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A single copy of this document is licensed to
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Guide to buildingservices for historicbuildingsSustainable
services fortraditional buildings
CIBSEThe Chartered Institution of Building Services Engineers222
Balham High Road, London S W 2 9BS
Maldngbusfnessyllyofclimate change
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The rights of publication or translation are reserved.No part of
this publication may be reproduced, stored in aretrieval system or
transmitted in any form or by anymeans without the prior permission
of the Institution.
November 2002 The Chartered Institution of BuildingServices
Engineers LondonRegistered charity number 278104ISBN
1-903287-30-8This document is based on the best knowledge available
a tthe time of publication. However no responsibility of anykind
for any injury, death, loss, damage or delay howevercaused
resulting from the use of these recommendationscan be accepted by
the Chartered Institution of BuildingServices Engineers, the
authors or others involved in itspublication. In adopting these
recommendations for useeach adopter by doing so agrees to accept
fullresponsibility for any personal injury, death, loss, damageor
delay arising out of or in connection wi th their use by oron
behalf of such adopter irrespective of the cause orreason therefore
and agrees to defend, indemnify andhold harmless the Chartered
Institution of Building ServicesEngineers, the authors and others
involved in theirpublication from any and all liability arising out
of or inconnection with such use as aforesaid and irrespective
ofany negligence on the part of those indemnified.Typeset by ClBSE
Publications Department
Printed in Great Britain by Page Brothers, Norwich.
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AcknowledgmentsThis Guide originated in a proposal to CIBSE by
Ma rtin Cook AAD ip MPhil(Cantab) RIBAof the Buildin g Research
Establishment. Wit hout M artin's perseverance over a num ber
ofyears, it would not have been completed. It has been drafted by
Peter Warm CE ng MCIBSEM SL L and R ichard O xley BSc DipBldgCons
MRICS IHBC, with funding from the CarbonTr ust unde r th e Action
Energy programme. Picture research and case study collation
wereundertaken by Catharine Bull. Assistance was provided by Dr W T
Bordass. Martin Cookalso drafted one of the case studies. The
project was supervised by a ManagementCommittee an d received
invaluable advice and support from an Advisory Panel. T han ks
arealso due to Noel B urns of BRE for his strategic
help.Information for the case studies has been provided by many
people, too numerous to listhere. F ull details are available on
the C IBSE website www .cibse.org.Photographs have been provided by
the following individuals and organisations: RichardOxley,
Catharine Bull, Peter Warm, Douglas K ent (SPAB), John P reston
(Cambridge CityCouncil), James Th orpe (Klober Ltd), Paul Jennings
(Retrotec Europe Ltd), Joh n Young(Bath 8z NE Somerset Council),
Martin C ook (BRE), Richard A tkins, Ian M ilford (Atkins),John W
inter (John W inter 8z Associates), Th e National T rus t (T he
Vyne, p. 42), AnnePhilps (Martin Thomas Associates), James
Featherstone (Tuffin Ferraby z Taylor), BobSandford (Julian Harra p
Architects), Neil Ha milton (Design Consultancy), David G
ibbons(Urban Projects Ltd), Brough Skingley (English Heritage),
Laurie Jonas, WarwickSweeney (RICS Awards), Michael Davies (Davies
Sutton Architecture), Brian F ord (WSP),Peter CookNiew, Ingval
Maxwell (Historic Scotland), Bob Ferris (CIBSE BuildingServices
Heritage Group), G lasgow School of Art, Silabhadra Sen (Palace of
Westminster,p. 73).Management CommitteeChairman:David Bailey (James
Joy - David Bailey Partnership)Members: Ma rtin C ook (BRE),
Jonathan David (CIBSE), Derek Lawrence (CIBSE), VerneyRyan
(BRE).Advisory PanelRichard Atkins; Douglas Hogg (Cadw); Ingval
Maxwell (Historic Scotland); Ian Milford(Atkins); Brough Skingley
(English Heritage); Sarah Staniforth (National Trust); TimYates
(BRE).CIBSE Publications ManagerJacqueline BalianCIBSE Co
ordinating EditorJonathan DavidNote from the publisherThis
publication is primarily intended to provide guidance to those
responsible for thedesign, installation, commissioning, operation
and maintenance of building services inhistoric buildings. It is
not intend ed to be exhaustive or definitive and it will be
necessaryfor users of the guidance given to exercise their ow n
professional judgm ent when decidingwhether to abide by or depart
from it.Tha nks are due to the following bodies for their support
du ring preparation of thispublication
H I S T O R I C S C O T L A N DR THE NATIONAL TRUSTC A D WWSI
PI, nis menc w w r t u z x n
E N G L I S H H E R I T A G E
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ContentsForeword by Simon Thu rleyChief Executive, English
Heritage
'v i
Preface v i i1 Principles
1 . 1 General1.2 Scope and definitions1.3 Aim of this Guide1.4
Target audience1 . 5 T he relationship between b uilding services,
energy efficiency and
conservation of the existing building stock and the environm
ent1.6 Legislation1.7 Building R egulations1.8 Design principles1.9
Summary of design principles appropriate for work in
older buildingsSim ple nonintrus ive ways of impro ving energy
efficiency.10 7
2 Building services 72.1 Modern expectations and standards of
service 72.2 Increasing sustainability 72.3 T he value of historic
building services 102.4 Re-using existing services 112.5 Criteria
for th e selection of new building services in 11
historic building s2.6 Installing new building services and
upgrading existing ones 11
3 Building fabric 153.1 Moisture m ovement in older buildings
153.2 Adding insulation 173.3 Ventilation, draughtproofing and fan
pressurisation testing 183.4 Therm al mass and controls 193.5
Conservation heating 193.6 Initial and ongoing monitoring 20
4 A design approach for historic bui ldings4.1 Introduction4.2 T
he project team4.3 An approach4.4 Design principles4.54.6
Commissioning4.7 Into th e future
Th e RIBA Plan of Work
2020212121242626
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5 Case studies5.1 Introduction to case studies5.1 Table of case
studies in dicating relevance of eachGlossaryReferencesFurther
readingUseful contactsIndex
27272776
81828384
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Foreword
Throughout my career, working in historic buildings, I have
frequently beenfrustrated by building services engineers who,
despite their best intentions, havebeen unsympathetic towards the
important structures in which they work. Thislack of sympathy
normally arises from a tension between the requirements ofowners
and occupiers who wish to benefit from 2lst-c entury technology and
t heneeds of the historic building, both in its fabric and in its
appearance. Mostengineers do not have th e experience or knowledge
to reconcile these competingpriorities adequately.Yes, mod ern
technology and old buildings need n ot be enem ies. English H
eritagebelieves that it is essential to give Englands historic
built environm ent a long-termeconomic future and part of this m
ust be fin ding ways to service historic buildingsthat are
compatible with conservation and aesthetics. Th is Guide is an
importantstep in helping bu ilding services engineers to understand
the problems of workingin historic buildings and providing the m w
ith an opp ortunity to learn from bestpractice.
Simon ThurleyChief Executive, English HeritageOctober 2002
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Preface
If you are about to install, upgrade or renew the services or
make alterations toimprove the en ergy efficiency of an existing
building, it is importan t to ask:Is the bu ilding historic orof a
traditional construction?If it is, you m ust stop and think before
taking any fur ther action. In m ost cases, thebuild ing services
in a buildin g last typically 15 to 30 years, a fleeting event in
th elife of an histo ric building. F or example, some parish chu
rches are over 1000yearsold.Energy-efficient systems and improved
thermal performance will save on runn ingcosts, maintain comfort
and reduce carbon dioxide emissions. However, anyalterations or
changes to the building services in a traditional building
requirecareful plann ing to ensu re that the proposed work w ill be
effective and beneficial.Whe n plan ning alterations, you need to
develop a thorough und erstanding of thetypes of construction, the
materials used and the likely impact of any proposedchanges. Modern
materials and techniques can often be incompatible withtraditional
construction, and careless alterations can cause serious harm to
thebuildin g fabric, both directly and indirectly.Acting without
thinking can be damaging, for the building and for theenvironment.
This Guide will help you to avoid this, so that th e existing
buildingstock can be managed and maintained in a more sustainable
manner. It alsoillustrates best practice for techniques co mm only
used in planning, installing andupgrading building services.When
installed in an app ropriate and sympathetic manner, b uilding
services canassist the preventive conservation of historic
buildings, prolong their lives inbeneficial use, improve the
internal environment, and so bring immense culturaland
environmental benefits. Building conservation is a sustainable form
ofproperty developmentT h e case studies starting on page 27
illustrate many issues that were taken intoaccount in making
approproate and efficient alterations; and the often
imaginativesolutions tha t results.
Peter Warmand Richard OxleySeptember 2002
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Figure 1 What so often happensThi s chancel screen in a Grade I
l isted church was insensit ively punched through with heating
pipework. Th escreen is thou ght to have Tud or origins and was
untouc hed from t he Jacobean period (1603-1689) until thisrecent
act of vandalism. Simply stopping and thinking of more app ropriate
and less damaging routes beforework started would have redu ced
greatly th e physical damage to irreplacemable hsitoric fabric; and
might haveavoided it altogether.
