Dissertation a

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Anglia Ruskin University
BSc (Hons) Construction Management
‘How to Improve the Thermal Efficiency of
Listed Residential Buildings’
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May 2014

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Declaration by the Author
This work is composed of my original work, and contains no material previously
published, produced or written by another person or organisation except where due
reference has been made. I have clearly stated the contribution of others to the
production of this work as a whole. I have read, understood, and complied with the
Anglia Ruskin University academic regulations regarding assessment offences,
including but not limited to plagiarism.
I have not used material contained in this work in any other submission for an
academic award or part thereof.
I acknowledge and agree that this work may be retained by Anglia Ruskin University
and made available to others for research and study in either an electronic format or
a paper format or both of these and also may be available for library and inter-library
loan. This is on the understanding that no quotation from this work may be made
without proper acknowledgement.
Candidates signature ………………………..……………………….…………
Candidates Student Number……………………………………………………
Date ……………………………………………..………………………………..

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Acknowledgements
I would like to thank Anglian Ruskin University for allowing me the opportunity to
study Construction Management. My supervisor Sunny Nwaubani who as supported
me throughout this module with advice and guidance. The knowledge and expertise
provided by Dayle and Andy has been very helpful. Their ‘Conservation of Historic
Buildings’ short courses have been i nvaluable i n helping me to complete my
dissertation. Thank you to the participants who took the time to fill in my
questionnaires. I am grateful to my family for encouraging me and helping me remain
focused over the last three years. Finally, I would like to thank my father for inspiring
to investigate the topic of this dissertation.
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Abstract
 This dissertation investigates the reasons why listed building should be
thermally upgraded. It discusses the barriers to improving the thermal
efficiency of listed buildings, and the methods that can be used to improve
their thermal performance.
 The literature review discusses the advice given in various guide books
relevant to the topic. It also discusses current legislation on listed buildings
and energy efficiency. The literature review is supported by a survey of
construction professional that specialise in listed bui ldings. This is conducted
to gain an understanding of the methods they prefer to use when upgrading
the thermal efficiency of listed buildings.
 The findings of the research suggest that there are two major barriers
associated with retrofitting listed buildings in order to make them more
thermally efficient. These are the listed building legislation and the risk of
decay from damp. The results of the survey generally correlate with the
advice given in the literature review.
 The conclusions propose that heritage conservation is about the management
of change in order that the heritage value in a building is preserved. Before
applying for planning permission to make alterations to a listed building, a
detailed investigation should be conducted to show how the alterations could
affect the building in the present and in the future.
Key Words:
 Legislation
 Regulations
 Conservation
 Conduction
 Convection
 Decay
 Insulation
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Contents
1.0 List of Figures and Charts....................................................................................... vii
2.0 Introduction.................................................................................................................. 1
2.1 Limitations ................................................................................................................ 2
2.2 Aims and Objectives............................................................................................... 3
2.3 Structure ................................................................................................................... 3
3.0 Literature Review ....................................................................................................... 5
3.1 Listed Buildings and Conservation Act 1990...................................................... 5
3.2 Building Regulations Part L1B .............................................................................. 8
3.3 Conservation Principles ......................................................................................... 9
3.4 Problems with Historic Bui ldings ........................................................................11
3.5 Insulation Materials...............................................................................................14
3.6 Walls .......................................................................................................................16
3.7 Windows .................................................................................................................18
3.8 Floors ......................................................................................................................23
3.9 Roofs.......................................................................................................................25
4.0 Research Methods ...................................................................................................27
4.1 Literature Review .....................................................................................................27
4.2 Questionnaire............................................................................................................27
5.0 Ethics Statement ......................................................................................................30
5.1 Participants Information Letter............................................................................30
5.2 Participants Consent Form..................................................................................31
5.3 Ethics Tick Sheet ..................................................................................................32
6.0 Results .......................................................................................................................33
7.0 Conclusions and Recommendations ....................................................................44
7.1 Conclusion .............................................................................................................44
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7.2 Recommendations................................................................................................45
8.0 Further Research .....................................................................................................47
9.0 References ................................................................................................................48
10.0 Bibliography ............................................................................................................49
11.0 Appendices .............................................................................................................50
11.1 Appendix A – Questionnaire ............................................................................50
11.5 Appendix B –Participant Information Letter...................................................57
11.6 Appendix C – Participant Consent Form .......................................................58
11.7 Appendix D – Tutorial Sheet ...........................................................................59
11.7 Appendix E – Original Illustrations..................................................................60
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1.0 List of Figures and Charts
Fig 1 – Traditional Stone Wall 12
Fig 2 – Traditional Solid Wall 12
Fig 3 – Moisture Ingress 13
Fig 4 – Insulation Materials 15
Fig 5 – Insulation Stopping at Joist 17
Fig 6 – Insulation Covering Joist 17
Fig 7 – Traditional Glazing Bar 21
Fig 8 – Modern Glazing Bar 21
Fig 9 – Traditional Glazing Bar with Slim Unit 22
Fig 10 – Suspended Timber Floor with Foam Boards 24
Fig 11 – Suspended Timber Floor with Quilts 24
Fig 12 – Cold Roof 25
Fig 13 – Warm Roof 26
Chart 1 – What natural insulation materials would you prefer to use? 33
Chart 2 – What mineral insulation materials would you prefer to use? 34
Chart 3 – What petrochemical insulation materials would you prefer to use? 35
Chart 4 – What composite insulation materials would you prefer to use? 36
Chart 5 – What methods would you most prefer to improve the thermal
efficiency of a cold pitched roof?
efficiency of a warm pitched roof?
efficiency of solid masonry wall?
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37
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efficiency of a wattle & daub/lathe & plaster wall?
efficiency of solid masonry/concrete floor?
efficiency of a suspended timber floor?
efficiency of a window?
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40
41
42
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2.0 Introduction
The title of this project is “How to Improve the Thermal Efficiency of Listed
Residential Buildings”.
It is now widely accepted that human activity is the major cause of global warming.
Increasing emissions of greenhouse gases such as methane and carbon dioxide are
making global temperatures rise. As a result sea levels are expected to rise and
weather to become more extreme. (PRT, 2010, p.1) A landmark report by the IPCC
(International Panel of Climate Change) says scientists are 95% certain that humans
are the "dominant cause" of global warming since the 1950s. (BBC, 2013) Fuel
poverty is another major problem in the UK, often with the most vulnerable people
bearing the brunt. Energy is increasing by an average of 16% year on year between
2004 and 2008. (PRT, 2010, p.1)
The UK contributes 1.73% of the total global carbon emissions, making it the 9th
largest contributor in the world. (European Commission, 2012) 44 -48% of the UK’s
carbon emissions is accounted for by the built environment. Approximately 27% of
these emissions are produced by domestic buildings and about 22% by public and
commercial buildings. 20% of these domestic buildings were constructed before
1919. Another 20% were constructed between 1920 and 1939. Space and water
heating is responsible for around 75% of carbon emissions produced by dwellings
with the rest coming mostly from lighting and appliances. (English Heritage, 2012)
Climate change is inevitable, but if we want to minimise its future impact we must
make our buildings more energy efficient and more capable of withstanding our
increasingly erratic weather patterns. (PRT, 2010, p.1)
The UK is committed to an 80% reduction of carbon emissions by 2050. Much
attention has been focused on designing new builds to be more energy efficient,
however because 70% of the UK’s building stock by 2050 will be buildings that exist
now, surely more investment should be spent on improving the energy efficiency of
our existing buildings. However, adapting buildings once they are already built is
inherently more difficult as there would not be an allowance for alterations in the
design of a building. (PRT, 2010, p.1) Still, this is a problem that must be addressed,
as the only other alternative is to demolish the building and start again which is
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counterproductive, creates a lot of waste and uses up precious energy that could be
saved. It also wastes the embodied energy that went in to constructing the original
building. (English Heritage, 2012, p.7)
This is particularly so for the UK’s stock of listed buildi ngs and those in conservation
areas. It is particularly complicated to improve the energy efficiency of buildings with
historic or architectural interest, as statutory requirements restrict what alterations
may be made. This raises the question of which methods can be used to improve
their energy efficiency within legislative boundaries?
Many listed buildings actually have energy efficient features and design because
they were built at a time when energy was relatively more expensive. (English
Heritage, 2012, p.7) Traditional buildings very often had a high thermal mass, which
meant they were good at naturally regulating the internal temperature, so it would be
warmer at night during winter and cooler in the day during summer. (The PRT,
2010, p.11)
However in this day and age we see it as a necessity to heat our homes during the
winter for personal comfort. The trouble is that old buildings will quickly absorb this
heat into the fabric of the building, rather than letting it heat the occupants. (M.G.
Cook, 2009, p.33) Consequently, to keep the heat inside the building some may
resort to modern methods, such as installing insulation on the inside or the outside of
external walls. The trouble with this method is the insulation acts as a barrier to
moisture and as traditional building materials are very porous so anything stopping
the moisture escaping will trap it in the building fabric, resulting in mould and decay.
(SPAB, 2013, 2013, p.37-38) Therefore, we need new methods of improving the
energy efficiency of listed buildings. Otherwise people will not be inclined to live in
them and keep them maintained, without occupancy they will fall in to a state of
disrepair and we will lose our heritage. (M.G. Cook, 2009, p.16)
2.1 Limitations
The scope of the study will have to be limited due to many contributing factors such
as time, resources and word count. Therefore the research will only cover listed
buildings in the UK, meaning that listed building regulations for other countries will
not be taken in to account. Neither will considerations particular to warmer or colder
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environments than the UK be considered. The research wi ll not cover historic
buildings which are not listed as these do not have barriers such as statutory
protection. Only residential buildings will be covered as commercial and industrial
building etc will have separate requirements. As the majority of carbon emissions
from listed bui ldings are a result of heating, the dissertation will only cover thermal
efficiency. Also, this will only mean for the actual fabric of the build, not services such
as space and water heating. Neither will it cover energy efficiency such as renewable
energy sources or more efficient energy systems.
2.2 Aims and Objectives
Aim:
This dissertation will investigate barriers to improving the thermal efficiency of listed
buildings and buildings in conservation areas. It will discuss the recommended
methods of improving thermal efficiency and investigate what methods professionals
in the industry prefer to use. At the end of the dissertation advice wi ll be given on the
