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DT175a Dissertation
Retrofit of a 19th
Century Building ~A strategy for the thermal retrofit of Cuilín House~
(Submission date 11th May 2012)
DT175a – Module: ARCH4258 – Final Year Dissertation
~ Conor Sweeney ~
C08731136
Supervisor: Cathy Prunty
Total Words: 11,612
Main Body: 8,200
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Abstract
This dissertation contrasts two retrofit proposals to be applied to an historic protected
structure in some disrepair. The first using synthetic materials and minimalist
interventions to the existing fabric, the second with a more rounded and intensive
thermal retrofit sensitively tailored to the intricacies of a19th century building’s
dynamics. A strategy for renovation with a mind towards both conservation and
thermal efficiency upgrading is put forward and evaluated against the baseline
proposal, and evaluated from breathability and conservation perspectives, as well as a
detailed analysis of the overall effect both approaches have on the thermal efficiency
of the structure.
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Declaration
I hereby declare that the work described in this dissertation is, except where otherwise stated, entirely my own work and has not been submitted as an exercise for a degree at this or any other university.
_________________________
Student Name
2012
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Acknowledgements
I’d like to thank Sima, Sarah, Dave and all the Studio Staff for their encouragement,
interest and expertise this year, my thesis supervisor Cathy Prunty for her unerring
eye and appreciation for detail, the staff and students of the School of Architecture,
for an interesting, engaging, fun and incredibly busy 4 (or more) years and lastly and
most of all my family for all their support and help, and for giving me the swift kick
up the backside I needed to get my act together to get to this point.
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Table of Contents
Chapter 1 Introduction................................................................................................ 9
1.1 Preamble & Context ............................................................................................ 9
1.2 Aims of the Research ........................................................................................ 10
1.3 Objectives ........................................................................................................... 10
1.4 Cuilín House ..................................................................................................... 11
1.5 Initial Unit 01 Proposal .................................................................................... 12
1.6 Methodology ...................................................................................................... 14
Chapter 2 – Literature Review ................................................................................. 15
2.1 Traditional Buildings - General ....................................................................... 15
2.1.1 Traditional Solid Walls ............................................................................... 15
2.1.1 Timber Sash Windows ................................................................................ 17
Chapter 3 – Fabric Retrofit & Refurbishment ....................................................... 19
3.1 External Walls ................................................................................................... 19
3.1.1 Current Condition ....................................................................................... 19
3.1.2 Condensation Risk Analysis ....................................................................... 19
3.1.3 Breathable Construction.............................................................................. 21
3.1.4 Insulation Selection ..................................................................................... 22
3.1.5 Proposed Intervention ................................................................................. 24
3.1.6 Resultant Wall U-Value .............................................................................. 26
3.2 Replacement Ground Floor .............................................................................. 27
3.2.1 Current Condition ....................................................................................... 27
3.2.2 Initial Unit 01 Proposal ............................................................................... 27
3.2.3 Proposed Intervention ................................................................................. 28
3.2.3 Resultant U-Value ....................................................................................... 30
3.3 Existing Cut-Timber Collar Roof ..................................................................... 31
3.3.1 Current Condition ....................................................................................... 31
3.3.3 Initial Unit 01 Proposal ............................................................................... 32
3.3.3 Proposed Intervention ................................................................................. 32
3.3.4 Resultant U-Value ....................................................................................... 34
3.4 Existing Timber Sash Windows........................................................................ 35
3.4.1 Current Condition ...................................................................................... 35
3.4.2 Initial Unit 01 Proposal ............................................................................... 35
3.4.3 Proposed Intervention ................................................................................. 35
3.4.4 Resultant U-Value ....................................................................................... 37
Chapter 4 – New Construction ................................................................................ 38
4.1 Circulation Atrium ............................................................................................ 38
4.1.1 Atrium Structural Glass Walls & Roof ....................................................... 38
4.1.2 Radiant Concrete Floor ............................................................................... 39
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Chapter 5 – Thermal Comparison ........................................................................... 40
5.1 Introduction ....................................................................................................... 40
5.1.1 General ........................................................................................................ 40
5.1.2 Heat Losses Generally ................................................................................ 40
5.1.3 Steady State Heat Loss Calculation ............................................................ 41
5.2 Total Transmission Heat Loss .......................................................................... 44
5.3 Total Ventilation Heat Loss .............................................................................. 46
