

Construction (large sizes), joinery

Western Red Cedar Thuja plicata

North America

Reddish brown

390

2



Exterior cladding, shingles, greenhouses, beehives

Whitewood, European Picea abies and Abies alba

Europe Scandina via USSR

White to pale 470 yellow-brown

4



Interior joinery, construction, flooring

Yew Taxus baccata

Europe

Orangebrown to purple-brown

670

2



Furniture, cabinetry, turnery (good colour range)

Veneer

Uses (remarks)

Source: Timber Research and Development Association www.trada.co.uk * = limited availability.

380 Architect’s Pocket Book

Hardwood Species

Place of origin

Appearance

Density (kg/m3)

Durability class

Veneer

Uses (remarks)

Afrormosia Pericopsis elata

West Africa

Light brown, colour variable

710

1



Joinery, furniture, cladding

Agba Gossweilero dendron balsamiferum

West Africa

Yellowbrown

510

2



Joinery, trim, cladding (may exude gum)

Ash, European Fraximus exelsior

UK Europe

Pale white to light brown

710

5



Interior joinery (may be bent), sports goods

Balsa* Ochroma pyramidale

South America

Pinky-white

160

5

Beech, European Fagus sylvatica

UK Europe

Pale pinkish brown

720

5



Furniture (bends well), flooring, plywood

Birch, European* Betula pubescens

Europe Scandinavia

White to light brown

670

5



Plywood, furniture, turnery (bends well)

Cherry, European* Prunus avium

Europe

Pink-brown

630

3



Cabinet making (may warp), furniture

Chestnut, sweet* Castanea sativa

Europe

Honeybrown

560

2



Joinery, fencing (straight grained)

Ebony* Diospyros spp

West Africa India

Black with grey stripes

1110

1



Decorative work, inlaying, turnery (small sizes only)

Elm, European* Ulmus spp

Europe UK

Reddish brown

560

4



Furniture, coffins, boats (resists splitting)

Gaboon* Aucoumea klaineana

West Africa

Pink-brown

430

4



Plywood, blockboard

Greenheart Ocotea rodiaei

Guyana

Yellow-olive green to brown

1040

1

Insulation, buoyancy aids, architectural models

Heavy marine construction, bridges etc. (very large sizes)

Materials and components 381

Species

Place of origin

Appearance

Density (kg/m3)

Durability class

Hickory* Carya spp

North America

Brown to red-brown

830

4

Iroko Chlorophora excelsa

West Africa

Yellowbrown

660

1

Keruing Dipterocarpus spp

SE Asia

Pink-brown to dark brown

740

3

Heavy and general construction, decking, vehicle flooring

Lignum Vitae* Guaicum spp

Central America

Dark greenbrown

1250

1

Bushes, bearings, sports goods (small sizes only)

Lime, European* Tilia spp

UK Europe

Yellowwhite to pale brown

560

5

Carving, turnery, bungs, clogs (fine texture)

Mahogany, African Khaya spp

West Africa

Reddish brown

530

3



Furniture, cabinetry, joinery

Mahogany, American Swietenia macrophylla

Brazil

Reddish brown

560

2



Furniture, cabinetry, boats, joinery (stable, easily worked)

Maple, rock Acer saccharum

North America

Creamywhite

740

4



Flooring, furniture, turnery (hard-wearing)

Meranti, dark red Shorea spp

SE Asia

Medium to dark red-brown

710

3



Joinery, plywood (uniform grain)

Oak, American red Quercus spp

North America

Yellowbrown with red tinge

790

4



Furniture, interior joinery (bends well)

Oak, European Quercus robur

UK Europe

Yellow to warm brown

690

2



Construction, joinery, flooring, cooperage, fencing (bends well)

Veneer

Uses (remarks)

Tool handles, ladder rungs, sports goods (bends well) 

Joinery, worktops, construction

382 Architect’s Pocket Book

Hardwood – continued Species

Place of origin

Appearance

Density (kg/m3)

Durability class

Veneer

Uses (remarks)

Obeche Triplochiton scleroxylon

West Africa

White to pale yellow

390

4



Interior joinery, furniture, plywood (very stable)

Plane, European* Platanus hybrida

Europe

Mottled red-brown

640

5



Decorative work, turnery, inlays

Ramin Gonystylus spp

SE Asia

White to pale yellow

670

4



Mouldings, furniture, louvre doors (easily machined)

Rosewood* Dalbergia spp

South America India

Purplishbrown with black streaks

870

1



Interior joinery, cabinetry, turnery, veneers

Sapele Entandophragma cylindricum

West Africa

Red-brown with stripe figure

640

3



Interior joinery, door veneers, flooring

Sycamore* Acer pseudoplatanus

Europe UK

White to creamy yellow

630

5



Furniture, panelling, kitchen ware (does not taint or stain)

Teak Tectona grandis

Burma Thailand

Golden brown

660

1



Furniture, joinery, boats (chemical- and termite-resistant)

Utile Entandophragma utile

West Africa

Reddish brown

660

2



Joinery, furniture, cabinetry

Walnut, European* Juglans regia

Europe UK

Grey-brown With dark streaks

670

3



Furniture, turnery, gun stocks (decorative)

* = limited availability.

Materials and components 383

Hardwood: standard sawn sizes (mm) Thickness

50

63

75

200

225

250

300

*

*

*

*

*

*

*

*

*

*

*

*

32

*

*

*

*

*

*

*

*

*

*

*

*

38

*

*

*

*

*

*

*

*

*

*

*

*

*

*

*

*

*

*

63

*

*

*

*

*

*

75

*

*

*

*

*

*

100

*

*

*

*

*

*

19 25

50

100

125

150

175

* = sizes laid down in BS EN 1313-2: 1999.

Reduction from sawn sizes by planing Structural timber Flooring, matchings Wood trim

Joinery and cabinet work

3 mm up to 5 mm for 6 mm for 5 mm up to 6 mm for 7 mm for 6 mm up to 7 mm for 8 mm for 9 mm for 10 mm for 7 mm up to 9 mm for 10 mm for 12 mm for 14 mm for

100 mm 101–150 mm 151–300 mm 25 mm 26–50 mm 51–300 mm 25 mm 26–50 mm 51–100 mm 101–105 mm 151–300 mm 25 mm 26–50 mm 51–100 mm 101–150 mm 151–300 mm

384 Architect’s Pocket Book

Softwood mouldings

Materials and components 385

Hardwood mouldings

386 Architect’s Pocket Book

Source: James Latham plc www.lathamtimber.co.uk

Materials and components 387

Building boards Chipboard Particle board with a variety of woodchips bonded with resin adhesives. No chipboard is completely moisture-resistant and should not be used externally. Seven types identified in BS EN 312: 2010 The following seven types of boards are distinguished as follows: 1: boards for general use, for dry applications P P 2: boards for interior decoration (including furniture), for dry applications P 3: boards for non-load-bearing purposes, to be used in wet room areas P 4: boards for load-bearing purposes, for dry applications P 5: boards for load-bearing purposes, to be used in wet room areas P 6: boards with high load capacity, for load-bearing purposes, to be used for dry applications P 7: boards with high load capacity, for load-bearing purposes, to be used in wet room areas Relevant requirements and characteristics of the different board types can be found in the EN 312:2010. Sheets can be supplied wood veneer and melamine-faced; with low formaldehyde rating Thicknesses Sheet sizes

12, 15, 18, 22, mm. 1220 × 2440 mm, 1220 × 2745 mm, 1220 × 3050 mm, also 600 × 1220, 1829, 2440 mm for 18 and 22 mm flooring

Wood veneer and melamine-faced shelves Thickness 15 mm Widths 152 (6″), 229 (9″), 305 (12″), 381 (15″), 457 (18″), 533 (21″), 610 (24″), 686 (27″), 762 (30″); 914 mm (36″) Lengths 1830 (6′), 2440 and 2800 mm (8′)

388 Architect’s Pocket Book

Blockboard Composite board with one or two veneers applied to solid core of timber blocks 7–30 mm wide, also available with decorative wood or laminate veneers, commonly 18 mm thick. Thicknesses Sheet sizes

13, 16, 18, 22, 25, 32, 38 and 45 mm 1220 × 2440 mm; 1525 × 3050 and 3660 mm; 1830 × 5200 mm

Laminboard A composite board with veneers applied to a core of narrow timber strips (as opposed to wider blocks in blockboard). It is heavier, flatter and more expensive than blockboard but is less likely to warp. Thicknesses Sheet sizes

13, 16, 19, 22, 25, 32, 38 and 44 mm 1220 × 2440 mm, 1525 × 3050 and 3660 mm.

Engineered floorboards Engineered wood flooring is timber which consists of more than one layer. By placing each layer so that the grain runs at 90° it becomes virtually impossible for the wood to swell or shrink with changes in humidity and so dramatically increases its stability. The top layer of an engineered board (the lamella) is solid wood, usually hardwood, and may be anything from 2 to 6 mm thick; obviously the thicker the surface layer the more times it can be sanded and refinished to remove the ravages of wear; the thickest wear layers are equivalent to those on solid timber boards. The lamella is securely bonded to one or two further layers – this may be a multi-layered plywood or a sandwich with either a softwood or hardwood core. Engineered boards should not be confused with laminate or veneer. Laminate uses an image of wood on its surface whilst veneer uses only a very thin layer of wood over a core of some type of composite wood product, usually fibreboard.

Materials and components 389

Engineered timber is now the most common type of wood flooring used globally. Not only are they more stable than solid planks but they also offer alternative, easier methods of installation. Furthermore the technology has enabled the production of much wider boards as well as the application of an enormous variety of really interesting finishes, reducing the demand for exotic species since their rich colours can now be simulated with the use of oils, heat and pressure. Source: Havwoods; www.havwoods.com

SIPS Panels Structural Insulated Panels (SIPs) are a structural frame made from a sandwich of two layers of structure and one layer of insulation. A typical 144 mm sips panel comprises of two layers of oriented strand board (OSB), either side of 122 mm of premium carbon treated expanded polystyrene (EPS). The nature of the stressed skin panel makes it exceptionally strong, whilst largely comprising of insulation, meaning you can achieve high levels of insulation in thinner wall thicknesses than other forms of construction. With no need for cavity or internal insulation, structural insulated panels can provide a very fast way of constructing very efficient walls with U-values as low as 0.14 i.e. to Passivhaus standards. SIPs can be used as the inner skin of an external wall (in place of timber frame or blocks), or can be used as a pre-insulated roofing structure. They are suitable for new builds and home extensions as well as being ideal infill panels between other structures like steel or oak frames. Structural insulated panels can be used with any external cladding, be it brick, render, weatherboarding or metal cladding. Equally they can be roofed with slates, tiles or metal roofing. Internally they can be simply finished with plasterboard and a skim coating (with service cavities where needed) meaning that wet trades are kept to a minimum, speeding up build times even further.

