Guide to Building Services for Historic Buildings - Sustainable Services for Traditional Buildings

85 Pages·2002·4.066 MB·85\85

by  CIBSE

Guide to building
services for historic
buildings
Sustainable services for
traditional buildings
The Chartered Institution of Building Services Engineers
222 Balham High Road, London SW12 9BS
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No part of this publication may be reproduced, stored in a
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means without the prior permission of the Institution.
© November 2002 The Chartered Institution of Building
Services Engineers London
Registered charity number 278104
ISBN1-903287-30-8
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the time of publication. However no responsibility of any
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Typeset by CIBSEPublications Department
Printed in Great Britain by Page Brothers, Norwich.
Preface
If you are about to install, upgrade or renew the services or make alterations to
improve the energy efficiency of an existing building, it is important to ask:
Is the building historic or of a traditional construction?
If it is, you must stopand thinkbefore taking any further action. In most cases, the
building services in a building last typically 15 to 30 years, a fleeting event in the
life of an historic building. For example, some parish churches are over 1000 years
old.
Energy-efficient systems and improved thermal performance will save on running
costs, maintain comfort and reduce carbon dioxide emissions. However, any
alterations or changes to the building services in a traditional building require
careful planning to ensure that the proposed work will be effective and beneficial.
When planning alterations, you need to develop a thorough understanding of the
types of construction, the materials used and the likely impact of any proposed
changes. Modern materials and techniques can often be incompatible with
traditional construction, and careless alterations can cause serious harm to the
building fabric, both directly and indirectly.
Acting without thinking can be damaging, for the building and for the
environment. This Guide will help you to avoid this, so that the existing building
stock can be managed and maintained in a more sustainable manner. It also
illustrates best practice for techniques commonly used in planning, installing and
upgrading building services.
When installed in an appropriate and sympathetic manner, building services can
assist the preventive conservation of historic buildings, prolong their lives in
beneficial use, improve the internal environment, and so bring immense cultural
and environmental benefits. Building conservation is a sustainable form of
property development!
The case studies starting on page 27 illustrate many issues that were taken into
account in making approproate and efficient alterations; and the often imaginative
solutions that results.
Peter Warm and Richard Oxley
September 2002
Contents
Foreword by Simon Thurley vi
Chief Executive, English Heritage
Preface vii
1 Principles 1
1.1 General 1
1.2 Scope and definitions 1
1.3 Aim of this Guide 2
1.4 Target audience 3
1.5 The relationship between building services, energy efficiency and 3
conservation of the existing building stock and the environment
1.6 Legislation 3
1.7 Building Regulations 5
1.8 Design principles 6
1.9 Summary of design principles appropriate for work in 6
older buildings
1.10 Simple nonintrusive ways of improving energy efficiency 7
2 Building services 7
2.1 Modern expectations and standards of service 7
2.2 Increasing sustainability 7
2.3 The value of historic building services 10
2.4 Re-using existing services 11
2.5 Criteria for the selection of new building services in 11
historic buildings
2.6 Installing new building services and upgrading existing ones 11
3 Building fabric 15
3.1 Moisture movement in older buildings 15
3.2 Adding insulation 17
3.3 Ventilation, draughtproofing and fan pressurisation testing 18
3.4 Thermal mass and controls 19
3.5 Conservation heating 19
3.6 Initial and ongoing monitoring 20
4 A design approach for historic buildings 20
4.1 Introduction 20
4.2 The project team 21
4.3 An approach 21
4.4 Design principles 21
4.5 The RIBA Plan of Work 24
4.6 Commissioning 26
4.7 Into the future 26
5 Case studies 27
5.1 Introduction to case studies 27
5.1 Table of case studies indicating relevance of each 27
Glossary 76
References 81
Further reading 82
Useful contacts 83
Index 84
Figure 1What so often happens
This chancel screen in a Grade I listed church was insensitively punched through with heating pipework. The
screen is thought to have Tudor origins and was untouched from the Jacobean period (1603-1689) until this
recent act of vandalism. Simply stoppingand thinkingof more appropriate and less damaging routes before
work started would have reduced greatly the physical damage to irreplacemable hsitoric fabric; and might have
avoided it altogether.