5.4 Total Heat Loss & Demand .............................................................................. 47
Chapter 6 - Conclusion .............................................................................................. 48
Appendix A – U Value Calculations ......................................................................... 51
Unit 01 External Wall Proposal .......................................................................... 52
Rebuilt Suspended Ground Floor ........................................................................ 52
Thermal Retrofit of External Wall ....................................................................... 53
Unit 01 Proposed Roof Refurb ............................................................................. 54
Retrofitted Cut Timber Roof................................................................................ 55
Internal Wall Type 1 (450 Solid Brickwork) ........................................................ 56
Appendix B – BuildDesk Condensation Analyses ................................................... 57
Appendix C – Fabric Heat Loss Calculations ......................................................... 60
Appendix D – Overall Unit 01 Proposal .................................................................. 66
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Table of Tables
Table 1: U-Value Calculation of Unit 01 Wall Proposal 24
Table 2: U-Value Calculation of Proposed Suspended Timber Floor 30
Table 3: U-Value Calculation for Proposed Roof Retrofit 34
Table 4: Possible Actions for thermal upgrade of traditional sash windows and their
resultant U-Value. 37
Table 5: U-Value Calculation for New-Build Concrete Floor @ Atrium 39
Table 6: Summary of Element U-Values. 40
Table 7: Design Internal & External Temperatures 43
Table 8: Example Heat Loss Calculation for external wall in one room. 44
Table 9: Transmission Heat Loss by Space – Unit 01 44
Table 10: Transmission Heat Losses by Space – Deep Retrofit 45
Table 11: Calculation Table of Ventilation Heat Losses – Shallow Retrofit 46
Table 12: Calculation Table of Ventilation Heat Losses – Deep Retrofit 46
Table 13: Total Heat Losses 47
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Table of Figures
Figure 1: Cuilín House and surrounding structures ................................................ 11
Figure 2: Roof Plan of Cuilín House Existing .......................................................... 13
Figure 3: Roof Plan Showing Alterations ............................................................... 13
Figure 4: Section Showing Existing Arrangement .................................................. 13
Figure 5: Section Showing New Arrangement ....................................................... 13
Figure 6: Existing Wall Inner Face: Unplastered section......................................... 19
Figure 7: Sketch of insulation board & external wall dabbing ................................ 19
Figure 8: Wool Strand Diagram ............................................................................. 22
Figure 9: The principle of insulation performing a hygroscopic buffering function,
storing and diffusing moisture from vapour ingress. ..................................... 23
Figure 10: The problems associated with introducing vapour control principles to a
traditional solid wall. .................................................................................... 23
Figure 11: Diagram of Retrofit Wall Buildup. ........................................................ 24
Figure 12: Fractional Areas of Bridging through the insulation and batten plane. .. 26
Figure 13: Existing Floor boards ............................................................................ 27
Figure 14: Missing Floor boards and exposed subfloor / dwarf walls ..................... 27
Figure 15: Unit 01’s Floor Build-Up Proposal ......................................................... 27
Figure 16: Joists and Dwarf Wall separated from External Wall ............................. 28
Figure 17: Proposed Floor Construction – through Joists ....................................... 28
Figure 18: Proposed Floor Construction – through Dwarf Wall .............................. 28
Figure 19: Proposed Retrofit Subfloor Vents & External French Drain ................... 29
Figure 20: Section of Upper Storey ....................................................................... 31
Figure 21: Existing Roof Rafters & Collars exposed internally ................................ 31
Figure 22: 3-D showing existing eaves and roof build-up ....................................... 32
Figure 23: Section showing existing eaves arrangement ....................................... 32
Figure 24: Proposed extension of eaves to allow soffit ventilation ........................ 32
Figure 25: Section through proposed roof construction ........................................ 33
Figure 26: Section through Joists .......................................................................... 33
Figure 27: Recessed window with architrave and panelling .................................. 35
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Figure 28: Flush Sash Window .............................................................................. 35
Figure 29: Draughtproofing measures for sash windows ....................................... 35
Figure 30: Jamb detail: flush window with secondary glazing ................................ 36
Figure 31: Jamb detail: recessed window with secondary glazing .......................... 36
Figure 32: Heat Camera Image showing the heat lost through traditional sash
window (right) and one with secondary glazing (left). ................................... 36
Figure 33: Traditional Sash ................................................................................... 37
Figure 34: 3D of Atrium siting within Cuilin House ................................................ 38
Figure 35: Triple paned structural glass ................................................................ 38
Figure 36: New Build Atrium Floor ........................................................................ 39
Figure 37: First Floor Plan with internal ................................................................ 43
Figure 38: Ground Floor Plan with internal ........................................................... 43
Figure 39: Fractional Areas of materials in the cross-battened wall/roof ............... 51
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Introduction
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Chapter 1
Introduction
1.1 Preamble & Context
Energy efficiency in our existing building stock is becoming more and more a
concern as European Union member states commit themselves to newer and ever
more ambitious energy saving and emission reduction targets. By 2020 Ireland is
required under the EU’s Europe 2020 Strategy, as one of its five key aims, to reduce
its greenhouse gas emissions by 20% and to achieve a 20% increase in energy
efficiency over the whole economy compared to 1990 levels.