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SIPs have a long history, having been first developed in America in the 1930s and have been used in the UK since the 1980s. They have a strong track record of testing, with most manufacturers members of the Structural Timber Association (STA). The BRE (Building Research Establishment) has written an Information Paper (IP 13/04) on structural insulated panels and have conducted testing on SIPs on behalf of the Government and insurers. Source: Sips Eco Panels www.sipsecopanels.co.uk

Glulam beams Glulam (laminated beams) is a more natural alternative to steel or concrete. By the turn of the last century, German structural design engineer Otto Hetzer presented a patent described as ‘a bent structural component of timber for building applications,’ which later became known as glulam. Glulam is made by gluing together, under pressure and heat, laminates of timber that have been accurately planed. The resulting product is strong, stable, and corrosion proof with significant advantages over structural steel and concrete. Glulam is made with wood from Scandinavian sustainable forests. The trees used are usually spruce, though can sometimes be redwood or Siberian larch. The manufacture, distribution, and treatment of glulam, all consume less energy than other structural building materials. Glulam is a long-lasting material that’s easy to work with. Versatile: Glulam can be used for almost any type of structure. Light: Glulam is one-sixth the weight of an equivalent reinforced concrete beam (two-thirds the weight of steel). Glulam’s lower weight leads to savings in transport, foundations, and building. Easy fixing: Material that’s easy to handle, work, and erect.

Materials and components 391

Flexible to your specifications: To your specific needs, with standard sizes. Fire-resistant in comparison to steel: An important safety factor. Durable: Glulam is durable with standard coating or preservative, but extra durability can be provided with special ­pressure-impregnated preservative, too. Appearance: Glulam has a natural and attractive appearance. Approved British Standard: 4169:1988 and BS EN 386:1995 ‘Specification for Glued Laminated Timber Structural Members’. Energy conserving: Timber is a renewable resource that’s ecologically attractive and glulam uses only a tenth of the energy it would take to produce an equivalent steel beam. Source: Glulam Ltd www.glulambeams.co.uk

Hardboard Available in a range of grades to BS EN 622-2:2004 Thin, dense boards with one very smooth face and mesh textured reverse. Grainless, knotless, and will not easily split or splinter. It can be bent, is easy to machine, has high internal bond strength for gluing and good dimensional stability. Two types available: Standard hardboard Oil tempered hardboard Thicknesses Sheet sizes

= general internal linings and door facings = structural purposes (higher strength and moisture resistance), flooring overlays 3, 4.8 and 6.0 mm 600 × 1220, 1220 × 2440 mm

Also available: Perforated hardboard with 4.8 mm Ø holes @ 19 mm centres × 3.2 mm thick and 7.0 mm Ø holes @ 25 mm centres × 6.0 mm thick Hardboard with painted finishes.

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Medium Density Fibreboard (MDF) Range of grades to BS EN 622–5: 2009 Homogeneous board of softwood fibres bonded with synthetic resins producing a very dense, fine textured uniform material which can be machined to great accuracy. Normal grades are not moisture-resistant but moisture-resistant grades are available. Low and zero formaldehyde (Medite, etc.), flame-retardant and integrally coloured boards are also available. Thicknesses 6, 9, 12, 15, 18, 22, 25 and 30 mm (smaller and larger thicknesses also made by a few manufacturers). Sheet sizes 1220 × 2440 mm 1525 × 2440 mm 1830 × 2440 mm 1220 × 2745 mm 1525 × 2745 mm 1830 × 3660 mm 1220 × 3050 mm 1525 × 3050 mm

Mediumboard Range of grades to BS EN 622–3: 2004 A board with a density between that of wood fibre insulation board and standard hardboard. It has good thermal and insulation properties with a fine finish. Can be cold and steam bent. Moisture-resistant and flame-retardant grades available. Used for notice boards, ceilings, wall linings, shop fittings, display work and pin boards. Thicknesses Sheet size

6.4, 9.5 and 12.7 mm 1220 × 2440 mm

Source: Sundeala; www.sundeala.co.uk

Oriented Strand Board Made from softwood strands, approximately 75 mm long, placed in layers in different directions, bonded and compressed

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together with exterior grade water-resistant resins. A ‘green’ product (zero formaldehyde) made from thinnings from managed plantations. Process utilises 95% of the wood, discarded bark being used for fuel or horticulture. Cheaper than plywood, strong in both directions, with a uniform and decorative appearance. OSB3 can be plain edged or T&G on two or four sides. Thicknesses Sheet sizes

9, 11, 15, 18, 22 mm 1200 × 2400 mm; 1220 ×2440 mm; 1200 × 2700 590 × 2400 mm and 2440 mm for 18 and 22 mm thick t & g flooring

Source: West Fraser www.uk.westfraser.com

Timber cladding Timber boards are tongued and grooved on opposite sides. Many species are used for external cladding, both hardwood such as European Oak and softwood such as European Larch, Siberian Larch and Douglas Fir. Thermowood is produced by treating softwood in special chamber kilns at high temperatures. It is more stable than softwood and resistant to moisture or decay. Joints can be plain butt joints, fixed with gaps or moulded with ‘V’ or quirk (rounded) shoulders for wall cladding. External timber cladding durability is enhanced by rainscreen detailing to allow airflow around the boards, with the wall behind the cladding typically relying on a vapour-permeable membrane as protected weatherproofing. Timber may be left untreated to weather naturally, stained on site or pre-treated to control weathering or add fire retardance.

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Typical sizes of cladding Nominal size (mm) Laid width (mm) 12.5 × 100 19 × 75 19 × 100 19 × 150 25 × 75 25 × 100 25 × 150

 80  55  80 130  55  80 130

Finished thickness (mm) 10 15 15 15 20 20 20

Composite decking and cladding These boards are made from recycled woods and plastics. They are produced in several colours and widths with wood grain or grooved surfaces and unlike timber will not rot. This means durable, low maintenance, non-slip, anti-splinter, long-lasting decking providing up to 25 years limited residential warranty. Decking can be laid on traditional timber or plastic joists, or adjustable pedestals. Typical sizes are: Board cross section: 21 × 145, 22 × 143 mm; Length: 2.2 m or 4 m; Spans: 300–400 mm. Accessories such as fascia boards are generally available. Cladding is also produced in several colours and profiles and can be laid horizontally or vertically to provide a decorative rainscreen. Smaller profiles can also be useful in weather vulnerable and inaccessible situations for long life, such as dormer fascias and trims with 15-year residential warranty or 10-year commercial warranty. Board size: 21 × 150 × 4000. Source: www.envirobuild.com

Materials and components 395

Plywood Made from softwood and hardwood veneers placed at right angles, or sometimes 45°, to one another. The veneers are strong in the direction of the grain, weak in the other. Thus structural plywoods have odd numbers of layers so that the grain to the outside faces lies in the same direction. Adhesives used are described as WBP (weather- and boil-proof) for external or arduous conditions. BR (boil-resistant), MR (moisture-resistant) and INT (interior) are progressively less resistant. Since many hardwood plywoods are sourced from unstainable forestry, it is advisable to specify softwood ply in preference. Plywoods are graded according to species and country of origin and are effectively as follows: Exterior bonded: BS EN 314-2 – Class 3 Thicknesses from 3 mm to 30 mm (up to 50 mm on request) Sizes 1220 mm × 2440 mm / 3050 mm plus 1525 × 3050 mm / 3660 mm, cross grain 2440 mm × 1220 mm long grain panels always available and larger non-standard panels can be made to order up to 12,500 mm long. Grades B/BB, S/BB and S+/BB The highest grades generally stocked BB, BB/WG or BB/CP. The main commercial grades for general purpose applications are WG, CP and C. The lower grades in which face quality is not important are used for packing, crates and pallets. Exterior bonded: BS EN 314-2:1993 – Class 1/2 Thicknesses from 3 mm to 24 mm Sizes and falling sizes 1525 × 1525 mm and falling sizes BB, C and WG Grades

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Thin Finnish Birch Plywood Thicknesses from 0.4 mm up to 3 mm in stock Sizes 1220 × 1220, 1270 × 1270, 1525 × 152 5mm, 1200 × 2400 mm Grades BR/BR or IV/IV, III/III, II/II or I/I Source: James Latham plc www.lathamtimber.co.uk

Impregnated fibreboards Typically bitumen-impregnated wood fibre used for external, vapour-permeable but weather-resistant sheathing to timber and steel framing, as well as for expansion joint filler strips in concrete and masonry. Typical sizes comprise 1200 × 2400 in 6 mm, 9 mm and 12 mm thicknesses. Fibreboard sheathing without bitumen also available with greater permeability but less weather resistance. BS EN 13171: 2012 + A1: 2015

Insulating fibre boards Low-density wood fibre boards for internal and external ­vapour-permeable insulation to framed and masonry buildings are available with rebated or tongued and grooved joints, typically in thicknesses from 20 to 140 mm.

Strawboards Low-density, permeable boards are used for roofing, ceilings, partitioning, door cores, etc.; these boards are fire-resistant as well as acoustically and thermally insulating; thickness is 50 mm and above; sizes are of 1200 × 2400 and are made to order.

Materials and components 397

Flaxboards Particle boards are made of compressed flax shive (70%), sawdust and resin, typically lighter than chipboards; they are used for similar purposes such as door cores, panelling, furniture and worktops and are available in larger sizes up to 6 m in length × 1200 widths, and from 12 to 60 mm thick.

Clayboard Clayboard® has a 100% recycled honeycomb core, which is set between lightweight polypropylene facings to create a technically sound void to effectively protect a structure from clay heave damage as a result of ground movement. Board size: 2440 × 1000 mm Thicknesses: 60, 85, 110, 160 mm Source: www.dufaylite.com Celenit building/wood wool boards – An alternative to plasterboards Wood wool boards have been used in buildings for decades and are very popular as a lime carrier. These strands of wood, bound together with a small proportion of Portland cement, provide an excellent background for lime plasters, eliminating thermal bridges in pillars, beams, inter-storey facings, radiator niches; provide acoustic insulation of walls; insulation from floor noise; insulation of flat and sloping roofs; as well as fire-resistant coverings. They are available in sheets 2400 × 600 mm, 2000 × 600 mm, 1200 × 600 mm and several three thicknesses from 15 to 75 mm: • 15 mm (internal walls only) • 25 mm (external walls and ceilings) • 50 mm (external walls and ceilings) Source: Celenit: www.celenit.com

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Plasterboard Plasterboard is by far the lowest cost and most widely used lining and finishing board for walls and ceilings, adhesive or mechanically fixed and plaster finished or direct decorated. Boards with a core of aerated gypsum plaster bonded between two sheets of strong paper that should comply with BS EN 520: 2004. There are different grades for dry lining and wet plaster. Dry lining boards have tapered edges to allow for jointing tapes. Boards are available backed with foil, polystyrene, polyurethane foam and phenolic foam. Others have more moisture-resistant and fire-resistant cores. Thicknesses Sheet sizes

9.5, 12.5, 15 and 19 mm (25–93 mm for boards backed with insulation) 400 × 1200 mm 600 × 1800 mm 600 × 2400 mm 900 × 1200 mm 1200 × 2400 mm 900 × 1800 mm 1200 × 2700 mm 900 × 2400 mm 1200 × 3000 mm

Source: British Gypsum www.british-gypsum.com

Calcium silicate board Asbestos-free board mainly used for structural fire protection. Cellulose fibres dispersed in water are mixed with lime, cement, silica and fire protective fillers to form a slurry. Water is then removed from the slurry under vacuum to form boards that are transferred to high pressure steam autoclaves for curing. Denser boards are hydraulically compressed before curing. Boards can be easily cut to size and drilled for screw fixing. 9 and 12 mm thick boards are available with rebated edges for seamless flush jointing. Boards may be decorated or left untreated.