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1
Guide to building services for historic buildings
1 Principles1 I GeneralPut at its simplest, sustainability is
about ensuring that theactivities that we have to cany out to meet
our range of needscan be continued indefinitely. To do this, we
must ensure thatthese activities, whether they are power
generation, farming,waste disposal or tourism, do not irreversibly
damage theenvironment and its assetsEnglish Heritage, Sustaining
the historic environment ()T h i s G u i d e i l l u s t r a t e s
h o w o n e c a n p u t s u s t a i n a b l ed e v e l o p m e n t
i n t o e v e r y da y p ra c t ic e w h e n u p g r a d i n gb u i
l d i n g s e r vi c e s i n t h e e x i s t i n g b u i l d i n g
s t o c k . I tpromotes a holistic and interdisciplinary approach
basedon an appreciation and understandin g of:( i ) t h e h i g h l
y i n d i v i d u a l n a t u r e o f m a n y o l d e rbuildings,
reflecting the unique manner in whichthey have developed over
time;
the materials and m ethods of construction;the existing and
inten ded performance; andthe formal recognition and protection
offered bylegislation.
( i i )( i i i)zv)
Many older buildings give a special value and interest toou r
cul ture: they are of archi tectural and/or h is tor icali m p o r
t a n c e a n d t h e i r m a t e r i a l s a n d m e t h o d s o
fconstruction are no longer in common use. Their perfor-mance
characteristics are different from those of modernb u i l d i n g s
. T h e i r f o r m a l r e c o g n i t i o n b y l e g i s l a t i
o n ,Bui ld ing Regula t ions and Br i t i sh S tandards p laces
anob l iga tion on those who work w i th o lder bu i ld ings
toreflect and take account of these qualities.Older buildings are a
nonrenewable resource which needsto be t reated as such. This Guide
highlights basic prin-c i pl e s t o c o n si d e r w h e n w o r k
i n g w i t h t h e m . T h e i rindividuality prevents it being
prescriptive t identifiesissues that should to be taken into
account, but each casemust be considered on its own merits.T h e i
m p o r t a n t a n d s e n s i ti v e n a t u r e o f m a n y o l
d e rbuildings an d their fabric demand s that work on them:( a ) i
s car r ied out in an appropr iate and compat iblemanner ;b ) t a k
e s p r o p e r a c c o u n t o f t h e w a y t h e y w e r e
constructed an d were intend ed to perform;(c) causes the minim
um amount of intervention; and( d ) is reversible wh erever
possible.It is recognised as a global priority to continue to use
thee x i s t i n g b u i l d i n g s t o ck w h i l e i m p r o v i
n g i t s e n e r g y
efficiency.(*) If we are to achieve w orthwhile progress
inachieving sustainable development and reducing carbond i o x i d
e e m i s s io n s , w e n e e d t o i n c r e a s e t h e e n e r
g yefficiency of all the UKs existing buildings, not just the500000
or so that are listed as of architectural or historicinterest. This
Guide therefore covers not only historicbuildings but all buildings
of traditional construction.
1.2 Scope and def in i t ionsT h i s Guide i s a imed a t bo th
historic a n d traditionalbuildings.1.2.1 Histor ic build ing sA p
p r o v e d D o c u m e n t s L1 a n d L o f t h e B u i l d i n
gregulation^(^) treat the following as special cases whichneed to
be considered on their individual m erits:( i ) listed buildings;(
i i )( i i i)
buildings situated in conservation areas;b u i l d i n g s o f l
oc a l a r c h i t e c t u r a l o r h i s t o r i c a linteres t
and w hich are refer red to as a mater ialconsideration in a local
authoritys developmentplan; and
( i v ) b u i l d i n g s w i t h i n n a t i o n a l p a r k s
, a r e a s o fou t s t and ing na tu ra l beau ty and wor ld her i
t agesites.Additional legislation formally protects scheduled
ancientm o n u m e n t s , l i s t e d b u i l d i n g s a n d b u
i l d i n g s i n c o n -servation areas.Be f o re t h e s t a r t
of p l a n n i n g a n d d e s i g n o f b u i l d i n gservices
and energy-efficiency measures, all historic andt r ad i t iona l
bu i ld ings o t j us t t hose wi th s t a tu to ryprotection eed
care and attention to understand whatthey are, how they work and
the performance required.Th is background wi l l then dictate the
appropr iateness ,compatibil i ty and nature of alteration and
improvementthat can be carried out.1.2.2 Tradit ional build ingsF o
r t h e p u r p o s e of t h i s G u i d e , t r a d i t i o n a l
b u i l d i n g sinclude not only buildings formally recognised for
theirarchi tectural or his tor ic interes t , but a l l bui ldings
tha tneed to be approached in a manner which ref lects
theindividual characteristics of their co nstruction.Tradi t ional
ly cons t ructed bui ldings can be of any s ize,s h a p e o r f o r
m . C o n s t r u c t i o n m a t e r i a l s a r e d iv e r se
,sometimes even in a single building. W alls are no t only ofs tone
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timber frames (often with thin render or weatherboardcladding,
or with infill between the structural timbers).
Most modern buildings are made of hard, strong andimpervious
materials. To exclude moisture, they rely onphysica l barrie rs
such as dam p-pr oof courses andmembranes, cavity walls and
cladding. Historic and
traditional buildings are completely different. Many havesolid
walls and most have porous fabric which bothabsorbs and readily
allows the evaporation of moisture.This is often known as the
ability of the building fabric to'breathe', i.e. to have a low
vapour resistance. It is ofteninappropriate to repair such
buildings with modernmaterials. For example, if soft sandstone
walls arerepointed with hard Portland cement rather than soft
limemortar, not only will they look different and lose
theirattractive patina of age, but the new pointing may wellcause
the sandstone to weather badly, spall and erode while the hard
cement remains (see Fig. 20 on page 16).
Traditional buildings account for one-quarter of the
UK'sexisting building stock. Making appropriate and
efficientalterations to them as opportunities arise will be a
positiveand worthwhile contribution to reducing carbon
dioxideemissions.
Figure 2 shows the proportion of UK buildings to whichthe
principles in this Guide may apply. Although mosthistoric buildings
are of traditional construction, somelisted buildings are
relatively new, or include highlyinnovative or unusual construction
methods, needingspecial consideration. Examples are shown in the
casestudies in Section 5 (e.g. case study 7).
1.3 Aim of thisGuide
This Guide aims to make a sustainable approach tohistoric and
traditional buildings an everyday activity, notthe exception.
Recognition of the special characteristics ofthese buildings and
how best to meet their needs will be afundamental step towards the
better and more sustainablemanagement of these existing resources.
By adopting goodpractice, one can simultaneously achieve social,
cultural,economic and environmental benefits.
Within an overall aim to improve both the internalenvironment
and energy efficiency, it is important to takeaccount of the
particular circumstances of the buildingand to balance all the
issues. For example:
Historic
Traditional - 3%
Traditional - 22%
Modern - 75%
Historic
modern
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Pr inc ides 3
Aim 4: Specify environmentally conscious materialsAssess the w
hole l i fe cos ts of new an d ex is t ingmaterials before mak ing
changes.A s s es s t h e i m p a c t o f ne w m a t e r i a l s o n
t h eenvironment.Assess the impact of new materials on the hea lth
ofboth those who install them and the users of thebuildings.
1.4 Target audienceT h i s Guide will help all tho se who
specify, install o r wishto improve the services and energy
efficiency of buildingsof t radi t ional cons t ruct ion par t
icular ly those formal lyidentified as of architectural or h
istoric interest, e.g.
1.5
building services engineersprincipal a nd specialist
contractorsmanufacturers and suppliersstructura l
engineersarchitectsbuilding surveyorsquantity surveyorsmainten ance
a nd facilities managersproject managers and cost
consultantsclients uilding owners and usersregistered installers of
equip m ent (e.g. FENSA forw i n do w s , O F T E C f o r o i l - f
i re d h e a t i n g i n s t -allations an d C ORG I for gas
installations)building control officers (and external providers
ofbuilding control services)conservation officers (and nominated
officers ina r e as w h i c h h a v e n o d e d i c a t e d c o n s
e r v a t i o nofficer)historic building inspectorates and th eir
advisersfun din g bodies an d their professional
advisersconservators and historic building specialists whomay not
themselves real ise the extent to whichenergy and bu ilding c
onservation objectives can beharmonised.
The relationship betweenbuilding services energyefficiency and
Conservation ofthe existing bui lding stock andthe environment
'It is depressing, at a time when highly sophisticated plant
isbeing used for environmental control, to realise that
throughoutmuch of history, buildings themselves were highly
developedexamples of appl ied sc ience , achiev ing high leve ls
ofperformance even when designers could not define or quantifjthe
factors that they took into account.'Peter Burberry, Deteriorating
design 1978)
T h i s Guide illustrates the principal factors which need tobe
taken into acco unt to achieve more sustainable ways ofimproving
the building services and energy efficiency ofexisting buildings,
and to obtain an appropriate balancebetween historic building
conservation and energy con-servation.Th ere is a complex
relationship between building services,energy e ff ic iency, a i r
an d m ois tu re movement a nd theconservation of the ex is t ing
bui lding s tock. If only o nepart of this is considered (e.g.
building services, historicbuildings or energy efficiency) the
oversimplified view canlead to po ten t i a l danger s to the bu i
ld ing , the h i s to r i cf abr i c and the env i ronment . Even
apparen t ly f ami l i a rthings should not be taken for granted.