process of upgrading the thermal performance of listed buildings.
Objectives:
 Investigate the current statutory regulations for listed bui ldings and energy
performance standards for existing dwellings.
 Review current literature on methods of retrofitting listed/historic building for
energy efficiency.
 Survey companies and professionals who specialise in listed buildings to yield
quantitative data.
 Analyse the data in conjunction with information from the literature to come to
a conclusion and recommendations.
2.3 Structure
The study will be structured in the standard way, using the following chapter layout:
• Literature Review
• Methodology
• Ethical Guidelines
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• Results and Analysis
• Conclusion
• Recommendations
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3.0 Literature Review
There are a number of organisations who have published material on retrofitting
listed buildings for energy efficiency and sustainability. Two major organisations are
English Heritage and the Society for the Protection of Ancient Buildings (SPAB).
They provide advice on all matters to do with heritage conservation.
English Heritage is an executive non-departmental public body of the British
Government sponsored by the Department for Culture, Media and Sport (DCMS). It
advises on the conservation of the historic environment in England and has the
responsibility of registering and enforcing the protection of listed buildings and
ancient monuments. (English Heritage, 2014)
The Society for the Protection of Ancient Buildings is a registered charity that is
involved in all aspects of the survival of buildings which are old and interesting. They
offer conservation advice and training and produce technical publications, providing
practical guidance on the repair and care of old buildings. (SPAB, 2009)
Energy efficiency is becoming a key issue for those who work with historic buildings.
Research has been carried out on the performance of various traditional buildings
materials. Historic Scotland has produced reports on the performance of sandstone
construction, while English Heritage is currently looking at brick construction. SPAB
have taken the responsibility for researching most other walling types, including
wattle & daub panelling, cob, limestone, slate, granite etc. (SPAB, 2009)
There are also many official statutory documents relating to conservation principles
and bui lding regulations. The literature is concerned with the Listed Buildings and
Conservation Act 1990 and it also discusses the relevance of the Buildings
Regulations Approved Document L1B - Conservation of fuel and power.
3.1 Listed Buildings and Conservation Act 1990
Section 1 of the Planning (Listed Building and Conservation Areas) Act 1990
imposes the duty on the Secretary of State to approve a list of buildings with
“special” architectural of historic interest i n order that the planning authorities can
protect them. This enforcement comes in the form of listed building consent,
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conservation area control and scheduled monument consent. (HM Government,
2014, p.2)
Listed bui lding consent is required when a development could affect the character of
or special architectural or historic interest of a listed building.
There are certain grades that a listed building can be given, these are the following:
• Grade I - Buildings that are of exceptional interest
• Grade II* - Buildings that are particularly important and of more than special
interest
• Grade II- Buildings that are of special interest (English Heritage, 2012, p.22)
Architectural Interest:
A building may be regarded as having special architectural interest based on its own
merit for having exceptional visual quality in its design, decoration or craftsmanship.
A building may also have special interest because it is an exceptional example of a
particular building type or technique, such as a building that demonstrates
technological innovation. (English Heritage, 2012, p.24)
Historic Interest:
A building can be regarded as having special historic interest if it illustrates important
aspects of the nation’s economic, cultural, or military history. It may be particularly
characteristic of the local region, or it may symbolise a particular era of industry. The
building may even have ties with nationally recognised people.
It is the policy of the Secretary of State that only those buildings that are most
representative or most significant examples of their type that should be listed. When
a number of buildings of similar type or quality survive it is necessary to compare
them in order to choose which ones to list. (English Heritage, 2012, p.24)
Age and Rarity:
One of the major considerations for listed buildings is how rare it may be. The older a
building is the less surviving examples there are likely to be and therefore the more
likely the building is to be listed.
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The generic principles used are listed below:
• Before 1700 - All buildings where most of the original fabric is intact are listed.
• 1700 to 1840 - Most buildings are listed.
• After 1840 - A greater proportion of these bui ldings have survived as more
were built, therefore stricter selection is needed.
• After 1945 – Very careful selection is required for buildings after this period,
they are usually only listed if of outstanding quality and under threat. (English
Heritage, 2012, p.25)
Group Value:
Another consideration the Secretary of State will take in to account is the value of
groups of buildings that demonstrate communal history and character. Where there
is a historical functional relationship between buildings it can shed light on how
society functioned in the past. (English Heritage, 2012)
When conservation officers decide whether to grant planning consent on a listed
building they take in to account the desirability of preserving the building, its setting
and/or features that make it of special architectural or historic interest. In this
instance conservation does not mean preservation, in the sense the building cannot
be altered in any way. Instead it means the careful management of change, so as
not to compromise the integrity of the interest. The significance of a building can be
harmed or lost through alteration or destruction. Heritage assets are irreplaceable;
therefore any damage or loss will need clear and convincing justification. (English
Heritage, 2012)
If a development will cause substantial harm to or total loss of significance to a listed
property, local planning authorities should refuse consent. The exception to this rule
is when there is substantial public interest that outweighs the damage or loss. The
following exceptions also apply:
 The particular nature of the heritage asset inhibits all reasonable use of the
property
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 No viable use of the heritage asset can be arranged through appropriate
marketing that will facilitate its conservation; and
 It is shown to be impossible for conservation to be funded by grants or some
form of charitable or public ownership; and
 The damage or loss is outweighed by the benefit of putting the property back
into use. (English Heritage, 2012, p.25)
When a development proposal will lead to less than substantial harm to the
significance of a listed property, the harm should be weighed against the public
interest, including safeguarding its most viable use. A balanced judgement is
required regarding the scale of harm or loss against the significance of the heritage
asset. It is up to the relevant planning body to decide whether the consequences of
development are justifiable given the significance of the building. (English Heritage,
2012, p.26)
3.2 Building Regulations Part L1B
The Building Regulations govern the standard for alterations to thermal elements of
existing buildings. The guidelines are set out in the Approved Document L1B -
Conservation of fuel and power.
The building regulations come in to effect for a variety of circumstances, the ones
that concern alterations are:
• “When certai n changes or renovations are made to thermal elements”,
thermal elements are external walls, floors or roofs”.
• “When changes are made to controlled fi ttings or services”, controlled fitti ngs
are windows, external doors, roof lights and roof windows. Controlled
services are space heating and hot water systems, mechanical ventilation
and cooling, and fixed artificial lighting”. (HM Government, 2014, p.7)
Section 3.6 of the Approved Document L1B - Conservation of fuel and power
(existi ng dwellings) states “There are exemptions from the energy efficiency
requirements that may apply to building work to existing dwellings”:
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Buildings which are:
• “Listed in accordance with section 1 of the Planning (Listed Buildings and
Conservation Areas) Act 1990”;
• “In a conservation area designated in accordance with section 69 of that Act”; or
• “Included in the schedule of monuments maintained under section 1 of the Ancient
Monuments and Archaeological Areas Act 1979.”
For these buildings, the exemption applies only to the point that compliance with the
energy efficiency requirements would excessively alter the character or appearance.
(HM Government, 2014, p.8)
The Building Regulations state:
The application of the energy efficiency requirements in accordance with the
provisions of the approved document L1B and up to, but not beyond, the point at
which:
i) “Unacceptable alteration to the character and appearance of historic buildings will
be likely to occur.”
ii) “The ability of traditional buildi ngs to ‘breathe’ to control moisture and potential
long-term decay problems is likely to be unacceptably impaired.”
When considering work on a building that falls into one of the planning exemptions
listed in section 3.6, the objective should be to increase energy efficiency as far as
possible without damaging the character or appearance of the building. Materials
should not be used that would be detrimental to the resilience of the building. (HM
Government, 2014, p.8)
3.3 Conservation Principles
English Heritage’s conservation principles identify certain considerations that should
be addressed when proposing alterations to listed buildings. The four major
principles that English Heritage promote are minimum intervention, compatibility,
reversibility and authenticity.
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When alterations to improve energy efficiency are proposed, regard should be given
to:
• Understanding the building to avoid any alterations that could damage the property.
• Minimising disturbance to existing fabric.
• Making it possible to reverse any changes without damaging the existing fabric in
the process. (English Heritage, 2012, p.22)
The following tests need to be satisfied when considering alterations:
• There is sufficient information on the building to fully comprehend the possible
impacts of alteration on the significance of the building.
• The proposal will not materially damage the significant features of the building.
• The proposal will be of sufficient quality and workmanship that wi ll be valued both
in the present and in the future.
• The long-term consequences of the proposal can be demonstrated to be benign
and the design should allow for any solutions in the future. (English Heritage, 2012,
p.25)
Minimum intervention:
All works on a building should be kept to as little as possible to retain the maximum
amount of historic fabric and the significance it holds.
Compatibility:
All changes should be made using materials and techniques that are compatible with
the traditional fabric. Modern materials can be quite rigid, therefore to ensure it
weathers like the original material it should be slightly weaker. Also modern materials
tend to be less permeable and when used alongside original fabric it can accelerate
decay, so a solution should be found to guarantee this will not occur.
Reversibility:
Where changes are detrimental to the significance of a building they should be
reversible. This means that if the significant features are temporarily obscured, in the
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future the historic fabric can be returned to its original state without being damaged.
This principle can be applied from individual repairs to major extensions.
Authenticity:
All development to a building should appear authentic and respect the history of the
fabric.
This implies that:
• All new work should appear as if it was built at the same time as the old.
• All the phases that a building has gone though in its past history should be clearly
visible.
• Restoration should be avoided where it is based on speculation, apart from
instances where documentary and/or physical evidence of previous form is available.
• Nothing of important significance should be removed. (English Heritage, 2012,
p.27)
3.4 Problems with Historic Buildings
Most buildings until the early twentieth century had solid walls; in fact around 1 in 5
homes in the UK have solid walls. (SPAB, 2013, p.11) Traditional solid walls were
constructed from bricks, stone or even cob (earth and straw). Where mortar was
used it was generally made from lime and sand. This type of mortar was a lot more
porous than modern mortars. When the building was rendered a lime mix was
normally used and it may have then been lime washed. (SPAB, 2013, p.13) These
traditional materials are very good at ‘moisture buffering’ which means that when it
rains; moisture is easily absorbed in to the wall and when the rain stops it will
evaporate. Inside, walls were plastered with lime or even clay. The moisture created
inside from human activity was absorbed in to the wall and gradually released. Open
flues, chimneys and draughts also helped to disperse internal humidity. This way
moisture within the structure remained in equilibrium and kept the interior dry. (PRT,
2010, p.20)
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Fig 1 – Traditional Stone Wall Fig 2 – Traditional Solid Wall
This diagram shows how the traditional
breathable materials used in solid wall
construction easily absorbed and released
moisture and evaporated rising damp. (SPAB,
2013, p.12)
The traditional construction materials such as stone and brick used in solid walls also
produced a high thermal mass. This means it is good at storing heat and slowly
releasing it during cooler temperatures. This helps moderate temperature
fluctuations and keeps the interior at a steady temperature. (SPAB, 2013, p.10)
Unfortunately in the UK the temperature inside old buildings is quite uncomfortable
compared to modern living standards. It also takes a long time for dense masonry
walls to heat up in the first instance, which therefore means a lot more energy is
used. (PRT, 2010, p.20)
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This diagram shows a typical suspended
timber floor which became common place
from the mid-nineteenth century. By this time
many buildings were constructed from brick.
(SPAB, 2013, p.12)