Europe uses 40% of its energy in heating and cooling its buildings, as such it is an
obvious and necessary goal to approach new refurbishment and restoration projects
with a goal to improving thermal efficiency.
Department of the Environment statistics indicate that over 10 per cent of the existing
dwelling stock in Ireland was constructed pre-1919, and thus fall far below modern
standards of thermal efficiency and thus consume more energy to heat. As the
greenest building is one that has already been built, in terms of embodied energy,
retrofitting historic and traditional buildings to a higher standard of thermal efficiency
is an exercise in sustainability and conservation, as the best way to ensure the comfort
required for their continued use and thus survival.
That being said an appropriate balance must be maintained between building
conservation and energy conservation, due respect must be given to the traditional
elements of older construction and their particular dynamic in any intervention, the
approach taken must balance these aims. The interventions proposed for this protected
building are directly informed by the quality and extent of remaining historical
features in their original positions and are intended as a guide for protected buildings
in a similar state of degradation and historical erosion.
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Introduction
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1.2 Aims of the Research
This dissertation aims to propose a thermal retrofit strategy for Cuilín House that will
balance the concerns around the conservation of a culturally significant building, and
the desire for thermal and thus energy efficiency.
This paper will explore and analyse the considerations involved in retrofitting and
refurbishing a 19th century building and to suggest appropriate interventions, informed
by best practice. These interventions will be designed to improve thermal
performance without disrupting or damaging the integrity of the existing fabric, and
preserving the buildings historic features.
1.3 Objectives
This paper will explore the issues and possible problems involved in executing a
thermal intervention to an historic building by;
• Reviewing existing guidance documents on the subject
• Applying thermal retrofit interventions through detail design to the study
building, informed by guidelines and best practice.
• Suggesting technological solutions to improving thermal performance while
maintaining fabric integrity and that of historical features.
• Comparing the finished project to an earlier retrofit proposal of the building in
terms of thermal performance.
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Introduction
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1.4 Cuilín House
The sample older building used in this study is Cuilín House, located off Hampstead
Avenue in the mature wooded surrounds of the old Albert College in Glasnevin
Dublin 9.
The building was originally constructed to house the operator of the model farm in
that location, which served as an educational institution from the early 19th century
until the latter half of the 20th. The model farm was among the first of its kind in
Europe and attracted visitors as notable as Prince Albert of the United Kingdom, for
whom the college is named, and the son of Napoleon I of France, as it was seen as a
new departure in the education of farmers and farm workers. The House itself has
been the subject of a number of extensions and demolitions to both its core
arrangement and surrounding structures and is currently at the south-west corner of a
quadrangle of outbuildings of varying ages and levels of use.
Today the complex is used by the Dublin City Council (DCC) Parks Department;
however the house itself is currently in a state of disuse and considerable disrepair. It
is a protected structure not for its intrinsic architectural merit, but for the social and
cultural importance it attained in its role as a pathfinder in the realm of agricultural
education in Ireland and Europe.
Figure 1: Cuilín House and surrounding structures
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Introduction
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1.5 Initial Unit 01 Proposal
The proposed demolitions and extensions contained and used in this study are a result
of the development project undertaken by myself and my colleagues in Unit 01, as
part of our Technical Design Studio thesis project in our final year.