For example, atBerg Cot t age ( case s tudy 2 ) m a n y p e o p l e
w o u l d h a v eexpected the old single-glazed windows to have
been themain source of high air infiltration, and have wanted
toupgrade or replace them. In fact, most of the excess aircame
throu gh the fabric, especially the walls.T h e three pil lars of
global sustainabili ty, und erp inni ngthis Guide,
are:Environmental: conserving our environm ent; issues such
asglobal warming, pollution, biodiversity;Social: ensurin g that
hum an needs are met; issues such asemploym ent, self governm
ent;Economic: ensu r ing th at resources are avai lable; i s
suessuch as funding, comparing schemes,
developingself-sufficiency.
1.6 LegislationTh is is a brief introduction to a small part of
the existingleg i s l a tion . Th e complex i ty o f the l eg i sl
a t ion a nd theindividual nature of older buildings make it
impossible toprovide detai led guidance here. Each bui lding must
beassessed individually. If the re are any doubts or concerns,a d v
ic e m u s t b e s o u g h t f ro m t h e l o ca l a u t h o r i t
yconservation officer and the building control officer: i tc a n b
e h e l p f u l t o h a v e a n e a r l y m e e t i n g w i t h t h
e mtogether. Where the building is of special interest (e.g.
ascheduled ancient monument or a building with Grade Io r 11 l is t
ing) , the His tor ic B ui ldings Inspectorate mayalso need to be
consulted.1.6.1 Background nformationBuildings in the U K have
three principal forms of statu-tory protection:( a ) scheduled
ancient monumentsb ) listed building s
( c ) buildings situated in con servation areas.Th ere are many
reasons why older buildings require thisprotection, e.g. type,
method of construction, style, specialstructural o r aesthetic
features or finishes, and associationswith fam ous people, historic
even ts or their designers andbui lders . Each b ui lding has i t s
own par t icular qual i t iestha t c on t r ibu te to i t s spec ia
l in t e r es t . Th e con t ro l l ingl e g is l at i on d i f fe
r s f ro m c o u n t r y t o c o u n t r y a n d a n ya s s es s m
e n t o f a p r o t ec t e d b u i l d i n g o r a n y a d v i c e
o r
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4 Guide t o b uild ing services for historic building
srecommendations made will need to reflect the relevantcontrols in
force locally.1.6.2 Scheduled ancient monumentsAncient monum ents
are pr imari ly protec ted under th eAncient Monuments and
Archaeological Areas Act 1979and are not subject to th e Building
Regulations. T hey aremostly structures (e.g. ruins), although a
few buildingsor parts or buildings re scheduled. Th e num ber
ofscheduled monuments is small, so they will not often
beencountered. Note that scheduled monument consent isrequired for
almost ANY work to a scheduled monum entncluding repair. If work is
contemplated, the HistoricBuild ings Inspectora te must be
approached for advicebefore anything at all is done.1.6.3 Listed
buildingsIn England and Wales , l is ted bui ld ings are protec
tedp r i m a r i ly u n d e r t h e P l a n n i n g ( L i s t e d B
u i l d i n g s a n dConservation Areas) Act 1990. The equivalent
legislationi n S c o tl a nd i s t h e P l a n n i n g ( L i s t e
d B u i l d in g s a n dConservation Areas) (Scotland) Act 1997 and
i n Irela nd isthe Planning (NI) Order 1991. Listed buildings are
gradedto show their relative architectural or historic interest.
InEngland and W ales the grades are:Grade I: buildings of
outstanding historic or architecturalinterestGrade II*:
particularly important buildingsGrade 11: of special interest,
warranting every effort topreserve them.I n Sco t land and Nor the
rn I re land , gene ra l ly s imi la rgrades A, B a nd C are
used.Works that affect the character of a listed building
requirelisted building consent. Consent is not normally requiredfor
like-for-like repairs. Listed building controls apply toworks, both
externally and internally, that would affect abui ld ings specia l
in teres t , whether o r not the fea tureconcerned is specifically
men tioned in th e list description.This effectively means that the
whole of the building islisted, including existing services,
fixtures and finishes.The listing of a building normally covers its
curtilage sooutbuildings may also be listed. Any work that affects
thecharacter of th e bui ld ing can only be carried out oncelisted
building consent has been obtained from the localplanning
authority. It is a crimina l offence to carry outworks without such
consent.Carrying out works without listed building consent canlead
to prosecution under the relevant legislation (seeabove). T h e
legislation c onta ins provisions for fines of&20 000 and/or
six months imprisonment. However, caselaw records fines of up to
&75OO0. 4)Planning Policy Guidance Note 15 PPG 15) 5 ) rovidesd
e t a i l e d a d v i c e a n d g u i d a n c e f o r t h o s e m a
k i n g o rconsider ing appl ica tions for l is ted bui ld ing
consent inEngland. Similar guidance exists for the remainder of
theUK. 6-8)
1.6.4 Conservation areasIn conservation areas, there is
generally a presumption infavour o f r e ta in ing bu i ld ings wh
ich make a pos i t ivecontribution to th e character o r appearance
of the area;a n d c o n s e n t i s r e q u i r e d t o t o t al l
y o r s u b s t a n t i a l l yd e m o l i s h a n y b u i l d i n
g , w h a t e v e r i t s q u a l i ty . M i n o rdevelopments are
controlled to ensure that alterations donot detrac t f rom the
conservat ion areas appearance:controlled alterations may,
depending on the individualconservat ion area , inc lude cer ta in
types of c ladding,inserting dormer windows and putting up
satellite dishesvisible from the street. Co nservation area status
alone doesnot provide the scope for stringent control, particularly
incomparison with scheduled monuments and listed build-ings.Fo r
dwelling houses in a conservation area, an Article 4Direction can
give increased legal protection. This willr emove pe rmi t ted deve
lopmen t r igh ts a f fec ting someaspec ts o f the ex te rna l
appea rance , typ ica l ly doors ,windows, roofs and frontages.
There may also be controlover adding external services such as gas
and drain pipes,extract grilles an d boilerherm ina1 flues,
especially to partsof the building visible from the street and
other publicplaces. Not all conservation areas have Article 4
direct-ions, but where they are in force they influence the extenta
n d n a t u r e o f a l t e r a t i o n s t h a t c a n b e m a d e
, e v e n t ounlisted buildings.1.6.5 Recommended approach for
buildings
protected by legislationDeterm ine whether the bui ld ing is pro
tec ted ornot.I f i t i s p ro tec ted , ob ta in a copy of the fo
rm a ldescription, e.g. the list description, to determinewhat the
special interest is. T he list descriptioncan usually be obtained
from th e local authority orthe Historic Buildings Inspectorate.M a
k e e a r l y c o n t a ct w i t h t h e l o ca l a u t h o r i t
yconservatio n officer to discuss ini tial proposalsan d to
identify areas where problems m ay arise.Identify what other
legislation will influence theproposed works, e.g. Health &
Safety at Work etcAct.For applications where consent is needed,
allows u f f ic i e n t t i m e f o r t h i s i n t h e p r o g r a
m m e ,including poten tial delays (this m ay add severalmon ths to
th e project).Obtain all the necessary consents and approvals
inwriting before carrying out any work. Only carryout th e work
authorised: if changes or additionalworks a re requ i red , no t i
fy the loca l au tho r i tyconservation officer (and the Historic
BuildingsInspectorate, if involved) imm ediately nothe ra p p l i c
a t i o n f o r c o n s e n t m a y b e n e c e s s a r y
.Unauthorised works could constitute a criminalact (see Section
1.6.3).Allow for periodic visits from the local authorityc o n s e
r v a t i o n o f f i c e r ( a n d i f a p p r o p r i a t e t h
eHistor ic Build ings Inspectora te) to inspect theworks in
progress.
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Pr ncipies 51.6.6 VATSome work to listed buildings or scheduled
monume ntsm a y b e z e ro - r a t e d fo r V A T . A t t h e t im
e o f w r i t i n g ,alterations are zero-rated, but repair and
maintenance isnot. Therefore, installing completely new services,
e.g. aheating system in a building wh ich had n one before, couldbe
eligible, while upgrading an existing system might beconsid ered a
repair, at least in part.Only approved work to a listed building or
scheduledmonument qualifies for zero-rating, i.e. where the workh a
s r e c e i v e d l i s t e d b u i l d i n g c o n s e n t o r i n
v o l v e ssubstantial reconstruction (this would normally
requirelisted building consent anyway). All appropriate planningand
listed building consents must be obtained before anywork is
undertaken. HM Customs and Excise wil l notsanction zero-rating for
consents granted retrospectively.
1.7 Building R egulatio nsAs the needs of society are constantly
changing, it is ab a s i c t e n e t o f l e g i s l a ti o n t h a
t i t s h o u l d n o t b eretrospective. It is therefore
contradictory to insist onpresent day standards (U-values, double
glazing etc.) forhistoric buildings. On the other hand, historic
buildingshave to meet mo dern needs if they are to be conserved
oradapted.
A p p r o v e d D o c u m e n t s Ll a n d L 2 o f t h e B u i l
d i n gRegulations(3) ecognise the special nature of
historicbuildings specifically. The precise wording of DocumentL 2
is as follows Approved Document L1 is similar):4.11 The need to
conserve the special characteristics of suchhistoric buildings
needs to be recognised: see BS 7913. In suchwork the aim should be
to improve energy efticiency where andto the extent that it is
practically possible, always provided tha tthe work does not
prejudice the character of the historic building,or increase the
risk o f long-term deterioration to the buildingfabric or fittings.