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In modern buildings the solution would be to install insulation to reduce heat loss in
the building. Insulation materials have low thermal conductivity so when installed in a
building it slows down the rate of heat transfer through the external walls. However,
most modern insulation materials are made from impermeable materials. This
interferes with the bui ldings natural ability to breathe. It holds water in the building
fabric, making them damp, unhealthy and less thermally efficient. Damp walls are
less thermally efficient because water is a better thermal conductor meaning heat
can pass through much easier. SPAP research suggests that 40 per cent more heat
is lost through damp walls than dry ones. Where timbers are embedded in to the
external walls it can cause rot and eventually structural failure of an entire floor.
(SPAB, 2013, p.11)
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This diagram shows how traditional
solid walls are not compatible with
impermeable modern materials as
moisture becomes trapped in the wall.
(SPAB, 2013, p.13)
Fig 3 – Moisture Ingress

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3.5 Insulation Materials
All alterations to upgrade the thermal efficiency of historic buildings should be
compatible with the existing structure, particularly with the need for permeable fabric
that ‘breathes’. Natural i nsulation materials are generally the best for allowi ng the
building to breathe and are also very good at absorbing and releasing moisture
which buffers the changes in humidity. (English Heritage, 2012, p.35) Typical
examples include wool, hemp, flax and recycled newspaper (cellulose). Some
mineral insulation products are also breathable but they are not good at absorbing
water as they slump and the air pockets fill with water. (SPAB, 2013, p.53)
Generally more than one type of insulation is used within one building as the most
appropriate solution should be sought for each section of the building. (English
Heritage, 2012) Insulation comes in qui lts, batts, boards or as loose fill. Quilts come
in long lengths, batts and boards are rigid and come in shorter lengths. They are
usually cut to lengths using a knife or saw respectively. Loose fill is pumped in by
professional installers. (SPAB, 2013, p.49)
The chart overleaf compares the main types of insulation products. It indicates the
form they take, common uses, thermal performance, embodied energy and cost.
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Fig 4 – (SPAB, 2013, p.52)
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3.6 Walls
Generally internal or external insulation of the external solid walls on a listed building
is unacceptable. However, in some cases where the building has external rendering
or cladding that is in such bad condition that it needs to be replaced, external
insulation can be installed underneath without affecting the character of the building.
Internal insulation can also be installed if the plasterwork needs to be replaced.
(English Heritage, 2012, p.52)
External insulation is the better option out of the two, as it keeps the wall warm by
keeping the heat inside. This can potentially eliminate the risk of interstitial
condensation as water vapour will not condense on warm surfaces. Internal
insulation causes the opposite by preventing the heat inside the building from
warming up the masonry. As a result, the temperature of the wall can drop to ‘dew
point’, which is the point where water vapour will condense. Moisture will build up
inside the wall and this is known as interstitial condensation. (SPAB, 2013, p.47)
Another great risk with internal insulation is the point where the insulation stops is
around the floor joists. Traditionally floor joists were embedded in to the wall, thus
creating a thermal bridge. The insulation would encourage condensation at these
points, which could lead to the joists rotting and the whole floor could collapse. In an
effort to stop this, some retrofits may involve lifting floorboards and continuing the
insulation down between the joists. (SPAB, 2013, p.110)
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Fig 5 – Insulation Stopping at Joist Fig 6 – Insulation Covering Joist
This diagram shows internal insulation
stopping at the floor and ceiling, creating a
thermal bridge where the joist is set in to
the masonry. This attracts moisture that can
rot the timber. (SPAB, 2013, p.110)
To reduce the amount of moisture entering the wall most internal insulation systems
incorporate a vapour control layer which is designed to stop water vapour passing
through to the wall. Unfortunately they rarely provide a vapour tight layer and are
very susceptible to breaches. In fact they even contribute to interstitial condensation.
When wind driven rain soaks in to the core of the wall it cannot evaporate in to the
room because the vapour control layer stops it. (PRT, 2010, p.25)
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This diagram shows internal insulation that
has been continued around the joist to
minimise the thermal bridge. (SPAB, 2013,
p.110)