I have isolated the original 1830’s house proper for the purposes of this study and
disregarded works to the ancillary buildings. The works proposed by this earlier
project for the main house include the demolition of lean-to single story concrete
structure at the rear (east elevation) of the main house, and the front porch (west
elevation), both of which are later additions to the building.
The largest proposed changes involved the removal of the central part of the east
façade facing into the quadrangle and replacing it with a glazed atrium to perform as a
circulation area, in terms of this study a new modern intervention interacting with a
much older surrounding building.
The overall use of Cuilín House will change to that of office space for the DCC at
ground level and the provision of an exhibition space and office accommodation at
first floor level for use of the community. Full details and explanatory drawings of
Unit 01’s proposals are to be found in Appendix
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Introduction
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Figure 2: Roof Plan of Cuilín House Existing Figure 3: Roof Plan Showing Alterations
Figure 5: Section Showing New Arrangement Figure 4: Section Showing Existing Arrangement
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Introduction
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1.6 Methodology
The structure of this dissertation is relatively straightforward – reading and comparing
texts such as guidance notes, case studies and other research to inform an approach to
detailing specific elements of the fabric of the building.
In summation, the methodology applied to compiling this paper is as follows:
• Secondary Research: Reading guideline texts and prior research into the areas
directly related to the applications (i.e. case studies and best practice
documents in the field of solid wall insulation.)
• Secondary Research: Reading papers around the concepts and philosophy
underlying the interventions chosen (i.e. the concept and dynamic of
breathability in construction)
• Primary Research: Use of computer programmes for evaluation
• Primary Research: Adapting and applying technologies informed by secondary
research reading to details of prior survey of building.
• Primary Research: Evaluation of proposals through attaching thermal values to
their buildip (i.e. U-Valuation)
• Primary Research: Evaluating the dissertation hypothetical intervention’s
values to those of the baseline Unit 01refurbishment proposal using an
empirical model of comparison (i.e. the heat loss calculation).
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Literature Review
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Chapter 2
Literature Review 2.1 Traditional Buildings - General
2.1.1 Traditional Solid Walls
Traditional solid walls are inherently different creatures when it comes to the addition
of internal or external insulation. Condensation risk and interrupting their natural
dynamic is a huge issue in any consideration. There are a number of guidelines and
studies that deal with the complications around internally insulating walls of this
nature.
Guidance from English Heritage (2010) holds that in a traditional wall, the build-up
often contains a variety of materials with different performance characteristics and the
presence of “voids, irregular bonding patterns and concealed timbers” can complicate
any understanding of how energy and moisture interact with the structure. The guide
warns against the reliability of modern theoretical calculations and analytical
computer programmes in the design of a thermal upgrade, and if such a method is
used then “performance should be closely monitored after installation in case of
problems occurring. This guide strongly warns against the use of modern synthetic
insulation materials, as the natural materials in the walls are designed to “breathe”, or
exchange moisture vapour between outside and in. Vapour barriers and other
impermeable materials are to be avoided as they may trap and hold moisture in the
wall.
The UK’s Energy Saving Trust guidelines on the refurbishment of solid-walled
houses (2006) maintains that best practice is to take a U-Value of 0.3W/m2K to be the
goal of internally insulating. However this source seems to deal with more modern
brick and concrete solid walls and much of the guidance is around the idea of a
vapour control layers and synthetic materials, contravening the guidance above.
An article on the subject of breathing in Self Build’s online edition (Morgan, 2008)
expands on the traditional concept of the breathing building versus the modern idea of
“we dare not let moisture into the fabric of our buildings”. Traditional walls of stone
and brick permitted the movement of moisture through and around them and, the
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author states, experience has taught us “modern responses – based on blocking the
passage of moisture where it suits us – it tends not to work.” Morgan also warns
against synthetic insulants in favour of “hygroscopic” materials to effectively store
and buffer moisture in its vapour form - both managing wall moisture content and
passively controlling internal humidity.
Expanding on the role of the wall regulating damp and moisture, the Department of
the Environment’s Guide to Energy Efficiency in Historic Buildings (2010) describes
the way traditional wall materials’ porosity allowed moisture to be absorbed, stored
and later released, echoing other sources. Actual water from rain was absorbed but
owing to the thickness of the wall never made it directly through, where moisture
vapour passed through depending on pressure either side. Repointing may be
necessary and measures taken to avoid rising damp. The guide also pointed out that
chemical DPC’s are unreliable in any rubble filled wall, as the presence of voids can
negate it’s effects.