1
Guide to building services for historic buildings
1 Principles efficiency.(2) If we are to achieve worthwhile progress in
achieving sustainable development and reducing carbon
dioxide emissions, we need to increase the energy
1.1 General efficiency of all the UK’s existing buildings, not just the
500000 or so that are listed as of architectural or historic
‘Put at its simplest, sustainability is about ensuring that the interest. This Guide therefore covers not only historic
activities that we have to carry out to meet our range of needs buildings but all buildings of traditional construction.
can be continued indefinitely. To do this, we must ensure that
these activities, whether they are power generation, farming,
waste disposal or tourism, do not irreversibly damage the 1.2 Scope and definitions
environment and its assets’
This Guide is aimed at both historic and traditional
English Heritage, Sustaining the historic environment(1)
buildings.
This Guide illustrates how one can put sustainable
development into everyday practice when upgrading
1.2.1 Historic buildings
building services in the existing building stock. It
promotes a holistic and interdisciplinary approach based
Approved Documents L1 and L2 of the Building
on an appreciation and understanding of:
Regulations(3) treat the following as special cases which
(i) the highly individual nature of many older need to be considered on their individual merits:
buildings, reflecting the unique manner in which
(i) listed buildings;
they have developed over time;
(ii) the materials and methods of construction; (ii) buildings situated in conservation areas;
(iii) the existing and intended performance; and (iii) buildings of local architectural or historical
interest and which are referred to as a material
(iv) the formal recognition and protection offered by
consideration in a local authority's development
legislation.
plan; and
Many older buildings give a special value and interest to (iv) buildings within national parks, areas of
our culture: they are of architectural and/or historical outstanding natural beauty and world heritage
importance and their materials and methods of sites.
construction are no longer in common use. Their perfor-
mance characteristics are different from those of modern Additional legislation formally protects scheduled ancient
buildings. Their formal recognition by legislation, monuments, listed buildings and buildings in con-
Building Regulations and British Standards places an servation areas.
obligation on those who work with older buildings to
reflect and take account of these qualities. Before the start of planning and design of building
services and energy-efficiency measures, all historic and
Older buildings are a nonrenewable resource which needs traditional buildings — not just those with statutory
to be treated as such. This Guide highlights basic prin- protection — need care and attention to understand what
ciples to consider when working with them. Their they are, how they work and the performance required.
individuality prevents it being prescriptive — it identifies This background will then dictate the appropriateness,
issues that should to be taken into account, but each case compatibility and nature of alteration and improvement
must be considered on its own merits. that can be carried out.
The important and sensitive nature of many older
buildings and their fabric demands that work on them: 1.2.2 Traditional buildings
(a) is carried out in an appropriate and compatible
For the purpose of this Guide, traditional buildings
manner;
include not only buildings formally recognised for their
(b) takes proper account of the way they were architectural or historic interest, but all buildings that
constructed and were intended to perform; need to be approached in a manner which reflects the
individual characteristics of their construction.
(c) causes the minimum amount of intervention; and
(d) is reversible wherever possible. Traditionally constructed buildings can be of any size,
shape or form. Construction materials are diverse,
It is recognised as a global priority to continue to use the sometimes even in a single building. Walls are not only of
existing building stock while improving its energy stone and brick, but can be of earth (cob) or historic
2 Guide to building services for historic buildings
timber frames (often with thin render or weatherboard (cid:1) Sometimes, insulation can be added relatively
cladding, or with infill between the structural timbers). easily, as in case study 3, while in other buildings
it may be aesthetically or technically unsuitable, or
Most modern buildings are made of hard, strong and potentially damage or obscure historic features
impervious materials. To exclude moisture, they rely on (there may be occasions when only specific
physical barriers such as damp-proof courses and insulation materials are suitable, see case study 3).
membranes, cavity walls and cladding. Historic and
(cid:1) In one building draughtproofing may be highly
traditional buildings are completely different. Many have
desirable, whereas in another it may cause internal
solid walls and most have porous fabric which both
moisture levels to rise unacceptably and perhaps
absorbs and readily allows the evaporation of moisture.
lead to outbreaks of mould and rot.