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Timber Framed Walls:
Insulation to timber framed wattle and daub walls is unlikely to receive planning
approval, particularly when the timber frame is visible. However when the wattle and
daub infill panels are in such bad condition that they need replacing , it may be
possible to replace them with ‘hemp-crete’ panels which are made from a mi xture of
hemp and lime. (English Heritage, 2012) This lightweight concrete has good
breathing characteristics which will help reduce heat loss by reducing conductivity.
Casting it in-situ will also make it a lot more air tight around the timber frame. Where
panels can’t be replaced any large gaps between the frames can be filled with
insulation quilt. (SPAB, 2013, p.118 - 119)
3.7 Windows
Windows are one of the most important parts of the building to consider when
improving overall thermal performance. This is because glass is not a particularly
good insulator, especially single glazed panels with no air gap. One of the first
checks to carry out is to see if the window panes have a good seal and the frame fits
tight in the reveal. Timber framed windows can easily go out of shape over time,
causing gaps to materialise around seams. If this is the case, a professional joiner
can make fairly in-expensive repairs to rectify the problem. They will also repair any
other defects such as splits in the timber. If the windows have original shutters the
opportunity should be taken to repair them as well. (PRT, 2010, p.30)
The simplest and least invasive method to improve the thermal performance of old
windows is to install curtains, blinds or shutters. In the majority of cases they will
already be fitted anyway. Taking embodied energy in to account they can be just as
energy efficient as double or secondary glazing. They are also very efficient at
keeping a building cool during the summer months by preventing heat from entering
the building. (PRT, 2010, p.30)
Curtains:
Heavy curtains interlined with fleece are very efficient at reducing heat loss through a
window. They should be hemmed in-situ so they are in contact with the floor and the
ceiling to stop draughts either end. They should also be hung close to the wall to
reduce the gap in between. If a radiator is situated underneath a window, the warm
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flow of air can escape behind the curtain. By placing a shelf above the radiator, this
can be stopped. Sometimes introducing a pelmet to the top of the curtain can also
close of draughts. (SPAB, 2013, p.80-81)
Thermal Blinds:
Thermal blinds incorporate insulating material and reflective layers which minimise
thermal conductivity. A metal runner is screwed to the window frame and magnets
around the edge of the blind hold it to the frame, thus creating an effective seal.
(SPAB, 2013, p.81)
Shutters:
Being made out of wood, shutters work well as insulators. Ideally, a rubber seal or
brush strip should close off the point where they meet. Because traditional shutters
are only used during the night, they cannot help with energy-efficiency during the
day. If the originals are missing but the window is still designed to have shutters, an
ideal solution is to use glazed shutters, which can be closed during the day. The
incorporation of double glazed units within the shutters can further enhance the
thermal performance of a single glazed window. (SPAB, 2013, p.81)
Secondary Glazing:
Secondary glazing is an extra sheet of glass/plastic which is placed behi nd the
existing window. (PRT, 2010, p.31) They can come in glass and plastic forms, some
panels are fixed and others can open. The fixed versions are held on by a self-adhesive
magnetic strip, whilst others have two panes that slide past each other on a
track. Vents are usually installed in the frame to aid ventilation in the air gap,
otherwise condensation can build up.
Secondary glazing can dramatically improve airtightness and reduce heat loss
through conductivity, especially when low-e glass is specified. (SPAB, 2013, p.81)
There should be an air gap of at least 200mm between the two panes to make a
sufficient reduction in heat loss. Although, this would make it impracticable to install
secondary glazing around window seats or windows with shutters as it may impair
their use (PRT, 2010, p.31)
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Surprisingly, plastic sheets are much more discreet than glass as in comparison they
are so lightweight they do not need a trim. (SPAB, 2013, p.87) In the case of glass
panels, to conceal the secondary glazing, the trim should not protrude beyond the
width of the window frame. (PRT, 2010, p.31) In which case, fixed panel glazing is
the more likely choice as the types that open have thicker trims because of the track.
They also have a bar across the middle of the window to divide the panels. To be
hidden it would have to sit behind the mullions on the window. (SPAB, 2013, p.85-
86)
However a fixed panel would not suit windows which are regularly opened to aid
ventilation as they cannot be opened. Fixed panels are much easier to clean and
maintain and they can be removed during the summer to take advantage of solar
gain. However, SPAB comments that depending on the size of the windows and how
many there are; this can be a very labour intensive task. It may require more than
one person to lift out the panels. (SPAB, 2013, p.85) It may also contravene fire
safety regulations. This is one instance where plastic sheets are a good alternative
because they are so lightweight. (SPAB, 2013, p.87)
Double Glazing:
Double glazing is a combination of two sheets of glass with a gap in between to
make a single unit. The space around the edge is sealed and the air gap is generally
filled with argon gas. (PRT, 2010, p.31) This arrangement leads to unit thicknesses
between 24 – 28mm. Most traditional windows have shallow rebates as they were
only designed to accommodate a single sheet of glass which was held in place with
putty. Therefore it would seem impossible to fit double glazing in to the rebate of old
windows. (SPAB, 2013, p.88)
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Traditional glazing bars vary in size but
this example is 15mm deep with
handmade glass 3mm thick. The glass is
held in with putty. (SPAB, 2013, p.88)
Modern glazing bars are
usually 24mm to 28 mm
thick with deep rebates to
allow for thicker units.
(SPAB, 2013, p.88)
Fig 7 – Traditional Glazing Bar
Fig 8 – Modern Glazing Bar

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Yet there is a new generation of double glazing units which are much slimmer and
can be used in some traditional glazing bars. Although, they are limited to the rebate
depth of individual windows. These varieties are filled with low conductivity gases
such as krypton or xenon making them just as efficient at only 10 - 12mm thick. They
can even come with an outer layer of handmade glass to suit the style and age of the
house. Other options include vacuum-filled units but these come with spacers
between the panes which are clearly visible. It is important to bear in mind that twice
the amount of glazing will be added to the window, so the ext ra weight can strain the
hinges and unbalance sashes. (SPAB, 2013, p.89)
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Slim-profile units as evidenced here will
fit within the rebate of some traditional
glazing bars. As before, the glass can be
held in place with putty. (SPAB, 2013,
p.88)
Fig 9 – Traditional Glazing Bar with Slim Unit

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3.8 Floors
Ground floors in old houses were traditionally either solid or suspended in
construction. Solid floors were made from stone flags, bricks or ti les laid directly on
to compacted earth. Suspended floors are formed of timber board nailed to joists
with ventilation underneath. (PRT, 2010, p.25)
The point of ventilating under floorboards was to allow air to circulate and reduce the
build-up of moist air which could rot the timbers. Unfortunately this created draughts
in the gaps between the floorboards, a problem which is now solved with tongue and
groove floorboards. (English Heritage, 2012, p.54) In the case of traditional
floorboards the gaps can be draught proofed with all manner of materials including
draught strips, string, expanding foam, silicone, papier-mâché and even thin strips of
wood. (SPAB, 2013, p.130) With draught proofing installed heat loss will be reduced
through convection. Unfortunately this sti ll won’t stop the considerable heat loss that
occurs through suspended floors, so sometimes insulation is required. (English
Heritage, 2012, p.54)
When there is only a shallow void beneath the floor boards it becomes necessary to
lift them up to install the insulation. In most cases permission would not be granted to
lift up historic floorboards because of the risk of damage. However if it is allowed,
then it must be done with great care, especially with tongue and groove as the
tongue can easily spit off. Skirting may also need to be removed. (English Heritage,
2012) Floorboards that were not cut using a sawmill had varying thicknesses and all
had a specific place in order to create a flush surface. Therefore it is very difficult to
relay these types of floorboards as each one has to be numbered. (SPAB, 2013,
p.131)
Insulation is usually installed between the floor joists and either rigid insulation or
quilts are generally used. Common types of rigid insulation that are used include foil
faced foam board or wood fibre boards for their superior k-values and hygroscopic
properties respectively. To hold in rigid insulation, battens are screwed to the base of
the joists for the insulation to rest on. Insulation quilts on the other hand are held up
with netting running underneath the joists. (SPAB, 2013, p.132)
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Fig 10 – Suspended Timber Floor with Foam Boards
This diagram shows foam boards being suspended by battens in between the joists of a
suspended ground floor. The air bricks allow ventilation in to the underside of the floor.
(SPAB, 2013, p.132)
This diagram shows insulation quilt being supported underneath the floor using garden
netting. (SPAB, 2013, p.132)
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Fig 11 - Suspended Timber Floor with Quilts