The Society for the Protection of Ancient Buildings, in their Control of Damp
publication (SPAB, 2009) mentions sheep’s wool and cellulose as effective natural
hygroscopic materials that can help reduce existing condensation issues, as well as
improving thermal performance. This was the first evidence I’d encountered of
internal insulation having a directly positive effect condensation risk as opposed to
merely being designed so as not to have a negative effect. Since the opinion seems to
be that modelling software cannot be relied upon, it will be important to design the
retrofit with a high level of tolerance to any negative condensation effects.
Significantly, one of the only studies that aims to refute the claims made around the
importance of breathability as a consideration in insulation comes from a white paper
produced by Cambridge Architectural Research (2009) commissioned by a synthetic
insulation manufacturer, Kingspan. In the study, they aver that ventilation accounts
for 95% of the vapour transfer from a house with breathable walls and thus the
breathability of insulation products is “at best a side show,in reality… a complete red
herring”. The study claims that as long as the air changes in a volume are above 0.5/h,
condensation (on surfaces) cannot occur, and that all but the most airtight buildings
exceed this.
However, Neil May of Natural Building Co. in his direct rebuttal of the Kingspan
paper (May, 2009) explains that the paper did not deal with the two areas where
breathability is vital: in the case of fabric health where there are building faults, and
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human health through the prevention of moulds and the buffering of internal
humidity. These would seem to be the most directly related issues with this project
and thus confirms the previous sources in that it would be wisest to go with a natural
breathable insulant product with a hygroscopic buffering or storage ability to
compensate.
2.1.1 Timber Sash Windows
Traditional timber sash windows, originally developed in France, Holland and
England in the 17th century, were the most common window type in Ireland for almost
300 years, up to the mid-20th century.
The Department of the Environment, Heritage and Local Government’s Conservation
Guidelines for Windows (DoEHLG, 1996) warn against well-intentioned but poorly
executed replacement windows in refurbishment projects and in cases were a
replacement is necessary, the advice is to copy another window in the building, or
from another building of the same age, as the design and profile of items like the
glazing bars and the presence of horns changed over time. The guidelines warn
against sealing windows hermetically, as condensation is sure to occur. The
guidelines strongly favour the concept of secondary windows as the “most
satisfactory solution to thermal performance”, but suggest the members be painted a
dark colour and placed so as to be concealed behind glazing bars and meeting rail.
English Heritage’s “Framing Opinions: 7 – Timber Sash Windows” (English
Heritage , 1997) states that the reason for the continuing integrity of centuries old
windows lies in the fact the wood is from the heart of the tree, whereas 60’s and 70’s
windows were sapwood, which is permeable and attractive to fungi. The paper
advices anyone looking to maintain or upgrade their sash windows to look for key
points; signs of structural movement deforming the opening and damaging the
window, evidence that the pointing of the frame to the wall reveal is cracked, loose or
missing, exposing the sash box to moisture, difficulty opening the sash could be
caused by overpainting, broken sash cords, seized up wheels – a full health check is
required.
“Framing Opinions:1: Draughtproofing and Secondary Glazing” (English Heritage,
1994) somewhat disagrees with the guidance from the DOE around secondary glazing
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and double glazing – stating that only about 20% of a buildings heat is lost trhough
windows and most of this through infiltration from improper draught proofing. This
paper seems to be out of date though, only describing secondary glazing as a screen
one can remove when not wanted. This guide comes with valuable drawings on how
to detail a weather proofing intervention to a timber sash.
Guidance on historic windows from the Northern Ireland Environment Agency (NIA,
2010) also mentions the English Heritage finding that 90% of window heat loss is due
to draught and finds therefore that draughtproofing is the most effective form of
insulating historic windows, ruling that double glazing is unneccessary. The booklet
states that higher again insulation from sound and cold can be provided with
secondary glazing and counsels that should rot be found, it may only be localised and
the affected areas removed and spliced with healthy members. In regard to secondary
glazing, the concept of reversibility is important, that the unit can be removed if
desired at a later date.
Historic Scotland’s “Sash & Case Windows” guidance document (Historic Scotland,
2008) recommends against fitting proprietary trickle vents into slots cut in the rails of
sash windows, and instead suggests the chamfering the outside edge of the top sash
and insertion of an adjustable grille on the inside and a fixed grilled on the outside to
allow ventilation over the top.