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Thicknesses Sheet sizes Fire classification Fire protection

6, 9, 12, 15, 20, 22, 25, 30, 35, 40, 45, 50, 55 and 60 mm 1220, 1830, 2440, 3050 mm long × 610 and 1220 mm wide Class 0 for surface spread of flame From 30 to 240 minutes depending on product

Source: Promat. www.promat.com

Cement particle boards These are made of Portland cement and wood particles; they are heavy, robust and fire- and water-resistant. Typical sizes: 1200 × 2400; various thicknesses from 6 mm upwards.

Gypsum fibreboards These are made of gypsum combined with cellulose fibre, producing a stronger and more impact and fire-resistant version of plasterboard without paper facings. Typical sizes: 1200 × 600 mm, 1200 × 1200 mm, 2400–3000 × 1200; thicknesses: 10 mm, 12.5 mm, 15 mm, 18 mm, square or taper-edged. Fermacell Greenline can absorb and neutralise volatile organic compounds (VOCs) due to the inclusion of keratin – derived from sheep’s wool – to its gypsum fibreboard. Fermacell Greenline Boards 1500 × 1000 × 10 mm 1500 × 1000 × 12.5 mm 2600 × 1200 × 12.5 mm 3000 × 1200 × 12.5 mm Source: www.fermacell.co.uk

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High-performance composite boards Aerogel/magnesium silicate insulation boards: have the great advantage of very low thickness – 10 mm aerogel and 3 mm magnesium silicate – and relatively high performance. Aerogel has a K-value 2/3rds of phenolic foam – meaning that a substantial reduction of heat loss – typically 50 – 60% – through solid masonry walls can be achieved within the thickness of existing plaster finishes. This can have significant advantages for historic buildings where plaster surface locations need to be maintained to suit decorative details such as cornices. Vacuum-insulated panels (VIP): have even higher performance than aerogel with K-values only a third of phenolic foam but are correspondingly more vulnerable to construction or subsequent damage destroying the vacuum – so need to be used in well-protected details or with the full knowledge and understanding of building occupiers. Both aerogel and VIP boards are substantially more costly than much thicker conventional insulated boards of the same performance.

Materials and components 401

Wood-rotting fungi Dry rot Serpula lacrymans This is the most damaging of fungi. Mainly attacks softwoods and typically occurs in wood embedded in damp masonry. It needs wood with only 20% moisture content and thrives in dark, humid conditions and so is seldom seen externally. It is able to penetrate bricks and mortar and thus can transport moisture from a damp source to new woodwork. Fruit body Mycelium (fungal roots) Damage

Tough, fleshy pancake or bracket. Yellow ochre turning to rusty-red with white or grey margins Silky white sheets, cotton wool-like cushions or felted grey skin showing tinges of yellow and lilac. Strands sometimes 6 mm thick, becoming brittle when dry Darkens wood with large cuboidal cracking and deep fissures Wood lightweight and crumbly. No skin of sound wood Wood may be warped and give off distinctive musty mushroomy smell

Wet rots These can only grow on timber with a 40–50% moisture content and tend not to spread much beyond the source of dampness.

Coniophora puteana (cellar fungus) A brown rot occurring in softwood and hardwood. The most common cause of decay is woodwork soaked in leaking water.

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Fruit body Mycelium Damage

Rare in buildings. Thin greenish olive-brown plate. Spores on minute pimples Only present in conditions of high humidity. Slender thread-like yellowish becoming deep brown or black Darkens wood, small cuboidal cracks, often below sound veneer

Fibroporia vaillantii (mine fungus) A brown rot that attacks softwood, particularly in high temperature areas. Fruit body Mycelium Damage

Irregular, white, cream to yellow lumpy sheets or plates with numerous minute pores White or cream sheets of fern-like growths Resembles dry rot in cuboidal pieces but wood lighter in colour and cracks less deep

Phellinus contiguus A white rot that attacks softwood and hardwood and is frequently found on external joinery. Fruit body Mycelium Damage

Only found occasionally. Tough, elongated, ochre to dark brown, covered in minute pores Tawny brown tufts may be found in crevices Wood bleaches and develops stringy fibrous appearance; does not crumble

Donkioporia expansa A white rot that attacks hardwood, particularly oak, and may spread to adjacent softwoods. Often found at beam ends bedded in damp walls and associated with death watch beetle.

Materials and components 403

Fruit body Mycelium Damage

Thick, hard, dull fawn or biscuit-coloured plate or bracket. Long pores, often in several layers White to biscuit felted growth, often shaped to contours in wood. Can exude yellow-brown liquid Wood becomes bleached and is reduced to consistency of whitish lint that will crush but does not crumble

Asterostroma A white rot usually found in softwood joinery such as skirting boards. Fruit body Thin, sheet-like, without pores rather like mycelium Mycelium White, cream or buff sheets with strands that can cross long distances over masonry Damage Wood is bleached and becomes stringy and fibrous No cuboidal cracking and does not crumble

Treatment Timber suffering from fungal or woodworm damage should only be treated if really necessary. Very often the damage is old, as when the sapwood has been destroyed but the remaining heartwood is sufficient for structural stability. Many defects can be cured by eliminating the source of the damp and improving ventilation. The use of unjustified treatment is contrary to the Control of Substances Hazardous to Health (COSHH) Regulations and is not acceptable. The person or company applying the treatment could be liable to prosecution. However, when there is no alternative to chemical treatment, the following action should be undertaken:

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Identify fungus. Rapidly dry out any moisture sources and improve ventilation. Remove all affected timber (about 400 mm from visible signs for dry rot) and ideally burn on site. Avoid distributing spores when handling. Treat all remaining timbers with approved fungicide. Replace with pre-treated timber.

Woodworm Wood-boring insects do not depend on damp and humid conditions, although certain species prefer timber that has been decayed by fungi. The life cycle of a woodworm is egg, larva, pupa and adult. First signs of attack are the exit holes made by the adults who emerge to mate and usually die after reproduction. The following insects can all cause serious damage and the death watch and longhorn beetle can cause structural damage. Other beetles only feed on damp wood rotted by fungi and, since they cannot attack sound dry wood, remedial action to control wood rot will limit further infestation.

Common furniture beetle (Anobium punctatum) Attacks both softwood and European hardwood and also plywood made with natural glues. It is the most widespread beetle and only affects sapwood if wood rot is present. Commonly found in older furniture, structural timbers, under stairs, cupboards and areas affected by dampness. Beetle 2–6 mm long, exit hole 1–2 mm, adults emerge May–September.

Materials and components 405

Wood-boring weevils (Pentarthrum huttonii and Euophryum confine) Attacks decayed hard and softwood in damp situations, typically poorly ventilated cellars and wood in contact with wet floors and walls. Beetle 3–5 mm long, exit hole 1.0 mm with surface channels, adults emerge at any time.

Powder post beetle (Lyctus brunneus) Attacks tropical and European hardwood, not found in softwood. Veneers, plywood and blockboard are all susceptible. Beetle 4–7 mm long, exit hole 1–2 mm.

Death watch beetle (Xestobium rufovillosum) Attacks sapwood and heartwood of partially decayed hardwoods and occasionally adjacent softwoods. Often found in old churches with oak and elm structures. Typically found in areas prone to dampness such as wall plates, ends of joists, lintels and timbers built into masonry. Beetle 6–8 mm long, exit hole 3 mm, adults emerge March–June.

Longhorn beetle (Hylotrupes bajulus) Attacks softwood, particularly in roof timber. May be overlooked in early stages as there are a few exit holes. Scraping noises audible on hot days with large infestations. Prevalent only in Surrey and SW London. Outbreaks should be reported to BRE Timber & Protection Division. Beetle 10–20 mm long, exit hole 6–10 mm oval, adults emerge July–September.

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Termites Termites are present in southern Europe and are expected to be found more frequently in southern UK as global temperatures rise. A minor infestation in North Devon was found in 1998 and treated and monitored over the next ten years showing persistence and recurrence. Termite damage to timber structures can be so severe as to cause collapse.

Treatment Fresh exit holes and bore dust on or below timbers are signs of active infestation, although vibrations may dislodge old bore dust. Chemical treatment, however, may not be necessary. See paragraph on treatment on p. 291. Identify beetle and treat timbers with appropriate insecticidal spray, emulsion or paste to destroy adults and unhatched eggs on the surface of the wood and larvae before they develop into pupae. Solvent-based products penetrate timber very effectively but have health and safety problems associated with them. Some water-based products claim to be as effective but more environmentally friendly; of these, ­boron-based products are likely to be least toxic in the environment at large. If associated with fungal decay, treat as for wood rot and use a dual-purpose remedy (i.e. anti-rot and beetle). Do not use dual-purpose products where woodworm is present in timbers that are dry and expected to remain so. Source: Recognising Wood Rot and Insect Damage in Buildings

Materials and components 407

Wood-boring beetles

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Plastics Plastics – commonly used in building Plastics are organic substances mainly derived from by-­ products of coal–gas manufacture and refining of mineral oil. These are manipulated to form long-chain molecules on which the plasticity and rigidity of the material of the products made from them depend. They are made up of three main groups: • Thermoplastics, such as polythene, vinyls and nylon, where the structure is not permanently set and which can therefore be joined by heat or solvents. • Thermosetting plastics, such as phenol formaldehyde, melamine and fibreglass, which have fixed molecular structures that cannot be reshaped by heat or solvents and are joined by adhesives. • Elastomers, such as natural rubber, neoprene and butyl rubber, which have polymers in which the helical molecular chains are free to straighten when the material is stretched and recover when the load is released.

Plastics – industrial techniques Glass-reinforced plastic (GRP) Synthetic resin reinforced with glass fibre, used for rooflights, wall panels, etc. Injection moulding Similar to die casting for moulding thermoplastics. Plastic is melted and then forced under pressure into a cooled moulding chamber. Plastic laminate Decorative laminate made up of paper or fabric impregnated with melamine or phenolic resins and bonded together under pressure to form a hard-wearing, scratch-resistant finish used primarily for work surfaces.

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Solvent welding A permanent joint made between thermoplastics by smearing both sides with an appropriate solvent before joining together. Vacuum forming Making components by evacuating the space between the sheet material and the die so that forming is affected by atmospheric pressure.