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3.9 Roofs
Cold Roofs:
For cold roofs, insulation is generally laid horizontally across the top of the ceiling, in
between and maybe on top of the joists. There are two main types that are used for
this, either quilts or loose fill insulation. Loose-fill insulation is pumped in with a long
hose to fill the roof space to the desired thickness. This is not recommended where
the roof space is draughty as the cellulose fibres can easily be blown around, making
the insulation bed vary in thickness. (SPAB, 2013, p.49)
It is common to have poorly detailed roof eaves in old buildings and sometimes
insulation can block ventilation at the eaves. But this does not mean insulation
should stop before the eaves or thermal bridging will occur at the end of the joists.
The insulation should run up to the wall plate without blocking eaves ventilation.
(SPAB, 2013, p.64)
Fig 12 – Cold Roof
This diagram represents a cold roof. The roof space remains uninhabited and the rafters are
exposed. There is ventilation at the eaves and insulation is laid above the ceiling. (SPAB,
2013, p.60)
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Warm Roofs:
For warm roofs, the insulation is generally fitted along the rafters. There are various
versions of this, these being under the rafters, in between or on top. Either quilts or
batts can be used and the same fixing principles of netting and battens are used.
Insulation above the rafters is referred to as ‘sarki ng’. This is generally the best
solution as it minimises the condensation risk by keeping the roof warm. It is also
creates the least disturbance as most of the work can be carried out on the roof. This
is important if the roof space has historic plaster on the underside. The trouble with
this method is the extra thickness of the insulation would raise the level of the roof,
posing problems for the eaves and verge. A temporary roof covering is also needed.
When installing insulation in between the rafters a ventilated cavity of 50mm must be
left above the insulation. This means if the rafters are less than 80mm then there
won’t be enough space. If the planning officers allow it, it is possible to attach
battens to the underside of the rafters to increase the depth. (SPAB, 2013, pp.67-69)
Fig 13 – Warm Roof
This diagram represents a warm roof. The roof space has become a warm occupied room.
Insulation is installed along the rafter line and covered up by plasterboard. (SPAB, 2013,
p.61)
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4.0 Research Methods
The methodology chapter will discuss the way in which data will be collected for the
dissertation and the reasons why those techniques were chosen. It will explain how
the chosen methods of research will answer the main question of the dissertation.
4.1 Literature Review
The literature review has to be one of the ways that data is gathered. The purpose of
the literature review is to inform the reader of the problems and barriers involved with
upgrading the thermal efficiency of listed residential buildings. Literature such as
books, journals, articles and websites are freely available. All that is necessary is to
find appropriate material from reputable sources, which could be analysed in order to
investigate the research questions. A selection of literature will be used so
information can be drawn from different perspectives. In order to obtain reputable
information, most of the literature will come from guide books from official
organisations, which there are plenty of regarding alterations to listed buildings.
Following the literature review will be the results of the questionnaire, which will be
based on the methods stated in the literature review.
4.2 Questionnaire
In order to investigate what methods construction professionals prefer to use for
improving the thermal efficiency of listed buildings, the decision was made to create
a questionnaire. It would be emailed to various professionals in the construction
industry who deal with listed buildings. Along with the questionnaire will be an
explanation of why they are being invited to participate and what the data would be
used for. Emailing the questionnaire rather than personally delivering it to the
participants will lessen the ethical risks. It also means they can quickly email the
completed questionnaire back rather than having to wait for it to be posted.
The kind of construction professionals that the questionnaire will be sent to include
construction managers, construction consultants and conservation officers. The aim
is to focus on people who are involved in retrofitting projects on listed buildings from
the beginning to the end. These professionals would have the most practical
experience with listed buildings and would therefore have the most reliable opinions.
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Before sending out the questionnaire a pilot study should be undertaken. The pilot
study will involve asking people to fill in the questionnaire as best they can and
asking them if the questions were understandable and if they could answer them
easily. The final questionnaire will be formed around the feedback gained through
the pilot study.
The questionnaire asks the participants to answer 11 closed questions by writing a
number in each box corresponding to their preferred materials/methods for improving
the thermal efficiency of a listed residential building. The highest number would be
their most preferred option and the lowest number would be their least preferred
option. The results wi ll be visually represented on bar charts so the best scoring
methods/materials can be clearly seen.
The participants are told that they can leave the boxes blank if they would never use
that particular material/method or have not heard of it. This also included the boxes
labelled ‘Other’, so if this was left blank it would mean they could not thi nk of any
other material/methods to use on that part of the building or that they wouldn’t use
anything else other than what was stated in the questionnaire.
If they cannot pick a preference between any materials/methods, maybe because
they are just as good as each other, then they are allowed to put the same number in
each box. The participants will also be given the opportunity to write any comments
they may have in a box provided at the bottom of each question.
The first four questions are focussed on insulation materials. They are split up in to
different types of insulation, these being natural, mineral, petrochemical and
composite insulation. These types of insulation were based on the chart titled fig 4
which will also be used to aid the analysis of the results. The participants will be
asked to rank each type of insulation in order of preference. This has been made
easier by splitting insulation into types, as there is less too consider, rather than all
being listed in one question.
The rest of the questions are focused on particular methods. They are split up in to
different sections of the buildings, like it is in the literature review. The participants
will be asked what methods they would use to improve thermal efficiency in each
section of the building; this also takes in to account different types of structure. The
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SID: 1108442
questions are aimed at cold pitched roofs, warm pitched roofs, solid masonry walls,
wattle and daub/lathe and plaster walls, solid masonry/concrete floors, suspended
timber floors and windows. The questionnaire is designed to cover all possible
structures, to understand what methods professionals prefer using in different
circumstances.
By finding out the opinions of professionals the results can be compared with the
information in the literature review and a balanced conclusion can be made to the
principle question of the dissertation, how to improve the thermal performance of a
listed residential building?
To receive an accurate result on the questionnaire it is important to put the
insulation/methods into different lists. This allows the participants to personally
consider the disadvantages and advantages of each option. Being asked to make
their own choices wi ll provide a more diverse result. Replying with the most
commonly used products would probably produce a similar outcome. The
information will be collected on a bar chart as it is easy to distinguish which options
score higher than others. The larger the bar shows the more favoured choice. This is
why the questionnaire asks the participants to show thei r preferred decision with
the highest number and the least favoured with the lowest number.
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5.0 Ethics Statement
The questionnaire and the subsequent data raise ethical issues. So to eliminate
these issues, certain ethical considerations were observed and dealt with before
inviting the participants to take part in the investigation.
The participants who were invited to take part in the questionnaire were a mixture of
employees in the construction industry with positions relevant to the project. They
are of different genders, age and experience but none are:
• Under the age of 18
• Unable to consent
As no one was under the age of 18, no CRB check was necessary for the study.
The questionnaire (see Appendix A) was distributed via email, together with an
explanation of what was being investigated and why. In the email the participants
were asked to refer to the Participant’s Information Letter (see Appendix B) attached
for further information about the purpose of the study and an outline of what their role
would be within it. Should they wish to participate, they were asked to fill in and sign
the attached Participant Consent Form (see Appendix C) and email a copy back to
me.
5.1 Participant Information Letter
Within the Participant Information Letter:
 Reassurance is gi ven that the participant’s/company’s reputation will not be at
risk as no names or businesses will be mentioned in the final dissertation and
confidentiality will be upheld at all times.
 Reassurance is given that in order to manage the risk of anonymity; all data
gathered through the study will be saved on an encrypted memory stick and
then destroyed once the project is completed.
 The participant is made aware that the data will not be used for any other
purposes other than to support the recommendations in the dissertation.
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 So as not to put any pressure on the participants to agree to take part in the
questionnaire, the participants are informed that all answers to questions are
entirely voluntary.
 The participants are made aware that they can withdraw from the study at any
time and if they should wish to do so, they should fill in the withdrawal section
of the consent form and email it to me.
 The researchers contact details were provided should the participants have
further questions or wish to withdraw themselves from the study.
 Contact details of the supervisor and for the university were also provided in
case the participants should want to talk to the relevant senior faculty
members.
5.2 Participants Consent Form
Within the Participant Consent Form:
 The participant is made aware that by signing the form he/she was agreeing
to their data being used in the dissertation.
 A withdrawal section at the bottom of the form is left for any participants who
wish to withdraw from the study. Filling in this section would mean their
information would be destroyed and not used in the dissertation.
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5.3 Ethics Tick Sheet
WILL YOUR RESEARCH STUDY? YES NO
1 Involve any external organisation for which separate research ethics clearance
is required (e.g. NHS, Social Services, Ministry of Justice)?
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No
2 Involve individuals aged 16 years of age and over who lack capacity to consent
and will therefore fall under the Mental Capacity Act (2005)?
No
3
Collect, use or store any human tissue/DNA including but not limited to serum,
plasma, organs, saliva, urine, hairs and nails? Contact Dr Matt Bristow.
No
4 Involve medical research with humans, including clinical trials? No
5 Administer drugs, placebos or other substances (e.g. food substances,
vitamins) to human participants?
No
6 Cause (or could cause) pain, physical or psychological harm or negative
consequences to human participants?
No
7 Involve the researchers and/or participants in the potential disclosure of any
information relating to illegal activities; or observation/handling/storage of
material which may be illegal?
No
8 With respect to human participants or stakeholders, involve any deliberate
deception, covert data collection or data collection without informed consent?
No
9 Involve interventions with children under 18 years of age? No
10 Relate to military sites, equipment, weapons or the defence industry? No
11 Risk damage or disturbance to culturally, spiritually or historically significant
artefacts or places, or human remains?
No
12 Involve genetic modification, or use of genetically modified organisms? No
13 Contain elements you (or members of your team) are not trained to conduct? No
14 Potentially reveal incidental findings related to human participant health
status?
No
15 Present a risk of compromising the anonymity or confidentiality of personal,
sensitive or confidential information provided by human participants and/or
organisations?
Yes
16 Involve colleagues, students, employees, business contacts or other individuals
whose response may be influenced by your power or relationship with them?
No
17 Require the co-operation of a gatekeeper for initial access to the human
participants (e.g. pupils/students, self-help groups, nursing home residents,
business, charity, museum, government department, international agency)?
No
18 Offer financial or other incentives to human participants? No
19 Take place outside of the country in which your campus is located, in full or in
part?
No
20 Cause a negative impact on the environment (over and above that of normal
daily activity)?
No
21 Involve direct and/or indirect contact with human participants? Yes
22 Raise any other ethical concerns not covered in this checklist? No