Historic Scotland’s guidelines for “Energy Efficiency in Traditional Homes” (Curtis,
2008) gives tables on a range of options for improving the thermal performance of
sash windows, giving resultant U-values gained through laboratory testing.
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Fabric Retrofit & Refurb
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Chapter 3
Fabric Retrofit & Refurbishment
3.1 External Walls
3.1.1 Current Condition
The walls currently appear to be in good
condition externally, aside from needing
some repointing work; they are faced in
cut limestone. Internally the plaster is
missing in many areas exposing the brick
inner facing. As has been said, the
internal composition is in some doubt
over whether or not there is a rubble core,
however the thickness of 470-550 would
imply its presence.
3.1.2 Condensation Risk Analysis
Despite the guidance around condensation risk analysis computer programmes being
unsuitable, I put this to test and was immediately aware that I was dealing with a lot
of unknowns re: the internal makeup of the walls. The software, Builddesk U
calculates condensation risk based on
methodology in BS EN ISO 13788:2002,
which is only reliable “for constructions
containing solely homogeneous layers
(unbridged layers)” – this immediately ruled
out this project due to first and ground floor
joists being embedded in the wall.
More from a curiosity and illustrative point of
view I ran a number of simulations around
Figure 7: Sketch of insulation board &
external wall dabbing
Figure 6: Existing Wall Inner Face:
Unplastered section
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installing a synthetic non-breathable insulant (polyurethane board) internally with a
plasterboard finish (full results in Appendix B).
The results showed that a 20mm layer of polyurethane board would pass the
assessment, but with the proviso that although condensation occurs, the condensate is
expected to evaporate during the summer months. Anything thicker than 20mm
resulted in a fail, as condensate would not completely evaporate and degradation
could occur. As 20mm would only provide a U-value of 0.79W/m²K, this was
insufficient.
Predictably the addition of a vapour barrier (0.6mm polyethylene) on the insulations
warm side or a foil backing to the plasterboard mitigated this problem - allowing
levels of the insulation beyond 100mm. While this is potentially possible in a new
build where joints, bridges and perforations are under a measure of control, it is
wholly inappropriate for a retrofit to an existing building. As Chris Morgan for
SelfBuild writes, “It is common, if not ubiquitous that vapour barriers are penetrated
dozens if not hundreds of times on each build” (Morgan, 2008), these would
constitute pinch-points for interstitial condensation, where the areas around the breach
would bear proportionately much more moisture than the rest of the wall which is
protected. The embedded joists and adjoining internal walls would undoubtedly
experience this increased moisture load too, potentially leading to a structural failure
(May, 2005).
This experiment demonstrates that applying modern doctrines of vapour-impermeable
material and constructions with no thought to the existing walls dynamics could lead
to serious structural and performance issues later.
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3.1.3 Breathable Construction
The actual construction of Cuilín House’s is unclear, but the consensus among the
teams surveying was that it was most probably a limestone faced, rubble-cored
construction with a brick inner face. The quality of the stonework and protected
nature of the building prohibits the use of external insulation solutions and internally
insulating a traditional solid wall requires many considerations around disruption of
moisture movement and risks exacerbating surface and interstitial condensation
problems.
The approach taken in this research is one of breathability, using a natural insulation
material capable of buffering the moisture in the wall in its vapour form and in the
form of condensate, storing it for when weather conditions permit evaporation.
Breathability means that a wall of such thickness working as intended has the ability
to dry and keep itself damp free, the thickness is such that actual water does not
penetrate all the way through the structure, but soaks through the external limestone
layer, particularly through the porous lime mortar, wherefrom it in turn evaporates.
The rubble core acts as a buffer, intending water to pass down its length rather than
passing directly into the internal spaces.
Breathability in the context of external walls is something of a misnomer as it sounds
like it implies air-permeability, a more accurate term would be that the wall sweats
moisture vapour – a sweating wall (Morgan, 2008). The concept is that warm air or
heat will always seek to balance itself and the occupied internal environment of a
building will more often than not contain more moisture vapour than the colder
outside air. This creates an out-flowing dynamic that moisture vapour will tend
towards the low pressure outside through a vapour-open wall. Should interstitial
condensation or other damp-related problems (a retrofit DPC is impractical) occur, the
intervention to the wall will be so designed as to absorb and store the moisture until
evaporation conditions area reached once again.