In arriving at an appropriate balance betweenhistoric building
conservation and energy conservation, it wouldbe appropriate to
take into account the advice of the localplanni ng authoritys
conservation ofticer.4.12 Particular issues relating to work in
historic buildings tha twarrant sympathetic treatment a nd where
advice fro m otherscould therefore be beneficial include:a )
restoring the historic character of a bui lding that had
beensubject to previou s inap propriate alteration, e.g.
replacementwindows, doors and rooflights;b ) rebuilding a forme r
historic build ing e.g. foll owin g a fire orfilling in a gap site
in a terrace);c ) making provisions enabling the fabric to breathe
to controlmoisture and potential long term decay problems: see
SPABInformation Sheet No 4 . 9 )
eed thermal and visuacomfort control of localtask they carry
out
from damp and condensation, carin changes in ventilation or
heating,use of inappropriate materials,or design conditions for
contentswhich dont suit building
Buildingcontents/artifacts
Needs awareness of effect ofemissions from building:coZemissions
from fossil fuelOzone depleting substancesLocal:Pollutants from
building products 1Pollutants in case of fire
&-- Need strict control over* environmental conditions:
1Figure 3A balancing act.
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6 Guide to buildinq services for historic buildingsThe
Regulations highlight some of the principal issuescovered in this
Guide. However, there is a danger that theparagraphs above may be
in terpre ted as not requir ingANY improvements. This is an
oversimplification: thereis no excuse for wasting opp ortunities
and doing nothing.Even i n t he m ost difficult cases, there is
usually a range ofth ings one can do to improve ene rgy e f f ic
iency , seeSection 1.10. Indeed, because the scope for
improvingsome aspects (e .g . fabr ic and window ins ula t ion)
mayoften be limited, it is particularly important to seize
thoseopportunities that do offer themselves, and to make thevery
most of them.On the other hand, pressure to im prove energy
efficiencycould expose traditional buildings not defined as
historicand with no s ta tu tory protec t ion to inappropria te
andunnecessary replacements. F or example, the appearance ofwindows
and doors is often a very important part of abu i ld ing ' s ( and
an a rea 's ) spec ia l cha rac te r . T o lo seserviceable fabric
and to replace it with materials with, atbest, dubious
environmental credentials is not sustainable.Every effort should be
made to retain serviceable fabricsince this will normally be more
cost effective and moreenv i ronmen ta l ly e ff ic ien t in the
longe r - te rm. S implemeasures such as repairing and upgrading
existing fabricand perhaps ins ta l l ing secondary g laz ing can
produceresul ts to match those of modern replacements . Suchmodern
replacements may both detract from a building'scha rac te r and be
incom pa t ib le wi th i t s pe r fo rmance .Wh ere rep lacemen ts
a re necessa ry a r t i cu la r ly o fwindows an d doors he
materials and design need verycareful thought (l O)
1.8 Design principlesT hi s Sec t ion h igh l igh ts som e o f
the p r inc ip le s to bef o ll o w e d d u r i n g w o r k o n h i
s t o r ic a n d s t r a d i t i o n a lbuildings. It is expanded
in Section 4.4.The principlescan be followed in any work to
historic or traditionalbuildings.T he following funda mental
principles are adapted fromthe list in The repair of historic
buildings: advice on principlesand methods.( ) Th ey are expanded
in Section 4.4:( i )( i i ) Minimise intervention.(iii) Avoid
unnecessary damage.( i v )
Understand the purpose of repair or alteration.
Se e k r e v e r s i b i l i t y a n d m i n i m i s e i r r e v
e r s i b l edamage.Plan ahead: Allow time to liaise with the
relevant officialson conservation an d buildin g contro l issues.
Allow forp rob lems wh ich a r i se when un fo reseen p rob lems a
reexposed du ring w ork on s i te . Ensure effec tive l ia
isonbetween all those involved in the project.Do not impose
standard solutions: The individual nature of,and value placed on,
many older buildings and their fabricmakes it imperative that
bespoke solutions are devised tofit the specific circumstances of
the individual building.Get the balance right: Balancing the needs
of the buildingfabr ic, th e occupants and the contents , while
meet ingdesired environmental criteria can be difficult (Figure
3).
In many cases, the robustness of a building is only testedby
making alterations, by which tim e it may be too late.Use only
materials that are compatible and consistent with theintended
performance of the building: I t c a n a l so b ed e t r i m e n t
a l t o t h e f a b r i c to i n t r o d u c e i n a p p r o p r i
a t esystems and performance regimes. If standard solutionsare
applied to highly individ ual buildings, fun dam entalproblems may
be ignored or symptoms may be t rea tedrather than causes. The
consequence can easily be fasterdeterioration of th e building.T he
consequences o f app ly ing inapprop ria te s tand a rds o l u t i
o n s t o h i s t o r i c b u i l d i n g s c a n b e s e r io u s
. I npa r t i cu la r , the requ i remen ts o f museum exh ib i t s
andcollections can be incompatible with those of the
buildinghousing them.(12J3)
Summary of design principlesappropriate for work in
olderbuildings
U n d e r s t a n d t h e b u i l d i n g b e f or e m a k i n g
a n ychanges: its architectural or historical significance,its
structural performance and the patterns of airand moisture
movement.Do not rely on standard solutions to what will behighly
individual circumstances: devise bespokes o l u t i o n s w h i c h
s u i t t h e b u i l d i n g ' s s p e c ia
lcharacteristics.Determine w hether the building can accommodatethe
proposed alterations.Be sure you know what statutory protection
thebuild ing has a nd what consents are required tocarry out any
proposed work.Only do work that is necessary: historic buildingsand
the i r f ab r ic a re a f in i te and i r rep laceab leresource;
once lost they can never be replaced.Make a presumption against
damage to or loss ofhistoric fabric. Where works are necessary, aim
tominimise th e amount of intervention.Design new services which
have long lives an d caneasily be maintained and serviced. This
will helpto minimise the building's exposure to
potentialdisturbance.S e r v i ce s s h o u l d b e i n s t a l l e
d w i t h a s l i t t l edisrup tion as possible to the historic
fabricNew work should aim to be reversible, allowingt h e f a b r i
c t o r e v e r t t o i t s f o r m e r s t a t e w h e r
eappropriate.S e r v i ce s s h o u l d b e s y m p a t h e t i c t
o t h e i rsurroundings . They should not detrac t from thea p p e
a r a n c e o f t h e b u i l d i n g , i t s f a b r i c o r i t
scontents.A l t e r a t i o n s s h o u l d b e c o m p a t i b l e
w i t h t h ebuilding, rather than working against it.Use existing
spaces and voids rather than cuttingi n n e w ( b u t e n s u r e t
h a t y o u u n d e r s t a n d t h epurpose of these voids first;
for example, they maybe part of the original ventilation
system).
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Building services 7
m) In troduce serv ices tha t minimise the impact onthe
environment by being energy-efficient, andwhere possib le maximise
the use of renewableenergy sources.
1.10 Simple nonintrusive ways o fimproving energy efficiency
Th ere are simple ways of improving the energy efficiencyof
nearly all buildings, includin g:
installing better controlsselecting efficient plant, especially
boilers
specifying long-life efficient light sourceslim iting excessive
air infiltration (but dont overdoit ee Section 3.3).ensu ring
better managem ent of existing systemskeeping proper records ,
readi ly accessib le (butwith safely archived copies)undertaking
effective preventive maintenance
Most of these can be applied without adversely affectingfabric
and contents, even in buildings which cannot beal tered physica l
ly because of the ir s ignif icance , the ircondition or their
sensitivity. It is very seldom th at thereis absolutely no thi ng
you can do.
2 Building services2.1 Modern expectations and
standards o f servicePeoples expectations of heating, lighting,
transportationand electrical services in buildings are much higher
nowthan in th e pas t . In t e rms o f amen i ty , wha t was
oncecommonplace can also be unacceptable.
Most h is tor ic bui ld ings have changed s ince they werebuil t
. A change can trigger vast a lterations in services:lighting,
heating, perhaps some airconditioning, cabling,power poin ts , te
lephones and data l inks , p lus modernstandards of fire detection
and protection. The followingservices are most likely to be
expected today. Historicbuildings cannot always accommodate them
all:h e a t i n g b o i le r , f u e l s t o r e / s u p p l y w i
t h m e t e r sa nd or delivery arrangementschimneys, flues and
flue terminalsheating emitters and controls
sanitary accomm odationh o t a n d c o l d w a t e r p r o v i s
i o n , s to r a g e, a n ddistribution
electrical circuits for small power and ligh tingpower, data and
telephone lin ksfire detection and alarms and emergency
escapelighting enerally man datory for peoples safetyand the
preservation of the buildingfire protection schemes such as
sprinklersmechanical vent i la t ion , som etimes with supplyand
extract ductworkdrainage, both rainwater and foult r a n s p o r t
a t i o n a n d d i s a b l e d a c c es s i f ts ,escalators, ram
pspublic-address and hearing-loop provisionc o o l in g a n d a i r
c o n d i t i o n i n g , i n c l u d i n g h e a trejectioncontrol
systemssecurity systemslightn ing protection.
Building services are normally designed to suit people
andprocesses. In historic buildings, it is very important
toconsider the building itself. For example, one may wish toc o n t
r o l t h e h e a t i n g t o r e g u l a t e r e l a ti v e h u m
i d i t y( c o n s e r v a t i o n h e a t in g , s e e Se c t i o
n 3.5 , a n d n o tnecessarily the comfort of the users. Similarly,
fire safetysystems may be designed to th e higher property
standard,not merely to give adequate time to evacuate people but
tohelp protect th e building (see case study 25).A good solution
will strike a balance between the needs ofthe building, the
occupants and the global environment.Inevitably, some compromises
will often have to be made,b u t g r e a t c a re i s n ee d e d t
o e n s u r e t h a t t h e s e d o n o td e v a l u e t h e a i m
s o f t h e p r o j e c t : m e e t i n g c l i e n trequirements
while protecting the fabric and making thebuilding more energy
efficient.