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6.0 Results
The results of the questionnaire are founded on the opinions of 10 professional
within the construction industry that specialise in listed buildings. The analysis for the
results of questions 1 - 4 uses information taken from the chart titled Fig 4.
Chart 1 - What natural insulation materials would you prefer to use?
12.00
10.00
8.00
6.00
4.00
2.00
0.00
The most popular Natural Insulation material was Flax. This choice is
understandable as it is a fairly standard natural insulation product however it is
somewhat surprising that sheep’s wool was not the favourite as it costs nearly the
same as flax but has a better thermal performance. To achieve a U-Value of
0.25Wm2K, flax needs a thickness 170mm yet sheep’s wool only needs a thickness
of 150mm. For the same reason it is surprising cotton was not used by any
participants in the survey. It would make more sense that cork was not chosen as it
is not used in the UK.
The three most popular choices were insulation rolls. What may have affected this
result is the fact most listed buildings cannot have insulation on the walls but are
more likely to have it i n the roof and rolls generally can’t be used on walls. Insulation
rolls may also be more popular because they come in long lengths, which reduce the
amount of sections needed to fill the entire length of a cavity.
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Chart 2 - What mineral insulation materials would you prefer to use?
8.00
7.00
6.00
5.00
4.00
3.00
2.00
1.00
0.00
The most popular Mineral Insulation material was Cellular glass closely followed by
Glass Fibre and Calcium Cilicate Board. This is an unexpected result as glass fibre
has the best thermal performance out of the 3 materials; it is the cheapest alternative
and the most versatile. For this same reason it is surprising stone mineral wool did
not score higher. However glass fibre qui lts are known to slump over time which can
reduce their performance, this may mean the participants were considering the
longevity of the material. It is not surprising that Aerogel was not used by any of the
participants because it is cutting-edge material developed by NASA and it is
therefore very expensive, making its payback period very long.
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Aerogel Calcium
silicate board
Cellular glass Glass fiber Lightweight
expanded
clay
aggregate
Stone
mineral wool
Vermiculite Other

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Chart 3 - What petrochemical insulation materials would you prefer to use?
6.00
5.00
4.00
3.00
2.00
1.00
0.00
Expanded
polystyrene
The most popular Petrochemical Insulation material was Phenolic foam boards. This
is a predictable result as it has a very low conductivity partially due to its foil backing
out and only a thickness of 80mm is needed to achieve a u-value of 0.25Wm2K, so
this is particularly helpful where space is at a premium. Unfortunately this also
means it comes with a higher price tag so it may not necessarily have a short
payback period. It is interesting that phenolic foam boards just like flax cannot be
used as exterior wall insulation. Again this implies that this is not an important
requirement because rarely can it be permitted to install wall insulation on a listed
building.
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Extruded
polystyrene
Phenolic foam
boards
Polyurethane,
polyisocyanurate
board & spray
foam
Recycled plastic
bottle fiber wool
Other

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Chart 4 - What composite insulation materials would you prefer to use?
3.10
3.00
2.90
2.80
2.70
2.60
2.50
As there were only two choices for this question and there were relatively little
participants, the result is not that reliable. Vacuum insulated panels have a much
better thermal performance and are very versatile but because they are quite
sophisticated they are also very expensive.
The case for multifoil’s is the complete opposite, i n fact mutlifoil’s are generally only
meant to be used a supplementary product. Therefore given that the benefits of
multifoil are dependent on what they are used in conjunction with; it would seem that
vacuum insulated panels are the best insulation material in their own right.
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Multi-foils Vacuum insulated panels Other

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Chart 5 - What methods would you most prefer to improve the thermal efficiency of a
cold pitched roof?
4.50
4.00
3.50
3.00
2.50
2.00
1.50
1.00
0.50
0.00
Insulation quilts Insulation batts Loose-fill
The preferred type of insulation was insulation quilts. This conforms to the favourite
insulation materials in the first two questions, as they too came in quilt form. It seems
probable that participants may have made their selection of materials based on the
fact that they come as quilts. This implies that the participants were considering the
ease of use of the insulation material in their assessment and not just their beneficial
properties. This is something to consider when judging the results. It is not surprising
the participants have not used loose-fill insulation as this requires specialists to blow
in the insulation from a pipe.
It could be argued that insulation quilts are the simplest type to install because there
is no need for precise cutting to fit them in to awkward spaces. For example
joists/rafters not being equal distances apart, a common trait in old buildings. Qui lts
are also much easier to manage as they roll up; it is easy to get them in to tight roofs
spaces for example.
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Insulation
Other

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warm pitched roof?
4.50
4.00
3.50
3.00
2.50
2.00
1.50
1.00
0.50
0.00
Insulation above
The preferred method of insulating a pitched warm roof was insulation above the
rafters. This may be because of the reasons stated in the literature review. This
solution minimises the risk of condensation as it keeps the roof structure warm and
there is no necessity for an air gap to provide ventilation.
It may also be the preferred option because most listed that have a habitable room in
the roof space would also have historic plasterwork. This would be destroyed if
insulation were installed between or underneath the rafters. But this threat is taken
away when insulation is installed above the rafters as the roof tiles only need to be
removed and reinstalled after the insulation is fitted. This option is more time
consuming but more likely to get planning approval. Another reason could be
because of increasing popularity in having exposed wooden beams.
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rafters
Insulation below
rafters
Insulation between
rafters
Other