This is often known as the ability of the building fabric to
‘breathe’, i.e. to have a low vapour resistance. It is often
inappropriate to repair such buildings with modern 1.3.1 Improving the sustainability of the
materials. For example, if soft sandstone walls are existing building stock
repointed with hard Portland cement rather than soft lime
mortar, not only will they look different and lose their
In August 2002, CIBSE took part in the Johannesburg
attractive patina of age, but the new pointing may well
‘Earth Summit’ at which a ‘Charter for Action’ was signed
cause the sandstone to weather badly, spall and erode —
by participants in the Global Alliance for Building
while the hard cement remains (see Fig. 20 on page 16).
Sustainability. That Charter commits signatories to work
in various ways to support and accelerate sustainability in
Traditional buildings account for one-quarter of the UK’s the built environment.
existing building stock. Making appropriate and efficient
alterations to them as opportunities arise will be a positive Four principal aims when seeking to improve the
and worthwhile contribution to reducing carbon dioxide sustainability of the existing building stock are listed
emissions. below. Their achievement will help to put good
sustainable practice into everyday use, make a significant
Figure 2 shows the proportion of UK buildings to which contribution to the appropriate and sympathetic
the principles in this Guide may apply. Although most preservation and beneficial use of existing buildings and
historic buildings are of traditional construction, some achieve worthwhile reductions in carbon dioxide
listed buildings are relatively new, or include highly emissions.
innovative or unusual construction methods, needing
special consideration. Examples are shown in the case
Aim 1: Preserve historic fabric
studies in Section 5 (e.g. case study 7).
(cid:1) Adopt a respectful approach to the building and its
fabric.
1.3 Aim of this Guide
(cid:1) Understand how air and moisture moves in older
buildings.
This Guide aims to make a sustainable approach to
historic and traditional buildings an everyday activity, not (cid:1) Avoid inappropriate and incompatible materials
the exception. Recognition of the special characteristics of and allow the fabric to ‘breathe’.
these buildings and how best to meet their needs will be a
fundamental step towards the better and more sustainable
Aim 2: Extend the beneficial use of older buildings
management of these existing resources. By adopting good
practice, one can simultaneously achieve social, cultural, (cid:1) Avoid building services that are expensive to run
economic and environmental benefits.
or maintain.
Within an overall aim to improve both the internal (cid:1) Seek to provide modern standards of ac-
environment and energy efficiency, it is important to take commodation.
account of the particular circumstances of the building (cid:1) Adapt existing buildings sympathetically and
and to balance all the issues. For example:
appropriately to modern demands and re-
quirements.
Historic
Aim 3: Reduce carbon dioxide emissions
Traditional – 3%
(cid:1) Install efficient plant.
Traditional – 22% (cid:1) Use cleaner fuels.
(cid:1) Make higher health and comfort standards
Modern – 75% affordable without compromising the building or
the environment.
Historic (cid:1) Reduce fuel bills.
modern <1%
(cid:1) Improve the thermal performance of the building,
but in ways which do not conflict with the historic
features, the intended performance or the health of
Figure 2 Applicability of this manual to UK building stock the occupants and users.
Principles 3
Aim 4: Specify environmentally conscious materials This Guide illustrates the principal factors which need to
be taken into account to achieve more sustainable ways of
(cid:1) Assess the whole life costs of new and existing
improving the building services and energy efficiency of
materials before making changes.
existing buildings, and to obtain an appropriate balance
(cid:1) Assess the impact of new materials on the between historic building conservation and energy con-
environment. servation.