2.2 Increasing sustainability2.2.1 Reducing annual carbon
dioxideemissions
Figure 4 These external toilets to a Grade I1 isted public house
areconsidered basic today, and can discourage customers. However,
th echaracter and special interest of a building can be threatened
by suchdemands for change, which may not always be easy to
accommodate.
Building services often use large amounts of fossil fuel
tomaintain the conditions required. This has a detrimentalimpact on
the a tmosphere , owing to th e re lease of theLi
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8 Guideto building services for historic buildings
greenhouse gas carbon dioxide, acid gases including theoxides of
sulphur and nitrogen and other pollutants. i n a n y q u a n t i t
y ) c a n b e c o n s i d e r a b l y m o r epolluting than using
fossil fuels.Pollution can be reduced by: Renewable energy sources
(as used in case studies12 and 13) have close to zero CO,
emissions. This
using less fuel; is obvious. for direct generators suLh as w
indpower,hydro-electric generation etc. It also applies whenburning
biomass such as straw and woodchipapar t f rom any foss i l fuel
used in cul t iva t ion ,h a r v es t in g , t r a n s p o r t a n
d d r y i n g . T h e c a r b o ndioxide produced by burning the
woodchips istaken back up in t he cycle if the coppice sourcingthe
woodchips is allowed to re-grow. Effectively,one has net zero CO,
emiss ions , where energyf r o m t h e s u n i s c o l l e c t e d
a n d h a r v e s t e d a s astorable fuel source with m inim al
fossil fuel use.
using cleaner fuels, i.e. those with lower, or evenzero, carbon
dioxide em issions;using cleaner an d m ore efficient
appliances;reducing the design load, for example by
addinginsulation (see Section 3.2); andcontrolling and managing
systems effectively.
In older buildings, it is not always easy (and sometimesnot even
desirable) to reduce the requirements for heatingenergy by adding
insulation and cutting air infiltration (asdiscussed in Section 3).
To help make up for this, one can2.2.2 Reducing pol lut ion of the
externalenvironment
nearly a lways use the most eff ic ient p lant a nd co ntro
lsystems, and maintain and manage them well. Other
combustion-related pollutants can also damage theenvironment , the
bui ld ing fabr ic and peoples heal th .Figure shows t h e of ca
rbon di ox id e Oxides of sulp hur and nitrogen (including acid
rain) alsodamage trees, aquatic life, and the fabric of buildings,
asemissions associated with 1 kilowatt-hour (kW h) of energy
illustrated in F igure 6 .delivered to a building in th e form of
different fuels. Th efollowing conclusions can be reached.
2.2.3Gaseous fuels emit less CO, than liquid or solidfuels. T hi s
reflects the fuels carbon/hyd rogen r atioImproving health and the
internalenvironment
he lighter the fuel, the more hydiogen. Henceless of the energy
is locked up in carbon in naturalgas (mostly methane, CH,) than in
the liquefiedpetro leum gas propa ne (C,H,), an d so on for
theheavier fuels.On average, UK mains electricity produces
muchlower CO, emissions per delivered unit now thani t d id in 1990
and be fo re wing to g rea te re f f i c ie n c y , a g r e a t e r
p r o p o r t i o n o f g a s - f i r e dgeneration and higher
availability of nuclear plant.However , bu rn ing foss il fue l s a
t a conve rs ionefficiency of between 30% and 60% still accountsfor
about 70 of UK production. Therefore, to useelectricity directly
for heating (and for hot water
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - - - - - - _ _ -
enewables
NuclearSolar heat
Wood - sustainableElectricity from wind, waterN atu ra l g a s
p
Propane (egDomestic h eating oi l
Heavy oilWood -deforestation
CoalAnthracite
CokeElectricity (UK 1998 average)Electricity (UK 1980
average)Electricity from coal
Fossil based ornon renewables
0 0.5 1kg CO2 per k Wh
Figure 5 Carbon dioxide produced by different energy sources in
theUK
Bui ld ing se rv ices a re in tended to improve the
indoorenvironment, but they can introduce hazards, directly
orindirec t ly . T he effec ts of d ir ty , unhygie nic p lant a
ndductwork and of leakage of combustion fumes are nowwell known,
and careful design is essential, followed byc a r e f u l m a i n t
e n a n c e o f c l e a n l i n e s s , s a f e t y a n
dperformance. The combined effects of heating, ventilationand
insulation on the environm enta l equi l ibr ium of thebuild ing
are a lso important . Damp condit ions can not
Figure 6 A carved figure on a Grade 11* listed church. The
deteriorationof this fine-gra ined stone has been accelerated by
pollution. Recentresearch(14)has shown that the well know n
degradation of limestones bythe oxides of sulphur (mostly emitted
to the atmosphere during burningof coal and heavy oil) is much
accelerated by the oxides of nitrogen(mostly from traffic but also
emitted by boilers); so the expectedreductions in stone decay with
falling sulphur dioxide levels have nothappened, particularly in
and downw ind of urban areas
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Buildinq services 9only cause building decay but can also affect
occupanthealth both directly or by the products of
biodeterioration,e.g. fungi which colonise the lungs or moulds with
toxicspores. The materials used in the building
servicesinstallation itself also need examination. The
combinationof new, chemically complex and sometimes
unstable,building products with changes in lifestyle (e.g.
lessventilation and more time spent indoors) have increasedthe
exposure of people to potentially toxic materials orbyproducts.
Although the long-term effects of manyproducts are not yet
quantified, it is responsible to assessthe potential impact of all
products on the health ofoccupants.(15)2.2.4 Using more sustainable
materialsMaterials should be selected carefully and specified
toensure that they cause as little pollution as possiblethroughout
their life: during extraction; in manufacture;during construction
or installation; when performingtheir intended use; and when
finally removed for re-use,recycling or disposal. Increasingly, the
specifier must beaware of the life cost and impact of each material
specified.This embraces the environmental and health
implicationsthroughout i ts life and use including toxicity and
thepresence of dioxins and volatile organic compounds(VOCs). Only
if a careful holistic cradle-to- graveapproach to design is adopted
will the risks to health andthe envi ronment be reduced and t ruly
sustainablesolutions formulated.Views on specific materials can
change rapidly. Forexample, many countries are becoming concerned
aboutthe use of polyvinylchloride, owing to its perceived threatsto
environment and health articularly duringmanufacture and if it is
burned at the end of its life cycle.Its use needs to be reassessed
in t he light of theseconcerns, and alternatives specified where
possible.2.2.5 Efficient plantUpgrading the energy efficiency of
the fabric of a historicbuilding can often be difficult, so it
becomes particularlyimportant to make the installed plant and
systems asefficient as possible, even if they cost more. The
mainareas of concern are boiler and aircondi tioning
plantefficiency and control, and any electric motors which runfor
extended periods.Fossil fuel boilers should be at the top of the
availableefficiency range. This will usually mean
condensingboilers; and these have been used successfully in many
ofthe case studies. However, condensing boilers create amuch larger
visible plume of water vapour at the flueterminal or chimney top
than do ordinary boilers. Fluesmust therefore discharge away from
areas susceptible to abuild up of moisture (as in case study
1).Where this isimpossible (e.g. in a small courtyard), a
noncondensingmodel may be necessary. It is also necessary to
provide adrain for the products of condensation which can
beacidic.It is important to compare boiler efficiency not just at
fulloutput but across the likely performing range, e.g at highand
low firing. For domestic sized boilers, seasonalefficiency can be
checked through the Sedbuk rating (seewww.boi1ers.org.uk). Boilers
in category A would be
appropriate, especially in buildings where insulationmeasures
are not practicable.Airconditioning plant can have a major physical
impactand use a lot of energy. It should only be installed where
itis proven to be essential to the operation of the
building.Systems which default to on unnecessarily and
wastefullyare all-too-common in buildings today, so controls
shouldbe designed and commissioned to ensure that plant is
onlyoperated when and to the extent it is actually needed.When
selecting electric motors, calculate how much theywill run. If this
is more than 1500 hours per year, assessthe economics of installing
either high-efficiency or DCtypes.Combined heat and power (CHP) is
a way of maximisingthe amount of energy from a fuel, so reducing
carbondioxide emissions. CHP both produces power (usually
aselectricity, but sometimes as mechanical power), andmakes
available much of the otherwise wasted heat fromthis process. This
can be used to provide heating or hotwater or to run equipment, eg
absorption chillers. Takecare that there are sufficient base loads
of both heat andpower to make the CHP plant run for enough time
toproduce a reasonable economic case for investment(typically at
least 3500 hours per year, as often occurs inhospitals and large
hotels). The big mistakes often madeare to oversize the plant, or
to assume that the heat isfree. CHP is very unlikely to be viable
without aguaranteed year-round use for the heat.