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Chart 7 - What methods would you most prefer to improve the thermal efficiency of
solid masonry wall?
4.50
4.00
3.50
3.00
2.50
2.00
1.50
1.00
0.50
0.00
Internal insulation External insulation Render Other
The preferred method of insulating an external masonry wall was render. This may
be because in most cases the participants have not installed insulation on the
exterior wall of listed buildings for all the reasons mentioned in the literature review.
However, many listed bui ldings have render that may be in bad condition. Therefore
it is very likely that planning consent would be given in these cases to re-render the
building using traditional materials or equivalents.
Internal insulation being the least favoured corresponds with what was stated in the
literature review. Internal insulation prevents the heat inside the bui lding from
warming the masonry. As a result, the temperature of the wall would reach dew point
and moisture will condense inside the wall.
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wattle & daub/lathe & plaster wall?
4.00
3.50
3.00
2.50
2.00
1.50
1.00
0.50
0.00
External render Replacement
The preferred method to upgrade the thermal efficiency of a timber framed wall was
internal insulation. This is at odds with the results for a masonry wall however it still
may be a better alternative than completely removing the panels, which may be of
historic value.
External render probably scored the least as timber framed buildings such as those
of Tudor origin have exposed frames. Therefore rendering it would mean covering up
the character of the building and to remove the render in the future could damage
the structure underneath. However if there are records showing that the structure
was rendered in the past it may be given consent.
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panels
Internal insulation Other

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solid masonry/concrete floor?
4.50
4.00
3.50
3.00
2.50
2.00
1.50
1.00
0.50
0.00
Install a wooden
internal insulation. This was likely to be the highest scorer as it is probably the
cheapest and simplest way of insulating a solid floor. It also causes the least amount
of disruption to the building. It was not likely that the other two methods would be the
most popular as the extra depth would likely affect the skirting and the bottom of
doors.
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floor
Install a carpet Insulation Other

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a suspended timber floor?
5.00
4.50
4.00
3.50
3.00
2.50
2.00
1.50
1.00
0.50
0.00
Draught proofing Insulation
internal insulation. This correlates with the graph for solid floors as once again the
participants have chosen the method that is the cheapest, simplest and has the least
impact on the building. This shows that the participants prefer to try the simplest
methods first before the more invasive methods, perhaps because it may not always
be necessary. It is not surprising the two insulation types scored the same as there is
little difference in benefit between the two.
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batts/boards
Insulation quilts Other

SID: 1108442
a window?
6.00
5.00
4.00
3.00
2.00
1.00
0.00
Install curtains,
shutters or blinds
The preferred method of upgrading the thermal efficiency of a window was to install
curtain, shutters or blinds. This is a predictable result as they offer significant
benefits. They are cheap, probably the most visually acceptable and quick and easy
to install. It is not surprising that slim profile double glazing scored the least as it is a
brand new product that is relatively untested, so it is likely the participants have not
even used it before.
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Install secondary
glazing
Install slim profile
double glazing
Other

SID: 1108442
7.0 Conclusions and Recommendations
7.1 Conclusion
The investigations in the literature review found that there are two major barriers
associated with retrofitting listed residential buildings in order to make them more
thermally efficient. These are the listed building regulations and the risk of decay
from damp. These two barriers are connected as it is the inherent risk of decay from
damp which is why listed buildings are protected by the law.
When proposing an alteration to a listed building, planning permission must be
obtained. It is particularly difficult to get permission to upgrade the thermal efficiency
of a listed building as any alterations could affect its special architectural or historical
significance. However it is up to the relevant local planning body to decide whether
the development is justifiable, given the possible loss or damage to the significance
of the listed building.
Heritage conservation does allow change so long as the heritage value remains
intact. Also because heritage conservation is carried out for the sake of public
interest, it means conservation officers will take in to account the views of the public
when deciding whether to grant permission.
There are many ways a listed building can be thermally upgraded but to get planning
permission, for each method chosen, there should be an investigation in to how the
alterations might affect the building in the present and in the future.
There are two main ways to improve the thermal efficiency of a listed building, either
by insulating the fabric to reduce thermal conductivity or improving air tightness to
reduce thermal convection. The trouble with these methods is they also restrict the
movement moisture in the air and the fabric of the building. Old bui ldings were bui lt
to breathe as the original construction materials are very porous so this means
moisture can easily get trapped in the building, which can lead to damp and
therefore decay.
As the listed building regulations would unlikely allow any alterations that could result
in decay to the bui lding it makes it difficult to improve the thermal efficiency of a
listed building. The best ways to mitigate the risk of damp is to use natural insulation
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SID: 1108442
materials that are more porous than other types so they allow the movement of
moisture through the fabric. The other way is to provide controlled ventilation to allow
the movement of moisture through the air.
The literature review also discovered that the building regulations state, that if
planning consent is given to develop on a listed building then the developer has the
duty to increase energy efficiency as far as is realistically obtainable without
damaging the character or the appearance.
From the results of the questionnaire it seems that insulation quilts were the most
popular form of insulation. One reason this could is that because damp is more
associated with wall insulation, roof insulation and floor insulation may be more
favoured and insulation quilts are generally not used for walls as it would be difficult
to hold it up. Insulation quilt are also easier to install in roofs in general.
For the most part, insulation on external wall was not favoured, which makes sense
given all the problems that can arise from applying it. For floors the participants
generally preferred the cheapest options. This makes sense as it would be a waste
to spend out insulating the floor when its thermal efficiency could be upgraded to
sufficient standard through cheap and simple means, such as draught proofing or
installing a carpet.
7.2 Recommendations
For anyone thinking of altering a listed building to make it more thermally efficient, it
would be advisable to think about how the methods used wi ll affect the building
before asking for planning permission. The kind of methods which are less risky will
be more likely to be given consent. These include simple installations such as carpet
fitting and draught proofing. It would also be beneficial to use the more simple
methods before committing to insulation or other drastic procedures, as it may be
that only simple changes are necessary, saving time and money. For the same
reasons it would be reasonable to focus on areas of the building that lose heat more
rapidly, such as the windows.
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SID: 1108442
However if the decision is taken to use insulation it is always best to choose the most
breathable types, natural insulation is probably the best for this. In order to decide
which material to use, it would be sensible to compare the thermal efficiency of the
insulation with the price, to see how long the payback period wi ll be. Also think about
the most appropriate form of insulation for the structure and where it will be installed.
It may also be worth considering how thick the insulation needs to be to perform at a
reasonable standard. If space is at a premium, it might be worth investigating
insulations that require less depth.
It is important to remember that if the decision is taken to develop a listed building, if
granted planning permission, the developer has the duty to improve the thermal
efficiency as is reasonably obtainable. So the developer has to be committed to
improve every possible aspect of the building. Possible methods that may be given
planning permission were stated in this project. The research also shows the kind of
methods preferred by the professionals, so perhaps the methods that were least
favoured should be avoided.
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SID: 1108442
8.0 Further Research
Further research could include:
 Researching the advantages and disadvantages of different
materials/methods and which ones suit different circumstances. This will
make it simpler to decide what option to take.
 Expanding the investigation to see how energy efficient lighting and
space/water heating systems can reduce the amount of energy used in the
first instance, rather than solely focusing on reducing heat loss. It could also
take in to account the amount of embodied energy produced by different
insulation materials.
 Researching renewable energy sources which could help provide energy for
the building in a sustainable manner.
 Expanding the investigation to provide more general advice on installing
insulation etc. This might include the risks involved and the precautions to
take before making alterations.
 Researching government grants that can be used to fund projects on listed
buildings such as the Green Deal or the Heritage Lottery Fund. This may
make it possible to retrofit a building that would have otherwise fallen in to a
state of disrepair.
 Researching thermal imaging which can be used to find out where most of the
heat loss is occurring in a building. This means the developer could focus on
upgrading these weak spots.
 Expanding the investigation to cover the other categories of bui lding such as
commercial and industrial. This will be important to consider this as larger
buildings require more energy to be heated.
 Case studies to evidence the methods that have been used on different types
of building and how the thermal efficiency was affected. This too wi ll help
justify the option to take for any particular building.
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SID: 1108442
9.0 References
Planning (Listed Buildings and Conservation Areas) Act 1990. London: HMSO.
HM Government, 2010. Approved Document L1B Conservation of Fuel and Power.
[pdf] HM Government.
Available at: <
http://www.planningportal.gov.uk/uploads/br/BR_PDF_AD_L1B_2011.pdf>
[Accessed].
The Society for the Protection of Ancient Buildings (SPAB)., 2013.Old House Eco
Handbook: A Practical Guide for Energy Efficiency & Sustainability. London: Frances
Lincoln Ltd.
The Princes Regeneration Trust (PRT)., 2010. The Green Guide for Historic
Buildings: How to Improve the Environmental Performance of Listed and Historic
Buildings. Norwich: TSO (The Stationery Office).
M.G. Cook., 2009. Energy efficiency in Old Houses. Ramsbury: The Crowood Press
Ltd.
English Heritage, 2012. Energy Efficiency and Historic Buildings. [pdf] English
Heritage. Available at: < https://www.english-heritage.org.uk/publications/energy-efficiency-
48 | P a g e
historic-buildings-ptl/eehb-partl.pdf> [Accessed].
European Commission, 2012. National Library of Guidelines. [online] Available at: <
http://edgar.jrc.ec.europa.eu/overview.php?v=CO2ts1990-2011> [Accessed].
English Heritage, 2014. National Library of Guidelines. [online] Available at: <
http://www.english-heritage.org.uk/> [Accessed].
The Society for the Protection of Ancient Bui ldings (SPAB), 2009. National Library of
Guidelines. [online] Available at: < https://www.spab.org.uk/> [Accessed].
BBC, 2013. National Library of Guidelines. [online] Available at: <
http://www.bbc.co.uk/news/science-environment-24292615> [Accessed].
All illustrations were created by the Author.