Plastics – abbreviations in general use Abbreviation

Plastic

Uses

ABS

Cold water pipes

HDPE HIPS LDPE

Acrylonitrile butadiene styrene Chlorinated polyethylene Chlorinated polyvinyl chloride Ethylene propylene diene-monomer Expanded polystyrene Ethyl tetra fluoro ethylene Ethylene vinyl acetate Glass-reinforced polyester (fibreglass) High-density polyethylene High-impact polystyrene Low-density polyethylene

MF PA

Melamine formaldehyde Polyamide (nylon)

PB PC PE

Polybutylene Polycarbonate Polyethylene

PF

Phenol formaldehyde (Bakelite) Polymethyl methacrylate (Perspex) Polypropylene Polystyrene

CPE CPVC EPDM EPS ETFE EVA GRP

PMMA PP PS

Water tanks Hot water and waste pipes Gaskets, single ply roofing Plastic foam for insulation Film for foil roof cushions Weather protective films Cladding, roofing, panels, mouldings Geo-membranes, piping Ceilings, mirrors Sheet membranes, bins, pipes, fittings Laminated plastics, adhesives Electrical fittings, washers, ropes Pipes &fittings Anti-vandal glazing Electrical insulation, membranes, piping Electrical fittings, door furniture Sanitary ware, transparent sheet Electrical insulation, piping Smoke detector cases, suspended ceiling tile

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Plastics – abbreviations in general use – continued Abbreviation

Plastic

Uses

PTFE PU PVA

Polytetrafluoroethylene Polyurethane Polyvinyl acetate (latex emulsion) Polyvinyl chloride Polyvinyl butyral Polyvinyl fluoride Urea formaldehyde Unsaturated polyester

Pipe jointing, sealing tape Insulation, paints, coatings Emulsion paint, bonding agents

PVC PVB PVF UF UP UPVC

Unplasticised polyvinyl chloride

Floor roof and wall coverings Laminated glass interlayers Protective films Glues, insulation Paint, powder coatings, bituminous felt Rainwater, soil and waste pipes, roof sheeting, doors, windows

Wall and floor tiles Traditionally – and still mostly – made in fired clay, glazed or unglazed, wall and floor tiles now encompass a huge ranges of sizes, shapes, materials, colours and finishes from the smallest mosaics at less than 10 mm to the largest porcelain slabs of over 2 square metres. Similarly, the range of materials has expanded from fired clays to include stone, glass, metals, cork (and linoleum), vinyl, laminates and carpet tiles. In parallel with the diversification of materials and performance, the installation of tiles has become more sophisticated and complex in response to the variety of substrates and performance conditions with respect, especially, to tolerance of movement and differential moisture. BS 5385 is the standard for tile installation, last updated in 2018.

Materials and components

Nails and screws

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Standard Wire Gauge (SWG) (in millimetres and inches) SWG

mm

inch

SWG

mm

inch

 1  2  3  4  5  6  7  8  9 10 11 12 13 14 15

7.62 7.00 6.40 5.89 5.38 4.88 4.47 4.06 3.66 3.25 2.95 2.64 2.34 2.03 1.83

0.300 0.276 0.252 0.232 0.212 0.192 0.176 0.160 0.144 0.128 0.116 0.104 0.092 0.080 0.072

16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

1.63 1.42 1.22 1.02 0.914 0.813 0.711 0.610 0.559 0.508 0.457 0.417 0.376 0.345 0.315

0.064 0.056 0.048 0.040 0.036 0.032 0.028 0.024 0.022 0.020 0.018 0.016 0.015 0.014 0.012

Fixings durability Stainless steel fixings generally are most durable and universally available as nails, screws, bolts and other specialist fixings. Hot dip galvanised steel structural fixings such as joist hangers, truss clips etc. suitable for all internal and sheltered uses; large scale screws, bolts etc. and simple nails also available galvanised. Small-scale threaded fixings – screws, bolts, etc. – available as sherardised – equivalent to galvanising for durability but harder and more precise – or as BZP – bright zinc plated – a shorter life coating.

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Colour The colour spectrum is made up of colour refracted from a beam of light, as through a glass prism or as seen in a rainbow. The bands of colour are arranged according to their decreasing wavelength (6.5 × 10 −7 for red to 4.2 × 10 −7 for violet), and are traditionally divided into seven main colours: red, orange, yellow, green, blue, indigo and violet. When arranged as segments of a circle, this is known as the colour circle. The primary colours are red, yellow and blue, as these cannot be mixed from other colours. The secondary colours are orange, green and purple, and the tertiary colours are produced by adding a primary colour to a secondary colour. Complementary colours are pairs of colours on opposite sides of the circle, which when mixed together make browns and greys. The term hue indicates a specific colour, defined in terms of, say, redness or blueness, but not lightness or darkness. Tone is the lightness or darkness of a colour. Adding black, white or grey to a hue reduces its intensity.

Colour systems British Standards Colour System BS: 4800 2011. Colours are defined by a three-part code consisting of hue, greyness and weight. Hues are divided into twelve equal numbers, from 02 (red/purple) to 24 (purple), with an additional 00 for neutral whites, greys and blacks. The greyness is described by five letters: (A) grey; (B) nearly grey; (C) grey/clear; (D) nearly clear and (E) clear. Weight, a subjective term, describes both lightness and greyness, so each letter is followed by a number from 01 to 58. Thus the colour ‘heather’ 22 C 37 is made up of: 22 ( violet ) C (grey/clear ) 37 (medium weight ) RAL classic colour collection This system is used within the building industry for defining colours of coatings such as plastics, metals, glazed bricks and

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some paints and lacquers. It was established in Germany in 1925 and developed over the years, is now designated RAL 840-HR, and lists 194 colours. Colours are defined by four digits, the first being the colour class: 1 yellow; 2 orange; 3 red; 4 violet; 5 blue; 6 green; 7 grey; 8 brown and 9 black. The next three digits relate only to the sequence in which the colours were filed. An official name is also applied to each standard RAL colour, e.g. RAL 6003 olive green. RAL design system This system has 1688 colours arranged in a colour atlas based on a three-dimensional colour space defined by the co-­ordinates of hue, lightness and chroma. The colours are coded with three numbers; thus reddish/yellow is 69.9 7.56 56.5. It is similar to the natural colour system except that it is based on the mathematical division of the whole visible wavelength spectrum, which is then divided into mostly 10% steps. The system can be easily used by computer programs to formulate colours. The natural colour system (NCS) The NCS was developed by the Scandinavian Colour Institute in 1978. It is a colour language system that can describe any colour by notation, and is based on the assumption that human beings are able to identify six basic colours – white W; black S (note not B); yellow Y; red R; blue B and green G. These are arranged in a colour circle, with yellow, red, blue and green marking the quadrants. These segments are divided into 10% steps, so that orange can be described as Y 50 R (yellow with 50% red). To describe the shade of a colour, there is the NCS triangle, where the base of the triangle is a grey scale marked in 10% steps from white W to black S. The apex of the triangle represents the pure colour and is similarly marked in 10% steps. Thus a colour can be described as 1080-Y50R for an orange with 10% blackness, 80% chromatic intensity at yellow with 50% red. This system allows for a much finer subdivision of colours than the BS system.

Materials and components

415

Painting Preparation Careful preparation is vital if the decorative finish applied is to succeed and be durable. It is important to follow instructions about preparing substrates, atmospheric conditions and drying times between coats. Ensure that the right product is specified for the task, and that primers and subsequent coats are compatible.

Paints Paints basically consist of pigments, binder and a solvent or water. Other ingredients are added for specific uses. Solvent-based paints and stains are now considered environmentally unsound and are increasingly being supplanted by water-based alternatives. These are less glossy and more ­water-permeable than oil paints, but are quick-drying, odourfree, and tend not to yellow with age.

Organic paints It is now possible to use totally solvent-free paints and varnishes containing 0.0% VOCs. Most paints currently on sale, both gloss and emulsion, contain solvents and VOCs although levels have been reduced in response to increasing environmental concerns. VOCs are a major contributor to low-level atmospheric pollution and the use of these compounds leads to global warming. In addition, the use of solvent-based paints is a major cause of ‘sick building syndrome,’ ‘Danish painter’s syndrome,’ asthma, allergies, chemical sensitivities and the general flu-like symptoms reported by many people using conventional paints including matt and silk wall paints.

416 Architect’s Pocket Book

Organic paints are ideal for children’s bedrooms, nurseries, kitchens and anywhere in the home, especially for people who are chemically sensitive or suffer from asthma or allergies. Primers offer protection to the substrate from corrosion and deterioration, and give a good base for undercoats. Undercoats, which are often just thinner versions of the finishing coat, provide a base for the topcoats. Topcoats provide the durable and decorative surface, and come in gloss, satin, eggshell and matt finishes. In addition to the paints listed overleaf, there are specialist paints such as: flame-retardant paints, which emit non­-combustible gases when subjected to fire; intumescent coatings, which expand to form a layer of insulating foam for structural steel; multi-colour paints, which incorporate coloured flecks, or twopart systems that use a special roller for the top coat to reveal partially the darker colour of the first coat; silicone water-­ repellent paints for porous masonry; bituminous paints for waterproofing metals and masonry; and epoxy-ester coatings to resist abrasion, oil and detergent spills.

Materials and components

417

Paints – typical products Primers

Use*

Base*

Description

Zinc phosphate acrylic Red oxide Etching Mordant solution Micaceous iron oxide

M M M M M

WB SB SB WB SB

Acrylated rubber Wood primer Wood primer/ undercoat Aluminium wood primer Alkali-resistant

M, Ms W W

BS SB WB

For all metals inside and out, quick-drying, low odour Replaces red lead and calcium plumbate for ferrous metals Factory pre-treatment for new galvanised metal Pre-treatment of galvanised metal For marine and industrial steelwork, resists pollution and high humidity For all metals, plaster and masonry, resists moisture Non-lead primer for all woods inside and out High opacity, quick-drying primer and undercoat

W

SB

P

SB

Plaster sealer Stabilising primer

P Ms

WB SB

Good for resinous woods and as sealer for creosoted and bituminous surfaces For dry walls under SB finishes, seals stains and fire damage For dry porous interior surfaces, e.g. plasterboard To seal powdery and chalky surfaces

Undercoats Exterior flexible W Undercoat all Preservative basecoat W

SB SB SB

Long-lasting, flexible, good opacity for exterior wood For use inside and out under solvent-based finishes For new and bare wood to protect against blue stain and fungal decay

Finishes High gloss Satin, eggshell, flat

all W, M, P Vinyl emulsion P Masonry – smooth Ms Masonry – textured Ms Masonry – all seasons Ms Epoxy floor Ms, C

SB SB

Alkyd high gloss for all surfaces inside and out Alkyd paints in three finishes for interior use

WB WB WB SB WB

Floor Ecolyd gloss

W, C W, M, Ms M PVC M, Ms

WB SB

Matt, soft sheen and silk finishes for interiors Contains fungicide, for dry masonry, rendering, concrete, etc. Fine granular finish, for dry masonry, etc. Flexible, smooth and good for applying in cold conditions Two-pack mid-sheen paint for interior masonry and concrete floors Quick-drying, for interior concrete and wood floors High-quality, mirror-finish gloss, low solvent content

W, M W

SB SB

Protective enamel Exterior UPVC Acrylated rubber coating Aluminium Timber preservative

SB WB SB

Protective wood stain W

SB

Exterior varnish Interior varnish Aquatech basecoat Aquatech woodstain Diamond glaze

SB WB WB WB WB

W W W W W

Glossy, protective, quick-drying, for machinery For redecoration of weathered UPVC surfaces For steelwork and masonry inside and out, good against condensation Heat resisting to 260°C, for metals and wood Coloured, water-repellent finish for sawn timber, fences, sheds, etc. Water-repellent, mould-resistant, light-fast translucent colours Transparent gloss finish for exterior wood Tough, quick-drying, durable clear polyurethane finish Flexible satin finish for bare and new wood Flexible satin coloured finish, resists peeling, blistering Clear lacquer for interior wood surfaces subject to hard wear

*C = concrete; M = metal; Ms = masonry; P = plaster; SB = solvent-based; W = wood; WB = water-based.