2.2.6 Low water useWhere new water appliances are installed,
consider water-efficient types, e.g. low-flush (less than 6 litres)
and dual-flush (two-button) WCs, hand basins with automatic
spraytaps using less than 2 l/min, low water showers (less than
8l/min), and waterless WCs and urinals. Equipment foundin older
buildings can often be very extravagant, but itsperformance can
sometimes be improved considerably,e.g. by fitting flow restrictors
to taps. New equipmentdesigned to look traditional can also be very
wasteful:take care that your choice properly balances
therequirements of appearance and water economy.Convoluted
hot-water supply and distribution systems canwaste a lot of heat,
particularly if uninsulated and in largerbuildings. Seek
opportunities to rationalise and improvethem. Sometimes, a
decentralised system with local gas oreven electric water heaters
will be more economical andenergy efficient.Water leaks are a
serious threat, with risks ranging frommajor flooding to slow drips
causing staining andeventually perhaps dry rot. Problems can be
reduced bycareful routing, good specification using
burst-resistantmaterials, good workmanship, inspection and testing,
andeffective frost protection. In sensitive situations, one
caninstall safety guttering or electronic leak detectionsystems; or
or major leaks utomatic alarms andshut-offs. Sometimes, it will be
best to keep water out ofan area altogether (e.g. upstairs in case
study 8).
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10 Guide to bui ld in g services f o r historic bui ld ings
2.2.5 Temporary servicesT e m p o r a r y s e r v ic e s , p a r
t i c u l a r l y t h o s e u se d d u r i n gconstruction work
(e.g. transformers, cables, lighting,heaters and dehumidifiers),
can create hazards of theirown. People may bring in their normal
equipment or useit inappropriately, w ithout th inkin g about th e
sensitivityof the building. Risks include not only fire, electric
shockand o i l sp i l ls from genera tors , but a lso damage to th
eh i s t o r i c f a b r i c b y t o o v i g o r o u s u s e o f h
e a t e r s a n ddehumidifiers. Rapid decreases in humidity can
causeshrinkage and cracking, particularly in timber products.W here
temporary heaters an d dehum idif iers are used ,vulnerable con
tents will need to be taken int o safe storage,and vulnerable
building elements protected. Alternatively,these temporary systems
may need to be operated underthe sup ervision of a conservator.On
the other hand, dehumidifiers can often be ineffectivebecause the
space to be dried is not properly sealed, withdoors , f lues and
holes remaining open. S ince water iscollected, people think that
the dehumidifier is do ing itsj o b ; w h e r e a s m o s t o f t h
e m o i s t u r e h a s c o m e f r o melsewhere ften directly from
t he outdoo r air.
2.3 The valu e of his tor ic bu i ld ingservices
Before any changes to a bui ld i ng are considered , i t
isessential to assess the existing services (especially an
yoriginal features) and understand how they work and howthe
building contributes to knowledge of th e developmentof services
through the ages. The arrangements can bevery interesting and
sophisticated, as in case studies 26and 27. If a building is
listed, remember that the listingprotects everything - ncluding the
services nd that itis a criminal act to change anything without
permission.T he services may form an important part of th e
building'shistory, archaeology, character or appearance, or may
beimpor tan t in the i r own r igh t . Be fo re cons ide r ing
theremoval of any items, it is essential to confirm whetherapproval
is needed. Case study 15 illustrates a case whereEnglish Heritage
insisted that a derelict original heatingsystem being restored,
while in case studies 16 and 24opportunities were taken to remove
inappropriate servicesan d to reinstate original features.
Figure 7 A redundant horticultural boiler, previo usly used to
heat a green house, in the garden of a Grade I1 isted building. The
boiler house andboiler were not specifically listed but, since they
are within the curtilage of a listed build ing, they are equally
protected as curtilage structures . Listedbuildin g consen t was
required to remove the boiler. Its asbesto s claddin g was breaking
down, creating a seriou s health hazard. Before the boil er
wasremoved, all the asbestos was carefully stripped by a specialist
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Building services 11
2.4 Re-using existing servicesExisting building services plant
must be assessed regularlyto determine whether it is working
properly, its efficiency,safe ty, l i fe expectancy and any r isk s
i t poses . Ideally ,provided that it remains safe and reasonably
efficient,building services equipment should remain in active
usefor as long as possible. Even when its useful life is over,one
may want to retain it in situ for its aesthetic, historic
orarchaeological interest ither as a whole or in part asevidence of
how th e building was once serviced.Ma ny types of serv ices, par t
icular ly heat emit te rs andlighting equipment, are often suitable
for re-use and addconsiderably to the character of a building. Too
often, thisis only appreciated after they have been taken out Suche
q u i p m e n t m u s t b e c h e c k e d f u l ly a n d u p g r a
d e d a snecessary. It is often possible to restore old light
switchesand luminaires and make them safe. Old radiators
willrequire cleaning and pressure-testing, and the joints andvalves
should b e checked, eased and renewed as necessary.If pipework is
to be re-used, the water should be testedand external and in ternal
inspect ions of the p ipeworkshould be carr ied out . Chemical c
leaning may a lso berequired. Before it is recommissioned, the
entire systems h o u l d b e f u l l y p r e s s u re t e s t e d i
n o p e r a t io n , a n dthoroughly checked for leaks and other
faults.Assess health risks associated with use of the
existingbuilding services equipment to determine how to handlethem
and whether th e p lant can be re-used . Dangerousand
health-threatening services should not, of course, beretained in
use: the health and safety of the occupantsmust have priority. D
angerous electrical installations andequipment mu st always be made
safe immediately. Fi re isone of the greatest threats to the fabric
and c ontents ofhistoric buildings.(16>7TAKE GR EAT CARE:
Asbestos was very widely used tolag boi lers and p ipework. I f i t
is encountered or eventhought to exist, leave it alone and seek
specialist advice(owing to th e severe health risks it is better to
be safe thansorry). Licensed contractors must be employed to
removean d dispose of any asbestos.
2.5 Criteria for the selection of newbuilding services in
historicbuildings
First ask the question: are new building services required
atall? Exposing a historic building to unnecessary changeincreases
the potential for irreparable damage. If you thendecide to proceed,
t he new or upgraded services must be:compatible with the
building;compatible w ith th e performance of the fabric
(asdiscussed in Section 3); ande f fi c ie n t, t o m i n i m i s e
t h e i m p a c t o n t h eenvironment.
W h e r e e x is t i n g b u i l d i n g s e r v ic e s a r e r
e ta i n e d , i t i sessential to ensure that the new services are
integrateds u c c e s s f u l l y i n a m a n n e r t h a t d o e s
n o t c o m p r o m i s einstallation, performance, use,
efficiency, maintenance orlife expectancy. For example, old heating
systems often
came up to temperature s lowly and the thermal shockfrom th e
faster response of modern boiler plant m ight giver i s e t o l e a
k s i n e x i s t i n g p i p e w o r k . S i m i l a r l y, m o r
ecompac t , h ighe r - re s i s tance modern te rmina l dev
icesrequiring high water pressures may not mix on the samecircuit
as histo ric radiators designed for gravity flow.
2.6
Finding suita
Installing new building servicesand upgrading existing onesde
routes for DiDes. cables and ductwor IA *n e e d s c a r e f u l t
h o u g h t a n d i m a g i n a t i o n t o m i n i m i s
einterventions, and to avoid other problems for the fabricor , a t
wors t , s t ructura l s tabi l i ty . In mod ern bui ld ings
,build ing services are often n ot designed o r specified indetail,
much being left to the discretion of the contractor.F o r e x a m p
le , t h e c a b l e r u n s b e t w e e n s w i t c h e s a n
dlumina i re s a re ve ry se ldom shown . In many h i s to r ic
buildings, such detailed design is essential to improveplanning
and appearance, and to minimise unnecessaryphysical intervention. T
he extra investigations, drawings,specifications and collaboration
on site will inevitably addto the time and costs, as will the
necessary consultationand approval processes for statutorily
protected buildings.However, th is work is absolutely
essential.