SID: 1108442
10.0 Bibliography
The Society for the Protection of Ancient Buildings (SPAB)., 2013.Old House Eco
Handbook: A Practical Guide for Energy Efficiency & Sustainability. London: Frances
Lincoln Ltd.
The Princes Regeneration Trust (PRT)., 2010. The Green Guide for Historic
Buildings: How to Improve the Environmental Performance of Listed and Historic
Buildings. Norwich: TSO (The Stationery Office).
M.G. Cook., 2009. Energy efficiency in Old Houses. Ramsbury: The Crowood Press
Ltd.
English Heritage, 2012. Energy Efficiency and Historic Buildings. [pdf] English
Heritage. Available at: < https://www.english-heritage.org.uk/publications/energy-efficiency-
49 | P a g e
historic-buildings-ptl/eehb-partl.pdf>
English Heritage, 2008. Conservation Principles Policies and Guidance: For the
Sustainable Management of the Historic Environment. [pdf] English Heritage.
Available at: < https:// http://www.english-heritage.org.uk/publications/conservation-principles-
sustainable-management-historic-environment/
conservationprinciplespoliciesguidanceapr08web.pdf>

SID: 1108442
11.0 Appendices
A
Improving Thermal Efficiency in Listed Residential Buildings
Please read the instructions below before commencing the questionnaire:
Please answer questions 1-11 by writing a NUMBER in each box corresponding to your
preferred material(s)/method(s) for improving the thermal efficiency of a listed
residential building. The HIGHEST number will be your MOST preferred and the LOWEST
will be your LEAST preferred. Please put them in order of preference.
You may leave boxes blank if you would never use that particular material/method or
have not heard of it, this includes the boxes labeled ‘Other’. If you can’t pick a
preference between any number of materials/methods you may put the same number
in each box. Please write any comments you may have in the boxes provided.
1- What natural insulation materials would you prefer to use? Please write a number
between 10 and 1 according to your preference.
Cellulose
Cork (expanded)
Cotton
Flax
Hemp
Monolithic lime/hemp mix
Reed board
Sheep’s wool
Wood fiberboard
Other
Comments -
50 | P a g e

SID: 1108442
2- What mineral insulation materials would you prefer to use? Please write a number
between 8 and 1 according to your preference.
Aerogel
Calcium silicate board
Cellular glass
Glass fiber
Lightweight expanded clay aggregate
Stone mineral wool
Vermiculite
Other
C omments -
51 | P a g e

SID: 1108442
3- What petrochemical insulation materials would you prefer to use? Please write a
number between 6 and 1 according to your preference.
Expanded polystyrene
Extruded polystyrene
Phenolic foam boards
Polyurethane, polyisocyanurate board & spray foam
Recycled plastic bottle fiber wool
Other
C omments –
4- What composite insulation materials would you prefer to use? Please write a
number between 3 and 1 according to your preference.
Multi-foils
Vacuum insulated panels
Other
Comments –
52 | P a g e

SID: 1108442
5- What methods would you most prefer to improve the thermal efficiency of a cold
pitched roof? Please write a number between 4 and 1 according to your preference.
Insulation quilts
Insulation batts
Loose-fill Insulation
Other
C omments –
6- What methods would you most prefer to improve the thermal efficiency of a warm
pitched roof? Please write a number between 4 and 1 according to your preference.
Insulation above rafters
Insulation below rafters
Insulation between rafters
Other
Comments –
53 | P a g e

SID: 1108442
7- What methods would you most prefer to improve the thermal efficiency of solid
masonry wall? Please write a number between 4 and 1 according to your preference.
Internal insulation
External insulation
Render
Other
C omments –
8- What methods would you most prefer to improve the thermal efficiency of a wattle
& daub/lathe & plaster wall? Please write a number between 4 and 1 according to
your preference.
External render
Replacement panels
Internal insulation
Other
C omments –
54 | P a g e

SID: 1108442
9- What methods would you most prefer to improve the thermal efficiency of solid
masonry/concrete floor? Please write a number between 4 and 1 according to your
preference.
Install a wooden floor
Install a carpet
Insulation
Other
C omments -
10- What methods would you most prefer to improve the thermal efficiency of a
suspended timber floor? Please write a number between 4 and 1 according to your
preference.
Draught proofing
Insulation batts/boards
Insulation quilts
Other
Comments –
55 | P a g e

SID: 1108442
11- What methods would you most prefer to improve the thermal efficiency of a
window? Please write a number between 4 and 1 according to your preference.
Install curtains, shutters or blinds
Install secondary glazing
Install slim profile double glazing
Other
C omments –
Thank you for taking the time to complete this questionnaire, it is very much appreciated.
56 | P a g e

SID: 1108442
B
57 | P a g e
Taylor Betts
7 Stanford Road
Canvey Island
Essex
SS8 0DG
Mobile: 07472 686104
Email: taylor.betts@student.anglia.ac.uk
26th
January 2014
Dear Sir or Madam
My name is Taylor Betts and I am studying Construction Management at Anglia Ruskin
University. I am undertaking a survey investigating the barriers to improving energy
efficiency in listed residential buildings. Your experienced opinion is of great interest to me.
I have designed a questionnaire hoping you will be able to aid me in this study. No names or
businesses will be mentioned and confidentiality will be upheld at all times. I would be very
appreciative if you could find the time to fill in the questionnaire and send it back to me.
Thank you.
If you are willing to assist me, please would you mind signing the participant consent form
and either email or post it to me for the study to go ahead. All funding is financed by me.
Agreement to participate in this research should not compromise your legal rights. All
results of the study will be analysed and used to support the recommendations stated in the
dissertation. If you wish to withdraw from the study, please fill in the withdrawal section of
the consent form and contact me at any time so I can remove your answers from the survey.
My tutor Sunny Nwaubani is available for any further information.
(Email: sunny.nwaubani@anglia.ac.uk)
Thanking you in advance for your help.
Yours Faithfully,
Taylor Betts

SID: 1108442
C
Participant Consent Form
NAME OF PARTICIPANT:
Title of the project: “Investigating the Barriers to Improving Energy Efficiency in Listed Residential
Buildings”
Main investigator and contact details: Taylor Betts 07472 686104 taylor.betts@student.anglia.ac.uk
Members of the research team: Taylor Betts, Sunny Nwaubani
1. I agree to take part in the above research. I have read the Participant Information Sheet which
is attached to this form. I understand what my role will be in this research, and all my
questions have been answered to my satisfaction.
2. I understand that I am free to withdraw from the research at any time, for any reason and
without prejudice.
3. I have been informed that the confidentiality of the information I provide will be safeguarded.
4. I am free to ask any questions at any time before and during the study.
5. I have been provided with a copy of this form and the Participant Information Sheet.
Data Protection: I agree to the University1 processing personal data which I have supplied. I agree to
the processing of such data for any purposes connected with the Research Project as outlined to me.
Name of participant (print)………………………….Signed………………..….Date………………
Name of witness (print)……………………………..Signed………………..….Date………………
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YOU WILL BE GIVEN A COPY OF THIS FORM TO KEEP
--------------------------------------------------------------------------------------------------------------------------
If you wish to withdraw from the research, please complete the form below and return to the main
investigator named above.
Title of Project:
I WISH TO WITHDRAW FROM THIS STUDY
Signed: __________________________________ Date: ____________________
1 “The University” includes Anglia Ruskin University and its partner colleges

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