(cid:1) Assess the impact of new materials on the health of
There is a complex relationship between building services,
both those who install them and the users of the
energy efficiency, air and moisture movement and the
buildings.
conservation of the existing building stock. If only one
part of this is considered (e.g. building services, historic
buildings or energy efficiency) the oversimplified view can
1.4 Target audience
lead to potential dangers to the building, the historic
fabric and the environment. Even apparently familiar
This Guide will help all those who specify, install or wish
things should not be taken for granted. For example, at
to improve the services and energy efficiency of buildings
Berg Cottage (case study 2) many people would have
of traditional construction particularly those formally
expected the old single-glazed windows to have been the
identified as of architectural or historic interest, e.g.
main source of high air infiltration, and have wanted to
upgrade or replace them. In fact, most of the excess air
(cid:1) building services engineers
came through the fabric, especially the walls.
(cid:1) principal and specialist contractors
The three pillars of global sustainability, underpinning
(cid:1) manufacturers and suppliers
this Guide, are:
(cid:1) structural engineers
Environmental: conserving our environment; issues such as
(cid:1) architects global warming, pollution, biodiversity;
(cid:1) building surveyors Social: ensuring that human needs are met; issues such as
employment, self government;
(cid:1) quantity surveyors
(cid:1) maintenance and facilities managers Economic: ensuring that resources are available; issues
such as funding, comparing schemes, developing
(cid:1) project managers and cost consultants self-sufficiency.
(cid:1) clients — building owners and users
(cid:1) registered installers of equipment (e.g. FENSA for 1.6 Legislation
windows, OFTEC for oil-fired heating inst-
allations and CORGI for gas installations)
This is a brief introduction to a small part of the existing
(cid:1) building control officers (and external providers of legislation. The complexity of the legislation and the
building control services) individual nature of older buildings make it impossible to
provide detailed guidance here. Each building must be
(cid:1) conservation officers (and nominated officers in assessed individually. If there are any doubts or concerns,
areas which have no dedicated conservation advice must be sought from the local authority
officer) conservation officer and the building control officer: it
(cid:1) historic building inspectorates and their advisers can be helpful to have an early meeting with them
together. Where the building is of special interest (e.g. a
(cid:1) funding bodies and their professional advisers scheduled ancient monument or a building with Grade I
(cid:1) conservators and historic building specialists who or II* listing), the Historic Buildings Inspectorate may
also need to be consulted.
may not themselves realise the extent to which
energy and building conservation objectives can be
harmonised. 1.6.1 Background information
Buildings in the UK have three principal forms of statu-
1.5 The relationship between
tory protection:
building services, energy
(a) scheduled ancient monuments
efficiency and conservation of
(b) listed buildings
the existing building stock and
(c) buildings situated in conservation areas.
the environment
There are many reasons why older buildings require this
‘It is depressing, at a time when highly sophisticated plant is
protection, e.g. type, method of construction, style, special
being used for environmental control, to realise that throughout
structural or aesthetic features or finishes, and associations
much of history, buildings themselves were highly developed
with famous people, historic events or their designers and
examples of applied science, achieving high levels of
builders. Each building has its own particular qualities
performance even when designers could not define or quantify
that contribute to its special interest. The controlling
the factors that they took into account.’
legislation differs from country to country and any
Peter Burberry, Deteriorating design(1978) assessment of a protected building or any advice or
4 Guide to building services for historic buildings
recommendations made will need to reflect the relevant 1.6.4 Conservation areas
controls in force locally.