2.6.1 Notchin g, cut t in g and chasingWo rk to accom modate
services can seriously affect thecondit ion , s t ructura l
performance and preservat ion ofo lde r bu i ld ings , a nd sho u
ld on ly be ca r r ied ou t a f te rappropria te specia l is t
advice has been soug ht . A goodstarti ng poin t is to aim not to
notch or cut any timbers,chase an y walls, or make holes in
important places.Cu t t ing and chas ing des t roys h i s to r ic f
ab r ic , may beunsightly and can seriously weaken floors and old
wallsand partitions. Floorboards a nd wall finishes of
historic,architectural or archaeological interest could be
damagedirreparably or even lost. In the end, som e kin d of
physicali n t e r v e n t i o n s w i ll n e a r l y a l w a ys b e
n e c e s sa r y , b u tapplication of imagination in seeking to
minimise themcan be rewarding, as shown in case stud y 19.W here t
he cov er ing surfaces (e .g . f loorbo ards) can beremoved safely
and carefully (with the approval of ther e l e v a n t o f f i ci a
ls ) , o p e n i n g - u p o f t e n r e ve a ls h i d d e no p p o
r t u n i t i e s f o r s e rv i c e r u n s ( a n d s o m e t i m
e s e v e nequipment, as in case study 24), together with
unexpectedobstacles (as in case study 4).A good set of drawings
alsoreveals possibilities for vertical conn ections (as for the
liftsin case s tudy 4). Thick walls may a lso conta in usefulvoids,
particularly in Victorian and Edwardian buildings,e.g. as part of
an earlier ventilation system (see case studies26 and 27).O p e n i
n g - u p c a n a l s o r e v e a l h o r r o r s , e . g . d e c a
y ,unexpected obstacles and structure irresponsibly cut awayby
those installing previous build ing services
installations.Strengthening will then be required. Ways to
strengthenweakened f loor t imbers , for example by using fo ld
ingwedges or iron plates are shown in BS 5268.(18)
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12 Guide to building services fo r historic buildingsCentre of
Centre ofbealing bearingSpan
II I-1- -1-I IDepth of notch Ino t greater I
IIII
I Depth Dt IU II
Notches shouldbe in this zone IIII I-1 -
I-Span 5 .- Holes should ..:be located in jthis zone, and
drilled at theneutral axis I
Maximum Not less than Idiameter three diameters jof holes apart
(centre= D/4 to centre)
Folding wedgesFigure 8 Advice on maxim um dim ensions and
position s for holes ands grooves in joints, and on restoring
compressive strength to timb ers weakenedby ins erting central h
eating o r other service pipes(19)2.6.2 Install ing service runsTh
e f i r st s tage is to minimise th e am ount of pipework,c a b l i
n g a n d d u c t i n g ne e d e d, t o g e t h e r w i t h a n yi
n t e r v e n t i o n t o t h e e x i s t i n g f a br ic . C a s e
s t u d y 2 4i l lus trates why fan-coi l a i r cond i t ioning was
chosen inpreference to an al l -ai r sys tem at th e Royal Society
ofChemis t ry . T he bu i ld ing s e rv ices eng ineer m us t w
orkc l o se l y w i t h t h e a r c h i t e c t o r s u rv e y o r
( a n d t h e n t h ebuilder) to m inimise, and where possible
avoid, situationsthat cause physical damage, surface damage or
removal ofany part of the structure and fabric. Even after a
carefulsurvey, specification and drawings, it is good practice
toagree and mark out on site exactly where everything is to
Figure 9 Exposed pipework in a cellar of a Grade I1 isted
building. Thepipework runs rou nd a principal structural floor beam
rather th ancutting through the timber, i l lustrating the fundamen
tal principle thatthe services should be adapted to suit the
building and not vice-versa.Th is arrangement has minimised the
disturbance to th e historic fabric,prevented any stru ctural
damage, provided flexibility for futu re work andreduced time spent
cutting through timbers
go; and also to confirm the types of holes that are to bem a d e
a n d t h e f i x i n g s a n d b r a c k e ts t o b e u s e d . A
n yalterations to the drawn and agreed scheme should also
beconfirmed o n site before any physical work commences.2.6.3
Exposed servicesUse of exposed pipes, cableways and sometimes ducts
canminim ise the am ou nt of physical damage and interventionto
historic fabric. However, appearance is often param ounthat will
the services look like, and do they suit ther o o m i n q u e s t i
o n ? I n a f o r m a l ro o m w i t h v e r y f i n edetailing,
exposed runs are unlikely to be appropriate asthey would detract
from the original attention to detailand geometryUnoccupied areas,
att ic spaces, cellars , roof spaces andoth er areas where
appearance or presentation is less of anissue create good oppo
rtunities for exposed service runsand for less concern about thei r
appearance, though aclean, tidy professional job is t he min imu m
accep tab lestandard anywhere. Exposing services can also be
morereversible and improve access for inspection, alterationand
main tenan ce nd eventual removal and renewal.Exposed pipework and
ductwork may, of course, need tobe insulated, an d frost-protection
strategies must be takenvery seriously. For example, what should be
the designstrategy for a building which could be empty and
difficultto reach du ring a long cold period, as in case stud y
13.Wh ere cab les a re ru n exposed , they mus t be ca re fu llyp o
s i t io n e d , s p e c i f i e d o r p r o t e c t e d t o m i n
i m i s e t h e i rvu lnerab i l i ty to phys ica l damage . Cab l
ing in h i s to r i cb u i l d i n g s m a y a l so n e e d t o e x
ce e d m i n i m u m r e -qu i r ement s , i n o rder to r educe f
i r e r isks ; and minera linsulated cables (MIC) o r othe r
specialist cable types maybe appropriate. Although specialist
cabling can be more
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Build ing services 13expensive, it has th e benefit of minim
ising the use of poly-vinylchloride (see Section 2.2.4), can last
longer and mayneed fewer fixings and supports.Where installation of
cable runs is likely to be extremelydifficult or damaging, radio
and signal receptive systemscan be considered ee case studies 19
and 25. Theselook promising , but the ir long-term performance
andtheir potential influence on health are currently
unknown.Remember that radio devices in inaccess ib le locat
ionswithout mains supplies still need regular access to changethe
batteries ypically every few years, but sometimesmore
frequently.2.6.4 Concealed pipeworkOlder buildin gs often have
voids and other spaces that canbe used to conceal pipework and oth
er services and tolimit any damage to the historic fabric. Th ese
include:
behin d panelling;
und er floors and between joists;in ceiling an d roof void
spaces;
in th e voids inside stud walls;u p r e d u n d a n t c h i m n
e y s a n d v e n t i l a t i o n f l ue s(these ventilation flues
may also prove useful fortheir or ig inal purpose , perhaps with
some fan-assistance);along the tops of wide cornices;along redund
ant service routes; andopportunity for concealment.w h e r e r e p
a i r s o r a l t e r a t i o n s p r o v i d e a n
Pulsed radar and other techniques may be used to locatevoids in
solid walls and floors nondestructively.Concealed routes have some
limitations:
Not a l l of them (e .g . ch imneys and vent i la t ionflues)
are accessible for inspection.Hidden leaks can go unnoticed for
long periods,and could trigger serious decay.Fabric can be damaged
by opening-up to find theconcealed voids, or if invisible leakage
causes asubsequent damp or decay problem.
It is essential tha t any services concealed be hin d fabric
befully recorded and tested before they are enclosed and
thedecorative finishes applied, particularly pipework
thatdistributes water. Testing will provide some confidencethat
there are no leaks that might cause decay and requireopening-up
later. Similarly, frost protection systems thatcover a l l the bui
ld ing are essent ial where p iped waterservices are present.2.6.5
Integration of pipework in timber
floorsLif t ing and protecting historic timber floors: T he g
rea tes topportun ity to improve services arises when m ajor
repairs,refurbishment, alterations, extensions or changes in useare
taking place. However, the floorboards in many olderbuildings are
of historic interest and it is undesirable to
renew them. It is sometimes wise to avoid even liftingfloor
boards, particularly old wide boards that have notbeen disturbed
before.(*O)SPAB Information Sheet I ? *) gives guidance on
handlingf l o o r b o a r d s . T o r e d u c e a v o i d a b le a
n d u n n e c e s s a r ydamage:
Ident ify and label a l l f loorboards indiv idual lybefore any
work starts.D r a w a p l a n s h o w i n g t h e p o s i t i o n s
o f a l l t h eboards.Lift the floorboards carefully.Make su re
that all lifted boards are stored safely ina n a r e a w i t h a p
p r o p r i a t e e n v i r o n m e n t a lconditions.P r o v i d e
p r o t e c t i o n t o t h e e x p o s e d a r e a s t opreventing
people or tools from falling throughand causing injury or damaging
historic ceilingsand finishes.P r o v i d e s af e w o r k a n d s
t o r a g e a r ea s w i t htemporary boarding.When the
installation work is complete, re-fix thef loorboards in the ir or
ig inal posi t ions . Do notreplace any boards unless repair is
impossible.When re-fixing, take great care not to punctureunderlyin
g cables or pipework w ith secur ing nails.
W h e n i t i s e s s e n t i a l t o l i f t f lo o rs , d o n
o t m i s s t h eo p p o r t u n i t y t o r a t i o n a l i s e t
h e s e rv i ce s , t o p r o v i d ec o m p r e h e n s i v e i n
s t a l l a t i o n d e t a i l s a n d t o p r o v i d eadditional
conduit runs to facilitate future installation andupgrading. T o
minim ise fu ture d is turbance , i t is goodp r a c t i c e t o p
r o v i d e a c c e s s c o v e r s f o r i n s p e c t i o n
,maintenance and future upgrading. T hey should normallybe
screw-fixed for ease of access and to prevent damage tothe covers
or the services undern eath when re-fixing. T helocation of access
points should be noted on drawings forfuture
identification.Planning ahead will reduce the levels of disturbance
andintervention and be cost-effective in the long term. Care-
* .Figure 10 A redundant flue being used as a pipe route. New
timberwainscoting hides electrical wiring
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14 Guide to bu ildi ng services for historic buildingsf u l p l
a n n i n g a n d p r o g r a m m i n g w i ll m a x i m i s e t h
epotent ia l of any opportuni t ies crea ted . T he ear l ier tha
tconsu ltants and the workforce are aware of what is needed,the
more likely it is that they will be able to allow for it inthe
pre-contract documentation. For example, specificat-i o n o f r e p
a i r w o r k s w i l l n e e d a n a l l o w a n ce f o r t h
eprincipal contractor to be in attendance on the buildingservices
contractor ho may be a subcontractor on theproject. T he cost and
pro gramm ing implications for theprincipal contractor would need
to be taken into accounta t the t ende r ing s tage . Th e c l ien
t wi ll no t app rec ia teaddition al costs that could easily have
been foreseen. If thework is carefully planned, many of the
services routes canbe pre-assigned and the necessary holes made
carefully inadvance.Assessment of exposed fabric: Once floorboards
etc. havebeen lifted and the structure, voids and existing
servicerun s a re exposed , make a fu l l and de ta i led su rvey .
Ifnecessary, re-assess the design proposals in light of thisnew
information, and decide whether any major changesare required.
Always keep an open mind about what willbe found, and allow enough
time to resolve the problemsand exploit opportunities.