Source: www.akzonobel.com

418 Architect’s Pocket Book

Paint-covering capacity Approximate maximum areas for smooth surfaces of average porosity m2 /litre Preparation

Fungicidal wash Stabilising primer Etching primer Timber preservative Timber preservative

– solvent based – water based

30 12 19 10 12

Primers

Wood primer Wood primer Wood primer Wood primer undercoat Metal primer Metal primer Metal primer Acrylated rubber primer

– solvent based – aluminium – microporous – water based – solvent based – water based – zinc phosphate

13 16 15 12 6 15 6 5

Finishes

Undercoat Emulsion Emulsion Matt finish Eggshell finish Eggshell finish Microporous gloss High gloss Non-drip gloss Wood stain Exterior varnish Interior varnish Masonry paint Masonry paint Acrylated rubber

– solvent based – matt – vinyl silk – solvent based – solvent based – water based – solvent based – solvent based – solvent based – solvent based – solvent based – solvent based – smooth – textured

16 15 15 16 16 15 14 17 13 25 16 16 10 6 6

Source: www.akzonobel.com

Materials and components

419

Wallpaper coverage for walls and ceilings Approximate number of rolls required Walls

Ceilings

Measurement around walls (m)

Height of room above skirting (m) 2.3

2.4

2.6

2.7

2.9

3.1

3.2

9.0 10.4 11.6 12.8 14.0 15.2 16.5 17.8 19.0 20.0 21.3 22.6 23.8 25.0 26.0 27.4 28.7 30.0

4 5 5 6 6 7 7 8 8 9 9 10 10 11 12 12 13 13

5 5 6 6 7 7 8 8 9 9 10 10 11 11 12 13 13 14

5 5 6 7 7 8 9 9 10 10 11 12 12 13 14 14 15 15

5 5 6 7 7 8 9 9 10 10 11 12 12 13 14 14 15 15

6 6 7 7 8 9 9 10 10 11 12 12 13 14 14 15 15 16

6 6 7 8 8 9 10 10 11 12 12 13 14 14 15 16 16 17

6 6 8 8 8 10 10 11 12 13 13 14 15 16 16 17 18 19

Measurement around room (m)

No. of rolls

12.0 15.0 18.0 20.0 21.0 24.0 25.0 27.0 28.0 30.0 30.5

2 3 4 5 6 7 8 9 10 11 12

Notes: Standard wallpaper roll is 530 mm wide × 10.06 m long (21″ × 33′0″ ). One roll will cover approximately 5 m2 (54 ft 2) including waste.

Contacts/Sources RIBA companies Royal Institute of British Architects www.architecture.com RIBA Enterprises www.thenbs.com RIBA Books www.ribabooks.com

Associations, institutes and other information sources Architects Registration Board (ARB) www.arb.org.uk Architectural Association (AA) www.aaschool.ac.uk Arts Council England www.artscouncil.org.uk Association of Environment Conscious Builders www.aecb.net Barbour ABI www.barbour-abi.com Brick Development Association www.brick.org.uk

422 Architect’s Pocket Book

British Board of Agrément (BBA) www.bbacerts.co.uk British Constructional Steelwork Association (BCSA) www.steelconstruction.org British Fenestration Rating Council www.bfrc.org British Standards Institution (BSI) www.bsigroup.com Building Centre www.buildingcentre.co.uk Building Engineering Services Association www.thebesa.com Building Research Establishment (BRE) www.bregroup.com Cadw – Welsh historic monuments www.cadw.gov.wales CEDIA www.cedia.net Centre for Accessible Environments www.cae.org.uk Centre for Alternative Technology (CAT) www.cat.org.uk Chartered Institute of Architectural Technologists www.architecturaltechnology.com Chartered Institute of Building (CIOB) www.ciob.org

Contacts/Sources 423

Chartered Institution of Building Services Engineers (CIBSE) www.cibse.org The Concrete Society www.concrete.org.uk Construction Industry Council (CIC) www.cic.org.uk Department for Digital, Culture, Media and Sport (DCMS) https://www.gov.uk/government/organisations/departmentfor-digital-culture-media-sport Department for Environment Food & Rural Affairs www.gov.uk /government /organisations/department-forenvironment-food-rural-affairs Department for Transport www.gov.uk /government /organisations/department-fortransport Design Council www.designcouncil.org.uk Disabled Living Foundation www.livingmadeeasy.org.uk English Heritage www.english-heritage.org.uk Environment Agency www.gov.uk/government/organisations/environment-agency Federation of Master Builders www.fmb.org.uk

424 Architect’s Pocket Book

Forest Stewardship Council UK (FSC-UK) www.fsc.org Friends of the Earth www.friendsoftheearth.uk Glass and Glazing Federation (GGF) www.ggf.org.uk Guild of Architectural Ironmongers www.gai.org.uk Health and Safety Executive (HSE) www.hse.gov.uk Historic Buildings and Places www.hbap.org.uk Historic England www.historicengland.org.uk Historic Environment Scotland www.historicenvironment.scot Institution of Civil Engineers (ICE) www.ice.org.uk Institution of Engineering and Technology (IET) www.theiet.org Institution of Mechanical Engineers www.imeche.org Institution of Structural Engineers (ISE) www.istructe.org International Copper Association www.copperalliance.org.uk

Contacts/Sources 425

Landscape Institute www.landscapeinstitute.org International Lead Association (ILA) www.ila-lead.org Lead Sheet Association www.leadsheet.co.uk Lighting Industry Association (LIA) www.thelia.org.uk Met Office www.metoffice.gov.uk National Building Specification Ltd (NBS) www.thenbs.com National Physical Laboratory www.npl.co.uk National Trust www.nationaltrust.org.uk Natural England www.gov.uk/government/organisations/natural-england Natural Resources Wales www.naturalresources.wales Ordnance Survey www.ordnancesurvey.co.uk Planning Appeals Commission (N. Ireland) www.pacni.gov.uk Planning and Environment Decisions Wales PEDW www.gov.wales/planning-and-environment-decisions-wales

426 Architect’s Pocket Book

Planning Inspectorate (England) www.gov.uk/government/organisations/planning-inspectorate Royal Incorporation of Architects in Scotland (RIAS) www.rias.org.uk Royal Institute of British Architects www.architecture.com Royal Institution of Chartered Surveyors (RICS) www.rics.org Royal Town Planning Institute (RTPI) www.rtpi.org.uk Scottish Civic Trust www.scottishcivictrust.org.uk Scottish Natural Heritage www.nature.scot Society for the Protection of Ancient Buildings (SPAB) www.spab.org.uk The Stationery Office (TSO) www.tso.co.uk Stone Federation Great Britain www.stonefed.org.uk Timber Research and Development Association (TRADA) www.trada.co.uk Timber Trade Federation www.ttf.co.uk Town and Country Planning Association (TCPA) www.tcpa.org.uk

Contacts/Sources 427

Water Regulations Approval Scheme (WRAS) www.wrasapprovals.co.uk Water Research Centre PLC www.wrcgroup.com Which? www.which.co.uk Zinc Information Centre www.zincinfocentre.org

Manufacturers – referred to in the text ACP (Concrete) Ltd www.thomasarmstrong.co.uk Ancon www.ancon.co.uk Autopa Ltd www.autopa.co.uk Banham Security www.banham.co.uk Bison / Forterra www.forterra.co.uk BMI group www.bmigroup.com British Gypsum www.british-gypsum.com Catnic www.catnic.com

428 Architect’s Pocket Book

Celenit www.celenit.com Coxdome www.coxdome.co.uk Clayboard www.dufaylite.com Dulux www.dulux.co.uk Duplus Architectural Systems Ltd www.duplus.co.uk EnviroBuild www.envirobuild.com Envirograf www.envirograf.com GE Lighting Limited www.gelighting.com Glass Block Technology Ltd www.glassblocks.co.uk Glazing Vision www.glazingvision.co.uk Glulam Ltd www.glulambeams.co.uk Hillier Nurseries www.hillier.co.uk Ibstock Brick Ltd www.ibstockbrick.co.uk

Contacts/Sources 429

Ideal Heating www.idealheating.com Ideal-Standard (UK) Ltd www.idealstandard.co.uk I G Lintels Ltd www.iglintels.com IKO PLC www.ikogroup.co.uk James Latham PLC www.lathamtimber.co.uk JELD-WEN Ltd www.jeld-wen.co.uk Kalzip Ltd www.kalzip.com Kingspan Insulation www.kingspan.com Klober Ltd www.klober.co.uk Lakeland Paints www.lakelandpaints.co.uk Luxcrete Ltd www.luxcrete.co.uk Marley www.marley.co.uk Masonite Beams AB www.masonite-beams.com

430 Architect’s Pocket Book

Medite Smartply www.mdfosb.com Metra Non-Ferrous Metals Ltd www.metra-metals.co.uk Midland Lead Manufacturers Ltd www.midlandlead.co.uk Milbank Concrete Products Ltd www.milbank.co.uk Monodraught Ltd www.monodraught.com NCS UK Limited www.ncscolour.co.uk NorDan UK Ltd www.nordan.co.uk Osram Ltd www.osram.co.uk Pilkington United Kingdom Limited www.pilkington.com Promat UK Ltd www.promat.com Readyhedge Ltd www.readyhedgeltd.com Rheinzink www.rheinzink.co.uk Saint-Gobain UK www.saint-gobain.co.uk