In conservation areas, there is generally a presumption in
favour of retaining buildings which make a positive
1.6.2 Scheduled ancient monuments
contribution to the character or appearance of the area;
and consent is required to totally or substantially
Ancient monuments are primarily protected under the demolish any building, whatever its quality. Minor
Ancient Monuments and Archaeological Areas Act 1979 developments are controlled to ensure that alterations do
and are not subject to the Building Regulations. They are not detract from the conservation area’s appearance:
mostly structures (e.g. ruins), although a few buildings — controlled alterations may, depending on the individual
or parts or buildings — are scheduled. The number of conservation area, include certain types of cladding,
scheduled monuments is small, so they will not often be inserting dormer windows and putting up satellite dishes
encountered. Note that scheduled monument consent is visible from the street. Conservation area status alone does
required for almost ANY work to a scheduled monument not provide the scope for stringent control, particularly in
— including repair. If work is contemplated, the Historic comparison with scheduled monuments and listed build-
Buildings Inspectorate must be approached for advice ings.
before anything at all is done.
For ‘dwelling houses’ in a conservation area, an ‘Article 4
Direction’ can give increased legal protection. This will
1.6.3 Listed buildings
remove permitted development rights affecting some
aspects of the external appearance, typically doors,
In England and Wales, listed buildings are protected windows, roofs and frontages. There may also be control
primarily under the Planning (Listed Buildings and over adding external services such as gas and drain pipes,
Conservation Areas) Act 1990. The equivalent legislation extract grilles and boiler/terminal flues, especially to parts
in Scotland is the Planning (Listed Buildings and of the building visible from the street and other public
Conservation Areas) (Scotland) Act 1997 and in Ireland is places. Not all conservation areas have Article 4 direct-
the Planning (NI)Order 1991. Listed buildings are graded ions, but where they are in force they influence the extent
to show their relative architectural or historic interest. In and nature of alterations that can be made, even to
England and Wales the grades are: unlisted buildings.
Grade I: buildings of outstanding historic or architectural
interest 1.6.5 Recommended approach for buildings
protected by legislation
Grade II*: particularly important buildings
(i) Determine whether the building is protected or
Grade II: of special interest, warranting every effort to not.
preserve them.
(ii) If it is protected, obtain a copy of the formal
description, e.g. the list description, to determine
In Scotland and Northern Ireland, generally similar
what the special interest is. The list description
grades A, B and C are used.
can usually be obtained from the local authority or
the Historic Buildings Inspectorate.
Works that affect the character of a listed building require
listed building consent. Consent is not normally required (iii) Make early contact with the local authority
for like-for-like repairs. Listed building controls apply to conservation officer to discuss initial proposals
works, both externally and internally, that would affect a and to identify areas where problems may arise.
building's special interest, whether or not the feature
(iv) Identify what other legislation will influence the
concerned is specifically mentioned in the list description.
proposed works, e.g. Health & Safety at Work etc
This effectively means that the whole of the building is
Act.
listed, including existing services, fixtures and finishes.
The listing of a building normally covers its curtilage so (v) For applications where consent is needed, allow
outbuildings may also be listed. Any work that affects the sufficient time for this in the programme,
character of the building can only be carried out once including potential delays (this may add several
listed building consent has been obtained from the local months to the project).
planning authority. It is a criminal offence to carry out
works without such consent. (vi) Obtain all the necessary consents and approvals in
writing before carrying out any work. Only carry
out the work authorised: if changes or additional
Carrying out works without listed building consent can
works are required, notify the local authority
lead to prosecution under the relevant legislation (see
conservation officer (and the Historic Buildings
above). The legislation contains provisions for fines of
Inspectorate, if involved) immediately — another
£20 000 and/or six months imprisonment. However, case
application for consent may be necessary.
law records fines of up to £75 000.(4)
Unauthorised works could constitute a criminal
act (see Section 1.6.3).
Planning Policy Guidance Note 15 (PPG 15)(5) provides
detailed advice and guidance for those making or (vii) Allow for periodic visits from the local authority
considering applications for listed building consent in conservation officer (and if appropriate the
England. Similar guidance exists for the remainder of the Historic Buildings Inspectorate) to inspect the
UK.(6-8) works in progress.