IWARNING: Consultants and contractors tendering forwork in older
and more complex buildings must remem-ber that complications will
often be exposed by opening-up work.O n c e t h e fl o o r h a s b
e e n o p e n e d u p , t h e s t r u c t u r a lcondition of the
timbers and exposed walls needs to bed e t e rm i n e d . S t r e n
g t h e n i n g m a y b e r e q u i re d . W h e r eproblems of
decay or deta i l ing br ing in to quest ion th es t ruc tu ra l
capab i l i t i e s o f the f loo r t imbers and the i rbearings
with the walls, the advice should be sought of as tructura l
engineer conversant with h is tor ic bui ld ings .The structural
engineer (and where appropriate the buil-ding archaeologist and the
historic buildings consultant)should also be asked to comment on
the appropriatenessand compa t ib i l i ty o f any p roposed a l te
ra t ions . I f anytimbers are to be notched, it is important to
assess notonly their stren gth but also the part they play in the
widerstructural system, especially in framed structures wherethere
is an inter-relationship between individual timbersso that to
weaken on e timber can pass loads onto another.
Figure 1 Opening-up work will also reveal former building
servicesroutes, and som etim es several previous generati ons of
systems. Th isphotograph shows an old lead pipe (which may or m ay
not still be i n use)and a redu ndant copper one which had been cu
t off many years earlier
Figure 12 In this photograph, floorboards have been lifted to
expose therema ins of another, older floor below. Th is is itself
of historic int erestand w ill add to the difficulty and cost of
the work
Figure 13 Th e parapet of this Grade I listed church had been
repairedcarefully, removing inappropriate cement m ortars and using
lime-basedmortars and renders. The repairs had been specified
carefully to slowdown th e rate of deterioration of the exposed
stone. Once this w ork wascomplete and the m ortars and renders had
set, a new lig htning cond uctorwas installed by a specialist
compan y under a separate contract. Althoughthe com pany had
extensive experience of work i n chu rches and otherlisted
buildings, the li ghtning condu ctor was secured to the
stonework(the most vulnerable part of the parapet wall and the most
difficult torepair) and so increased the risk of accelerated d
eterioration. Thi sdamaging work was not in t he spirit of the
careful repairs previouslycarried out, an d could easily have been
avoided. It would have beenbetter to secure the conductor to the m
ortar, which by its nature isrepairab le and replaceable. Th e
lesson is that, however experienced thecontractor, it is important
to agree with them on site exactly how th einstallation is to be
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Building fabric 1 52 6 6 FixingsMortar and masonry: Provided tha
t the m or ta r i s s t rongenough, it is generally better to
secure fixings in mortarthan into masonry. It provides a degree of
reversibilityand prevents damage to masonry, which is more
difficultand expensive to replace.Timbers an d plaster: Where a
large number of securingpoin ts is required, a separate fixing
plate will provide asuitable surface and reduce t he nu mb er of
fixings to th ehistoric fabric.
Figure 14 A Grade 11*buildi ng was fitted with Christm as
lights, fixedstraight into the br ickwork
Figure 15 Another view of the b uilding in Figure 14 showing the
lightsfixed directly to the lead roof. The lead has been holed and
is at risk ofleaking and the brickw ork has been dam aged: it would
have been betterto fix the cable in the mo rtar
3 ding fabricIn new buildings, insulation a nd draughtproofing
are usedroutinely to reduce heating an d ventilation loads.
Greatcare is required, however, when doing the same thing
intraditional and historic buildings. Th is Section explainswhy,
and what can be done.
3.1 Moisture movement in older buildingsTraditional buildings,
including most historic buildings,tend to be of a solid-wall
construction, buil t prim arilywith porous fabric that absorbs
moisture, but also allows itto evaporate readily. T hi s is often
called th e ability of thebui ld ing fabr ic to 'breath e' .e. it
has a low vapo urresistance. In contrast, modern buildings are
usually madeof harder, strong er an d less pervious materials. T o
excludemoisture, this co nstruction relies on physical barriers
suchas damp-proof courses and membranes, wall cavities
andimpervious cladding.F ig u re s 16 to 18 i l l u s t r a t e t h
e d i f fe r e n c e s. A n o ld e rbuilding uses evaporation and
ventilation to reduce themoisture in the walls to an acceptable
level, i.e. one thatd o e s n o t c a u s e d e c a y, m o u l d g
r o w t h , o r d a m a g e t od e c o r a t i o n s . I n c o n t
r a s t , m a n y m o d e r n i n s u l a t i o ntechniques in c
lude imperv ious vapour con t ro l layers ,des igned to s top mois
tu re f rom indoors d i f fus ing ou tt h r o u g h t h e i n s u l
a t i o n a n d l e a d i n g t o i n t e r s t i t i a
lcondensation. However, if these same impervious layersa r e u se d
in a t r a d i t i o n a l b u i ld in g , t h e y c a n t r a p th
emois tu re a l ready in the wal l and s top i t evapora t ing
,making t he wall damper a nd more prone to decay.
Ventilation throughgaps where tile(or slate) bedsWind b lownrain
and snow
Open firesdrawinglargequantitiesof aira --I enetrationby
drivingrain
\, D a r n p r is in gthrough f loorDamp
risingthroughfoundationsFigure 16 A section of an old building
showing how m oisture movesthrough the structure and the
air(22)
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5/28/2018 Building Services for Historic Buildings
26/98
16 Guide to building services for historic buildings
Household
Figure 17 Moisture control in older buildings. The re is a dynam
icequilibrium between absorption and evaporation.To keep the
fabricreasonably dry and the internal en vironm ent healthy, extra
indoorventilation is required to remove the moisture that
evaporates. Fu rthe rmoisture is driven off when the building is
heated, so any extra heatingmay also require more ventilation
;Isorption ~
Groundmoisture
Heating does notCavity drive off significantamount of
moisture.Dam p only appearswhere bui ldingdefect occursPCt DPM/i
IFigure 8 Moisture control in m odern buildin gs. Cavities
andimpervious layers act as barriers to moisture. D ampness appears
onlywhere there is a defect. Apart from during the initial
drying-out periodto remove construction moisture, additional
ventilation to keep thefabric dry is not norm ally requiredAnother
example of the danger s of inappropr iate , lesspermeable modern
materials is where a hard imperviouscement mortar is used to
re-point soft masonry (brick orstonework). As shown in Figure 19,
the h ard m ortar trapsmois ture and reduces the rate of evaporat
ion f rom theoutside of the wall, so leading to accelerated decay
of themasonry, as in Figu re 20.The fundamental differences in
moisture performance oftraditional and modern buildings make it
imperative that,before making an y de ta i l ed p roposal s , t he
mate r i a l s ,m e t h o d s o f c o n s t r u c t i o n a n d t h
e p a s t a n d p r o p o s e dp e r f or m a n c e a r e a l l id
e n t i f i e d a n d u n d e r s t o o d . A n yprogramme of
repair and alteration needs to take this intoaccoun t and to r
edres s any imbalances in th e in t ende dperformance of the
building. For good results, addres thecauses of the problems, a nd
not just th e symptoms.For example, in Figure 20, the fundamental
problem isn o t t h a t t h e s t o n e i s de c a y in g b u t t h
a t a n u n s u i t a b l ec e m e n t p o i n t i n g w a s u se d
. A l l r e p a i r s n e e d t o u s ematerials an d methods that
are appropriate and consistentwi th the t radi t ional per
formance, e .g . us ing l ime-basedmortars to repoint th is wall.
It would be futile to repair orr e p la c e a n y o f t h e s t o n
e u n t i l a f te r t h e h a r d c e m e n tpoin ting had been
carefully removed. Similarly, if a dam pp a t c h i s f o u n d , d
o n o t c o v e r i t u p , b u t g a i n a nunder s t and ing o f
why i t i s t he re and what needs to bedone to m ake it go
away.
Wall buil t of poro us materia ls Effect of impervious po in t
ingR a $ ptrong cementRay>v
point ing
Deposit ion of b I Deposit ion ofL L II \
-Interstitialcondensation Interstitialcondensation(water
vapour)
b F 1 I ising dampUsual pattern of decay when m ortarused for
pointing i s softer and m oreporous than wal l ing mater ialFigure
9 How hard m ortar can damage masonry(9)
Usual decay pattern whenwall materials are mo reporous than
point ing
3.1 I Differences between tradit ional andmodern materials
Tradi t ional mater ials are of ten relat ively porous , as
inmany stone, brick, earth and tim ber buildings w ith earth-and/or
l ime-based m ortars a nd renders. T hese materials ,used both
externally and internally, enable the fabric oft h e w h o l e b u
i l d i n g t o b r e a th e , w i t h t h e l e v el s o fd a m p
n e s s i n t h e f a b r i c b e i n g c o n t r o l l e d b y a l
l o w i n gmoisture to evaporate readily.Where moisture can
evaporate freely and the traditionalb rea th ing per fo rmance i s
no t impai r ed , the wal l s o fhistoric buildings often remain
relatively dry. Traditionall ime p las t e r s wi th b rea thab le
pa in t fin i shes, su ch aslimewash, play an important part in
this mechanism, bynot only releasing structural moisture but also
absorbingexcess moisture generated internally and dispersing anyp e
n e t r a t i n g a n d c a p i l la r y m o i s t u r e o v e r a
w i d e a r ea .E x t e r n a l ly , t h e p o r o u s m a t e r i
a l s of t r a d i t i o n a l l yconstruct