Contacts/Sources 431

Signify Lighting www.lighting.philips.co.uk Sips Eco Panels www.sipsecopanels.co.uk Stowell Concrete Ltd www.stowellconcrete.co.uk Sunsquare Ltd www.sunsquare.co.uk Sylvania Lighting www.sylvania-lighting.com Tarmac www.tarmac.com Tata Steel Europe www.tatasteeleurope.com Ubbink (UK) Ltd www.ubbink.com Velfac A/S www.velfac.co.uk Velux Company Ltd VKR Holding A/S www.velux.co.uk Vent-Axia Ltd www.vent-axia.com VM ZINC www.vmzinc.com Visqueen Building Products www.visqueen.com

432 Architect’s Pocket Book

Wavin UK www.wavin.com Welsh Slate www.welshslate.com West Fraser www.uk.westfraser.com Zehnder Group UK Ltd www.zehnder.co.uk

Bibliography/Sources Building Construction McKay, W. B. 2005 Donhead Publishing Building Regulations Approved Documents 2010 The Damp House: Guide to the Causes and Treatment of Dampness Hetreed J. 2008 Crowood Press Designing for Accessibility 2012 RIBA Publishing The Green Building Bible Volume 2 4th Edition  Hall K, 2008 Green Building Press The Green Guide to Specification www.bregroup.com Green Guide to the Architect’s Job Book Halliday, S. 2001 RIBA Publishing GUIDE “A” ENVIRONMENTAL DESIGN 2015 CIBSE Landscape for 2030: How landscape practice can respond to the climate crisis LI Climate Change Case Studies. The Landscape Institute 2021 Managing Health and Safety in Construction, (Design and Management) Regulations 2015 Guidance on Regulations www.hse.gov.uk Health & Safety Executive Materials for Architects and Builders  Lyons, A. R. 2019 Routledge Mathematical Models Cundy, H. M. and Rollett, A. P. 1997 Tarquin Publications Recognising Wood Rot & Insect Damage in B ­ uildings  Bravery, A. F. 2003 BRE RIBA 2030 Climate Challenge Guide www.architecture.com RIBA Sustainable Outcomes Guide www.architecture.com Tree Species Selection for Green Infrastructure: A Guide for Specifiers, Issue 1.3. Trees & Design Action Group. Hirons, A.D. and Sjöman, H. (2019) The Which? Book of Plumbing and Central Heating Holloway, D. 2000 Which? Books WRAS Water Regulations Guide  Water Regulations Advisory Scheme (WRAS)

Index Note: Italic page numbers refer to figures. acoustic absorption 264, 265 acoustic insulation 164, 262–4, 365 Adjudication 77–8 advertising 46 aerated concrete 154, 302, 313, 334 aerogel/magnesium silicate insulation boards 400 air conditioning 87 air permeability/tightness 88, 213, 215–16, 230 air source heat pump 188 air spaces, R-values 211 alarm systems 301 alternative dispute resolution (ADR) 77 aluminium roofing and cladding 352–4, 356–7 anodising 329 anthropometric data 108–11 anti-lift devices 300 antimicrobial copper 350 appointments 76–7 Approved Documents 53–6 ARB (Architects Registration Board) 35 Architects Declare 80–1 Architects Registration Board (ARB) 35 Areas of Outstanding Natural Beauty 41, 44 asphalt roofing 360 backflow protection, water supply 198, 199 background ventilator 226

balanced flues 280 balustrades 274–7 bathrooms: dimensions 120–1; electrical socket outlets 234; lighting levels 253; ventilation 225, 227, 230; see also sanitary facilities; WCs battens, roofing 337, 340 bay windows 287 beam and block floors 184–6 beams: engineered timber 173, 174, 390–1; formulae 144, 168; Glulam 174, 390–1; steel 176–8; thermal breaks 180–1 bedrooms: dimensions 118–19; electrical socket outlets 234; noise levels 265; ventilation 230 bending moments 144, 168–9 bicycle parking 126 BIM (Building Information Modelling) 24–6, 32 bi-metal compatibility 327 Biodiversity Net Gain 93 biofuel boilers 88 bituminous fibre profiled sheets 357 bituminous membranes 360–1 blockboard 388 block paviours 315 blocks: concrete 312–13; glass 371–2 blockwork: cavity wall ties 313–14; drawing conventions 30; mortars 309; slenderness ratio 157

436 Index boards see building boards boilers: biofuel 88; combination 219; condensing 222; flues 280 bolts 411, 412 bricks: compressive strengths 306; firebrick 315; frost resistance 307; manufacture process 304–5; sizes 305–6; soluble salt content 307; special 310–11; unfired 305; water absorption 306; weights 306 brickwork: bond types 308; cavity wall ties 313–14; drawing conventions 30; joints 309; mortars 309; paving patterns 314; slenderness ratio 157 British Board of Agrément (BBA) 67 British Fenestration Rating Council (BFRC) 288 British Standards Institution (BSI) 67–8 building boards: blockboard 388; calcium silicate board 398–9; celenit 397; cement particle boards 399; chipboard 387; clayboard 397; composite decking and cladding 394; engineered floorboards 388–9; flaxboards 397; gypsum fibreboards 399; hardboard 391; high performance composite 400; impregnated fibreboards 396; insulating fibre boards 396; laminboard 388; MDF (Medium Density Fibreboard) 392; mediumboard 392; oriented strand board (OSB) 389, 392–3; plasterboard 398; plywood 395–6; SIPS panels 389; strawboards 396; timber

cladding 376, 393–4; wood wool boards 397 Building Information Modelling (BIM) 24–6, 32 Building Regulations 53–61, 212; Approved Documents 53–6; changes 57–60; chimneys and flues 279–80; drainage 188, 191, 193; energy conservation/ efficiency 212; fire resistance 145–6; Future Homes Standard 60–1; glazing 289–90, 293, 365, 367; ground gas protection 319; hot water cylinders 205; lighting 241–4; revisions and additions 56; sound insulation 263; stairs 274–7; ventilation 224–9, 291; wheelchair access 111 buildings: access to and use of 60; elements and materials 271–3; embodied carbon of 147; loading 133 Building Safety Bill of 2021 66 building services, sustainability 86–8, 214 building stones 316 bullet resistant glass 316 bush hammering 303 cabling: home technology 269–70; see also electrical installation CAD (computer-aided design) 24 calcium silicate board 398–9 carbon monoxide (CO) detectors 58 catnic steel lintels 161–2 cavity walls 154; effective thickness 157; insulation 154, 333; pressed steel lintels 161–2; ties 313–14; U-values 209 CDM Regulations 63–6

Index

ceiling joists, timber 171–2 ceilings, R-values 211 Celenit boards 397 cellular clay blocks 305 CE mark 68 cement 90, 302, 303, 309 cement particle boards 399 CEN (European Committee for Standardisation) 68 Chartered Institute of Architectural Technologists (CIAT) 36 chimneys: planning permissions 41; regulations 279–80 chipboard 387 CHP (combined heat and power) systems 88 chromium plating 329 CIAT (Chartered Institute of Architectural Technologists) 36 circuit vent pipes 200 circumference 18 CI/SfB Construction index 33–4 cisterns: cold water 199–200, 202; WC and urinal 201 cladding: condensation 334; load-bearing studwork 163–4; profiled sheet 356; structural insulated panels 389–90; timber 376, 393–4 classification systems 33–4 clayboard 397 clayware 315–16 Clean Air Act 1993 57 climate change 1–7; mitigation/ adaptation for 93 Climate Change Committee 1 climate maps 6, 8, 9 cloud computing 26 cob and clunch 304 Code for Sustainable Homes 81–2

437

cold-formed structural steel 175 cold water cisterns 199–200, 202 colour rendering index (CRI) 248, 254 colour spectrum 413 colour systems 413–14 colour temperatures 253 combination boilers 219 combined heat and power (CHP) systems 88 combustion appliances and fuel storage 57–8 comfort 84 Common Arrangement of Work Sections (CAWS) 33 compact fluorescent lamps (CFLs) 257–8 composite decking and cladding 394 computer-aided design (CAD) 24 concrete: aerated 154, 302, 313, 334; blocks 312–13; floors 183–6; grades 182–3; lintels 159–60; paving 183, 315 concrete frame 182 concrete grades 182–3 condensation 346, 359; and insulation 334–5 condensing boilers 222 Conservation Areas 44–5, 296 conservation of fuel and power 58–9 conservatories 86, 226 Construction Design and Management Regulations (CDM) 63–6 continuous mechanical extract ventilation 226 Contract Administrator (CA) 74 contracts 71–6 control of overheating 60 cooling systems, environmental design 87

438 Index copper, antimicrobial 350 copper roofing 347–50 corridors: emergency lighting 246; imposed loads 138–9; lighting levels 253; wheelchair access 111 corrosion: aluminium 354; copper 349; lead 346; stainless steel 355; zinc 352 costs 71–3 cross bracing 165 cross-laminated timber (CLT) 165 cylinders, hot water 205–6, 219, 223 dampness 61 damp-proof courses (DPCs) 317–18, 346, 402 damp-proof membranes (DPMs) 318–19 daylighting 88, 239–40 decking 170 decorative glass 370 Design Dwelling Emission Rate 212 Design Summer Year 4 dining rooms: dimensions 116–17; lighting levels 253; noise levels 265 disabled access 110–11; doors 281; dwellings 111; entrance lobbies and corridors 111; garages 124; lifts 110; ramps 110, 277; shower rooms 130; toilets 127, 129–30 dispute resolution 77–9 doors: drawing conventions 31; fire resistance 283; handing 285; security 299–300; types and sizes 282–4; U-values 208–9; wheelchair access 281; wooden 286

double check valves (DCVs) 200 double glazing 289–90 downpipes 192 DPCs see damp-proof courses (DPCs) DPMs see damp-proof membranes (DPMs) drainage: foul drains 188; inspection chamber covers 190; land drains 189; rainwater disposal 192; single stack systems 191; Sustainable Urban Drainage Systems (SUDS) 193–6; traps 189, 191; waterless waste valves 189, 191 drain taps 199 drawing: conventions 28–31; perspective 32–3; 3-dimensional hand 32 drinking water 199 driveways, planning permissions 42 dry rot 401 due diligence system, timber 374 earthenware 315 elastomers 408 electrical heating, underfloor 223 electrical installation 232–6; domestic circuits 236; fuses 233; graphic symbols 235; regulations 232; socket outlets 233–4 electricity 232 electronic security devices 301 ELVHE (extra low voltage head end) 270 embodied carbon 147; reducing in foundations 150–1; superstructure 148 embodied energy 89 emergency lighting 245–6 EMS (Environmental Management System) 68

Index

energy conservation/efficiency: air permeability/tightness 88, 213, 215–16, 230; building services 86–8, 214; embodied energy 89; environmental building design 80–6; glazing 86, 288–90, 363, 364; heat loss calculations 217; lighting 241, 254–9; regulations 212; thermal bridging 161, 162, 180, 216–17 energy consumption, domestic appliances 232–3 energy infrastructure 42 engineered floorboards 388–9 engineering units 133 ENs (Euronorms) 69 entrance lobbies, wheelchair access 111 Environment Act 2021 57 Environment Agency 45, 46, 194 environmental building design 80–6 environmental control systems 87 environmental issues see sustainability Environmental Management System (EMS) 68 EPIC classification system 33 Eurocodes 69, 131–2 Euronorms (ENs) 69 European Union of Agrément 70 European Union Timber Regulation (EUTR) 374 EV charging infrastructure 60, home charging 124 expansion valves 200 extensions see house extensions extensions of time 75 extractor fans 229–30 extract ventilation 226

439

Fabric Energy Efficiency Standard 59 fabric heat loss 217 Feed in Tariff (FIT) subsidies 87, 224 fees and appointments 76–7 felts, roofing 360 fences, planning permissions 41 Fibonacci series 21 Fibonacci spiral 22 fibreboards: gypsum 399; impregnated 396; insulating 396; medium density (MDF) 392 fibre-cement profiled sheets 357 finishes: environmental considerations 91; metals 329; windows 290, 294 firebrick 315 fireplaces 277–8 fire safety/resistance: alarms 301; fire doors 283; fire escape windows 291; fire-resistant glass 365–6; lighting 245; structural elements 145–6 FIT see Feed in Tariff (FIT) subsidies fixed light windows 287, 295 fixings 411, 412 flanking transmission 262 flashings 294, 340, 345–6, 348, 358 flat roofs: condensation 334–5; imposed loads 143; non-metallic roofing 357–61; rainwater 358; ultra-violet light damage 359; U-values 208, 209 flaxboards 397 flood defences 46 flood risk 45 floors: concrete 183–6; damp-proof membranes (DPMs) 318–19; decking 170; engineered floorboards 388–9; ground gas protection 319; imposed loads

440 Index 137–42; load-bearing studwork 164; R-values 211; timber joists 169; underfloor heating 222–3; U-values 208, 209 flues: planning permissions 41; regulations 279–80 fluorescent lighting 256–8 folding doors 283–4 Forest Stewardship Council (FSC) 373 foul drains 188 foundations 149–51, 182 fountains 201 freezing protection, water supply 198 French doors 283 frost resistance, bricks 307 fuel and power, conservation of 58–9 fungi, wood rotting 401–4 furniture and fittings data 112–26; bathrooms 120–1; bedrooms 118–19; bicycle parking 126; dining rooms 116–17; domestic garages 124; garden 123; halls and sheds 123; home electric vehicle charging 124–5; kitchens 114–15; laundry and utility rooms 122; recycling and refuse 122; vehicle sizes and parking bays 125 fuses 233 Future Buildings Standard 56 Future Homes Standard 2025 56, 60–1 galvanising 329, 412 garages: dimensions 124; doors 284; electrical socket outlets 234

gardens: dimensions 123; water supply 200–1 gas appliances: flues 280; ventilation 227 gates, planning permissions 41 General Permitted Development Order 42 geometric data 18–22 geotextile membranes 315 glazing and glass 289–90, 362–72; decorative 370; double/triple 289–90; energy efficiency 82, 289, 363, 364; environmental control 362–4; fire-resistant 365–6; gas filling 290, 364; glass blocks 371–2; laminated glass 368; leaded lights 290; low-e coatings 290, 363; lowiron glass 370; patent glazing 297–8; protection of 290, 293; safety glass 290, 293, 367–8; security 368–9; self-cleaning 369–70; solar control 362–4; sound insulation 365; thermal insulation 290, 363, 364; toughened glass 368; U-values 208, 209, 290, 363, 364 Glulam beams 174, 390–1 golden section/mean 21 Good Homes Alliance guide 4 graphics processing unit (GPU) 25–6 Greek alphabet 17 Green Belt 43 Green Blue Urban Company 97 green issues see sustainability green roofs 273 grey water systems 88 ground gas protection 319 gutters 192, 345, 348, 358

Index

gypsum: fibreboards 399; plasterboard 398; plasters 322, 324–6, 397 halls: dimensions 123; electrical socket outlets 233; ventilation 230 halogen lighting 258–9 hardboard 391 hardwoods 374–5, 380–3; mouldings 385; sizes 377, 383 hearths 278 heating systems 220–4; environmental design 87; flues 280; installation types 219; radiators 221–2; solar thermal space heating 223–4; underfloor heating 222–3 heat losses: air permeability/ tightness 88, 213, 215–16, 230; calculations 217; figures 215; thermal bridging 161, 162, 180, 216–17; ventilation 218 heat pumps: ground, water and air source 188, 222, 224 heat reclaim vent systems (MVHR) 88, 229 hedges 42, 45, 98–9 hempcrete 303 High Court 50 high-performance composite boards 400 hollowcore floors 183–5 hollow sections, steel 178–80 Home Quality Mark 82 home technology integration 234, 266–70 hose union taps 200

441

hot water systems: cylinders 205–6, 219, 223; installation types 219–21; regulations 200; requirements 204; solar thermal 87, 206, 219, 223–4; thermal stores 206, 222 house extensions: energy efficiency 213; planning permissions 38–41 Housing Grants, Construction and Regeneration Act 1996 74, 77 H-windows 288 imperial units 13; imperial/SI conversion 14–16 imposed loads: floors 137–42; roofs 143 impregnated fibreboards 396 incandescent lamps 259 Industry Foundation Classes (IFC) files 25 insects, wood-boring 404 inspection chamber covers 190 insulating fibreboards 396 insulation: hot water systems 200, 205; sound 164, 261–4, 365; thermal 86; water fittings 198 insulation, thermal: aerated concrete 154, 302, 313, 314; cavity walls 154, 333; and condensation 334–5; external 154, 333; glass 290, 363, 364; internal 154, 333; load-bearing studwork 164; materials 331–2; solid walls 154; structural insulated panels 389–90 insurance, professional indemnity 80 interim certificates 73–5 International Organization for Standardization (ISO) 69

442 Index joists: ceiling 171–2; engineered 172–3; floor 169; holes through 172 Kepler-Poinsot star polyhedra 19, 20 kerbs, rooflight 297 kitchens: dimensions 114–15; electrical socket outlets 234; lighting levels 253; ventilation 225, 227, 230 K-values 206, 207, 211, 330–2 laminboard 388 lamps 254–9; compact fluorescent (CFLs) 257–8; fluorescent 256–8; incandescent 259; LED (Light Emitting Diodes) 254–6; regulations 241–4; tungstenhalogen 258–9 land drains 189 landscape: design, drawing conventions 29; hard landscapes, trees in 95, 96; landscape design 85; landscaping 92–107; sustainability 85 laundry and utility rooms 122 leaded lights 290 lead roofing 343–6 LECA (lightweight expanded clay aggregate) 302 LED (Light Emitting Diodes) 254–6 legal involvement for architects 79–80 lifts, wheelchair access 110 lighting 88, 237–9; colour rendering index (CRI) 248, 254; colour temperatures 253; compact fluorescent lamps (CFLs) 257–8; controls 246–8; daylighting 88, 239–40; emergency 246;

energy efficiency 241, 254–9; external 241, 243; fire rating 245; fluorescent 256–8; glossary 248–52; incandescent lamps 259; LED (Light Emitting Diodes) ­254–6; recommended levels 237, 239, 253; regulations 241–4; sunpipes 298; tungstenhalogen 258–9 lightweight aggregate concrete 302 lightweight expanded clay aggregate (LECA) 302 limecrete 303 lime mortars 157, 309; see also rendering lime-scale 203 linear fluorescent lamps (LFLs) 256–7 lintels 159; catnic steel 161–2; for masonry construction 159–62; precast concrete 159–60; pressed steel 159, 161 Listed Building Consent 44 Listed Buildings 38, 44, 296 living rooms: electrical socket outlets 233; lighting levels 253; noise levels 265; ventilation 225, 228, 230 load-bearing studwork 163–4 loading: beam formulae 144, 168; bending moments 144, 168; building 133; floors 137–42; Glulam beams 174; imposed loads 137–43; inspection chamber covers 190; precast concrete floors 183–6; precast concrete lintels 159–60; roofs 143; safe loads on subsoils 152; snow 143; universal beams 176–7; wind 143, 155, 163

Index 443

longstrip copper roofing 347–9 low carbon design 147–8 low-iron glass 370 mains pressure cylinders 205 masonry design checks 157–8 masonry structures 154–5; chimneys 279; drawing conventions 30 mastic asphalt roofing 360 materials: acoustic absorption 264; drawing conventions 30; embodied energy 89; environmental considerations 89–90; sound insulation 262; sourcing 89–90; thermal conductivity 211, 330–2; thermal insulation 330–4; toxicity 89; weights 134–6 mechanical ventilation 228 mediumboard 392 medium density fibreboard (MDF) 392 metal roofing and cladding 343–57; aluminium 352–4, 356–7; copper 347–50; lead 343–6; profiled sheet 356–7; stainless steel 354–5; zinc 351–2 metals 327–9; antimicrobial copper 350; bi-metal compatibility 327; finishes 329; industrial techniques 328–9; see also metal roofing and cladding; steelwork metal structural framing systems (SFS) 175 Metaverse 26 Method of Assessment and Testing (MOAT) 69 metric units 10–11 MOAT (Method of Assessment and Testing) 69

model viewing software 25 mortars 154, 309, 317; see also rendering movement joints 157 nails 411, 412 National Parks 41, 44 Natural Colour System (NCS) 414 NBS 33 newtons 133 noise levels 260, 265 non-domestic buildings: emergency lighting 245–6; fire resistance 145; hot water requirements 204; imposed floor loads 137–42; lighting levels 237, 239, 253; lighting regulations 242–4; noise levels 265; recommended indoor temperatures 215; sanitary provision 126–30; ventilation 230 Norfolk and Suffolk Broads 41, 44 open flued appliances, ventilation 227 Operation and Maintenance Manuals 59 organic paints 415–16 oriented strand board (OSB) 389, 392–3 overheating, in homes 4 paints/painting 415–18 paper sizes 23 parallel-strand lumber (PSL) 173 parking/car parks: bay dimensions 125; bicycle 126; fire resistance 145; imposed loads 142; ramp gradients 277; see also garages

444 Index party walls: awards 50–2; U-values 208, 209 Passive Infra-red (PIR) flush controls 201 passive solar design 85–6 passive stack ventilation 88, 225–6 Passivhaus 83–4; classes 84; performance criteria 84; principles 83; standards 81, 290, 333 paving: brickwork patterns 314; concrete 183, 315; permeable 194, 315; slabs 315 permeable paving 194, 315 permissible stress 173 permitted development 37, 40 perspective drawing 32–3 photovoltaics 87, 220, 223–4 piled foundations 150 pitched rooflights 294–5 pitched roofs: imposed loads 143; U-values 208, 209 planning: appeals 47–50; permissions 36–43; permitted development 37, 40 plaster: glossary 321–3; pre-mixed 324–6; see also rendering plasterboard 398 plastics 361, 408–10 Platonic solids 19, 20 plywood 395–6 pocket doors 284 pollution 89 polyhedra 19, 20 pools, garden 201 porches, planning permissions 39 powder coating 329 precast concrete floors 183–6 precast concrete lintels 159–60

prefabrication 71–2; load-bearing studwork 164–5; timber roof trusses 173–4 pressed steel lintels 161 primary energy demand (PER) 84 principal designers 63–6, 77 Probabilistic Climate Profiles (ProCliP) 3–4 professional bodies 35–6 professional indemnity insurance 80 profiled sheet roofing 356–7 public buildings: emergency lighting 245–6; fire resistance 145; hot water requirements 204; imposed floor loads 137–42; lighting levels 237, 239, 253; lighting regulations 242–4; noise levels 265; recommended indoor temperatures 215; sanitary provision 126–30; ventilation 230 purge ventilation 228 Quality Management System (QMS) 70 quantity surveyors 71–4, 78 racking resistance 163 radiators 221–2 radon protection 319 raft foundations 150 rainfall 2, 192; annual averages map 8 rainwater: collection systems 88; downpipes 192; flat roofs 358; gutters 192, 345, 348, 358 RAL Classic Colour Collection 413–14 RAL Design System 414 rammed earth 303

Index 445

ramp gradients 277; drawing conventions 28; wheelchair access 110, 277 real-time rendering 25–7 recycling and refuse planning 122 regular solids 19–20 regulations: Construction Design and Management (CDM) 63–6; water supply 196–201; see also Building Regulations relief valves 200 rendering 320–1; glossary 321–3 renewable energies 87, 213; passive solar design 85–6; solar photovoltaics 87, 223–4; solar thermal systems 87, 206, 219, 223–4; wind turbines 87 Renewable Heat Incentive (RHI) subsidies 87, 224 reverberation time 264 RIAS (Royal Incorporation of Architects in Scotland) 36 RIBA (Royal Institute of British Architects) 35–6, 76, 80 rights of way 46 rocks: safe loading 152; types 316 Roman numerals 17 roofing and cladding 335–61; aluminium 352–4, 356–7; battens 337, 340; bituminous membranes 360–1; copper 347–50; felts 360–1; flashings 294, 340, 345–6; lead 343–6; mastic asphalt 360; non-metallic flat roofs 357–61; profiled sheet 356–7; sarking membranes 337; shingles 335, 338–40; single ply membranes 361; slates 335, 337; stainless steel 354–5;

thatch 341–2; tiles 335–7; ultraviolet light damage 359; uPVC/ polypropylene accessories 338; zinc 351–2 roofs: condensation 335–6, 346, 359; extensions 40; imposed loads 143; load-bearing studwork 163–4; pitched rooflights 294–5; prefabricated timber trusses 173–4; rainwater on flat roofs 358; R-values 211; U-values 208, 209 Royal Incorporation of Architects in Scotland (RIAS) 36 Royal Institute of British Architects (RIBA) 35–6, 76, 80; Plan of Work 2020 91–2; Sustainable Outcomes Guide 91–2 R-values 207, 211, 330 safes 301 safety: emergency lighting 245–6; window protection 290, 293; see also fire safety/resistance safety glass 290, 293, 367–8 sanitary facilities: dimensions 120–1; disabled access 127, 129–30; drainage systems 188, 191; lighting levels 253; public buildings 126–30; traps 188, 191; ventilation 225, 227, 230; water supply regulations 196, 199, 201 sarking membranes 337 satellite dishes/antenna 42 screws 411, 412 sea areas map 9 security: alarms 301; electronic devices 301; fittings 299–300; glazing 368–9; safes 301

446 Index services engineers 76 sheds, dimensions 123 sherardising 329, 412 shingles, roofing 335, 338–40 shower rooms 120; wheelchair access 130 single ply membranes 361 single stack drainage system 191 site layouts 85 SI units 10–12; SI/imperial conversion 14–16 slates, roofing 335, 337 slenderness ratio 157 sliding doors 283–4 snow loading 143 software: BIM 24–6, 32; CAD 24; model viewing 25 softwoods 374–5, 378–9; mouldings 384; sizes 377 soil pipes 41, 191 soils, safe loading 152 solar control glass 362–4 solar gain see passive solar design solar photovoltaics 87, 223–4 solar thermal systems 87, 206, 219, 223–4 solid fuel appliances, ventilation 227 sound 260–6; absorption 264–5; acoustic absorption 264; insulation 164, 261–4, 365; noise levels 260, 265; reverberation time 264 space heating energy demand 84 stainless steel roofing 354–5 stairs: drawing conventions 28; emergency lighting 246; lighting levels 253; loads 139; regulations 274–7

standards 67–70 standard wire gauge (SWG) 412 steel frame construction 176 steel roofing 354–5 steelwork: catnic steel lintels 161–2; hollow sections 178–80; pressed steel lintels 161; thermal breaks 180–1; universal beam 177; universal column 177–8 stone 151 stoneware 315 stonework 30, 316–17 stop valves 199 stove enamelling 329 Strategic Flood Risk Assessment 45 strawboards 396 strip/trench fill foundations 150 structural engineers 76, 131, 132 structural insulated panels (SIPs) 389–90 structural masonry 154 subsoils, safe loading 152 substructure 149–51 SUDS (Sustainable Urban Drainage Systems) 193–6 sunlight: daylighting 88, 240; roofing damage 359 sunpipes 298 superstructure 148, 153 surface areas 18 sustainability 80–107; architects’ responsibilities 81–2; building services 86–8, 214; embodied energy 89; environmental building design 80–6; finishes 91; landscape design 85; land use planning 85; materials 89–90; timber 373–4; transport 85; urban planting and water

Index

management 97; see also energy conservation/efficiency Sustainable Urban Drainage Systems (SUDS) 193–6 taps: drain 199; hose union 200 Target Emission Rate 212 technology see home technology integration temperatures 2; annual averages map 6; colour 253; recommended indoor 215; units/ scales 12 terne coating 329 thatch 341–2 thermal breaks 180–1 thermal bridging 161, 162, 180, 216 thermal conductivity 206, 207, 211, 330–2 thermal insulation see insulation, thermal thermal mass 86 thermal resistance 207, 211, 330 thermal resistivity 207, 211, 330 thermal stores 206, 223 thermal transmittance 207; see also U-values thermoplastics 361, 408 thermosetting plastics 361, 408 3-dimensional hand drawing 32 tiles, roofing 335–57 tilt and turn windows 288 timber: beam formulae 168–9; beams, preliminary sizing of 168–9; ceiling joists 171–2; cladding 376, 393–4; classes of 375–6; decking 170; doors 286; drawing conventions 30; dry rot 401; due diligence

447

system 374; durability 375; engineered floorboards 388–9; engineered joists/beams 172–4, 390–1; floor joists 169; fungal attack 401–4; Glulam beams 174, 390–1; hardwoods 374–5, 380–3; moisture content 375; mouldings 384–5; plywood 395–6; post and beam 165; prefabricated trusses 173–4; sizes 376–7, 383; sleepers 151; softwoods 374–5, 378–9; strength classes 166–7; sustainability 373–4; veneers 386; wet rots 401–4; windows 292; woodworm 404–7; see also building boards timber construction 163–5 toilets see WCs toughened glass 368 toxicity of materials 89 transport 85 traps 189, 191 Tree Preservation Orders 44–5 trees: and foundations 149–50; in hard landscapes 95, 96; hardwood timber 380–2; planning permission 42; preservation orders 44–5; softwood timber 378–9; species for planting 100–7 Trees and Design Action Group (TDAG) 94 trickle ventilation 59 triple glazing 289–90 trusses, prefabricated timber 173–4 tungsten-halogen lighting 258–9 turning circles 125

448 Index UEAtc (European Union of Agrément technical committee) 70 UKCA (UK Conformity Assessment mark) 70 UKCP09 climate projections 2 ultimate limit state (ULS) 131 ultra-violet light, roofing damage 359 underfloor heating 222–23 unfired bricks 305 unfired clay bricks 305 Uniclass classification system 33, 34 universal beams 177 urban tree planting, guidelines for 94–7; hedge list 98–9; tree list 100–7 urinals 121, 126, 128, 189, 201 utility rooms: dimensions 122; electrical socket outlets 234; ventilation 225, 227, 228, 230 U-values 207–9; calculating 207; construction elements 208–9, 213; glazing 208, 209, 289–90, 363, 364; insulation materials 330; structural insulated panels 389 vacuum-insulated panels (VIP) 400 vapour control layers 360 vehicle sizes 125 veneers: wood 386; see also building boards ventilation: extractor fans 229–30; ground gas protection 319; heat losses 218; passive stack 88, 225, 226; regulations 224–9, 291; systems 57, 88, 229; window ventilators 291 vent pipes: hot water systems 200; planning permissions 41; single stack drainage 191

virtual reality 26 vitreous china 315 vitreous enamelling 329 vitrified clayware 315, 316 volatile organic compounds (VOCs) 399, 415 volumes 18 wall and floor tiles 410 wallpaper 419 walls 154; cavity wall ties 313–14; damp-proof courses (DPCs) 317–18, 346, 348; effective height and thickness 157–8; insulation 154, 333; loadbearing studwork 163–4; planning permissions 41; R-values 211; slenderness ratio 157; structural insulated panels 389; U-values 208, 209, 333, 389; see also brickwork washbasins 121, 126–8, 189 water: cold water storage 199–200, 202; fluid categories 197–8; hardness 203; softeners and conditioners 203; see also hot water systems water consumption: hot water 204; reducing 88; reduction measures 204–5; WCs and urinals 201 waterless waste valves 189, 191 water supply regulations 196–201 WCs: dimensions 121; disabled access 127, 129, 130; drainage systems 188, 191; lighting levels 253; public buildings 126–30; traps 189, 191; ventilation 225, 227, 230; water supply regulations 199, 201 weather forecast areas map 9

Index 449

weather stripping 290 wet rots 401–4 wheelchair access 110–11; doors 281; dwellings 111; entrance lobbies and corridors 111; garages 124; lifts 110; ramp gradients 277; ramps 110; shower rooms 130; toilets 127, 129 wildlife 47 wind loading 143, 155, 163 windows 287–98; bay 287; curved shapes 291; double/ triple glazing 289–90; drawing conventions 31; energy efficiency 82, 288–90; finishes 290, 294; fire escape 291; fittings 291, 294, 300; kerbs 297; leaded lights 290; pitched rooflights

294–5; protection of 290, 293; rooflights 296–8; security 300; side and top hung casements 287; sunpipes 298; types and sizes 287; U-values 208, 209, 290; ventilators 291; weather stripping 290; wooden 292; see also glazing and glass wind posts 154, 157 wind turbines 87 wireless connections (Wi-Fi) 269 wiring: home technology 268–9; see also electrical installation wood see timber wood screws 411, 412 woodworm 404–7 World Heritage Sites 41, 44 zinc roofing and cladding 351–2