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3.1.4 Insulation Selection
The prime actor in this concept of buffering internal moisture until conditions permit
it’s release into the atmosphere will be the internal insulation lining. The material will
be required to act as a hygroscopic buffer, absorbing excess moisture and releasing it
when the time is right, as well as allowing moisture vapour from both inner and
external environments pass through it to maintain internal environmental balance.
In this context, I have specified Sheep’s Wool as the sole insulating product for use in
the project – wall, floor and roof.
Recommended for use in traditional
solid walled interventions (SPAB,
2009), wool is a naturally hygroscopic
material. The exterior layer of a wool
fibre is water resistant, while it’s inner
layer is ‘hydrophilic’ (water-loving),
meaning the material can absorb up to
30% of it’s weight in moisture without
feeling damp to the touch, and up to
40% of it’s dry mass without
compromising it’s thermal
performance. Significantly though,
when wool absorbs absorbs moisture from the air, it generates a small amount of heat,
known as the ‘heat of sorption’ (Irish Eco Homes, 2010) this warmth, while not
noticeable inside the building, maintains the temperature above dew-point in damp
conditions preventing interstitial condensation from occuring.
These characteristics make sheep’s wool an appropriate choice for this project, as it
assists moisture and vapour transit through the fabric, rather than attempting to disrupt
and contain it, restricting the walls existing breathable dynamic.
Figure 8: Wool Strand Diagram
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Figure 10: The problems associated with
introducing vapour control principles to a
traditional solid wall.
Figure 9: The principle of insulation performing
a hygroscopic buffering function, storing and
diffusing moisture from vapour ingress.
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3.1.5 Proposed Intervention
The baseline model of comparison, the works proposed in the Unit 01 project,
specified the walls to be repointed externally, internally stripped of remaining plaster
and thoroughly cleaned and re-finished in new lime plaster. This resulted in a U-
Value of 1.44W/m²K.
Unit 01 Proposed Wall U-Value
Layer Thickness (m) Conductivity Resistance
Internal
Surface - - 0.13
Plaster 0.018 0.8 0.02
Clay Brick 0.21 0.77 0.27
Limestone 0.29 1.26 0.23
External
Surface - - 0.04
0.70
Total Element U-Value: 1.44
Table 1: U-Value Calculation of Unit 01 Wall Proposal
Repointing of Lime Mortar
Before mixing it is important that the colour of sand matches the original as much as
practicable and that the mix contains as high an amount of lime as necessary to
achieve the level of permeability to affect evaporation of moisture from the wall.
Figure 11: Diagram of Retrofit Wall Buildup.
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Fabric Retrofit & Refurb
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1. Internal Lime Plaster
The internal brickwork surface of the wall is to be re-finished in a lime mortar for the
Unit 01 project and I decided to retain this element for my retrofit proposal, so as to
ensure an even surface for battening. Also from a conservation perspective, a lime
plaster will be a beneficial remnant should the thermal component of the retrofit
require reversing.
The plaster is to be 2-coat as the brick surface is relatively flat. The first coat is an 8-
10mm haired mix of ratio 1:2.5 lime and sand to be scoured and dried for up to three
weeks. Atop this is an 8mm devil or nail coat, performed with a trowel with
projecting nails at each corner to form a key for the finish, which is a thin 2mm 1:1
mix lime:sand to be skimmed smooth.
2. Insulating & Battening:
A batten and counter battening layer is specified to hold the insulation layer –
composed of a vertical series of 50x50mm battens at 400 centres screwed through the
plaster into the brickwork using appropriate sized rawl plugs at 250mm centres. The
counter battening is a horizontal series of 50x50mm battens at 400 screwed to the
vertical. Between each series of battens a 50mm batt of sheep’s wool is tension fitted
ensuring no gaps or room for sagging.
3. Diffusion Membrane:
A polyethylene copolymer membrane is taped to internal face of the battening, this
membrane is a humidity variable diffusion material, regulating the maximum amount
of water vapour that can be transmitted through to the wall at times of high internal
humidity, while still allowing the structure to breath within tolerances – it’s porosity
is selected to match that of the sheep’s wool.
4. Plasterboard:
12.5 Gypsum plasterboard is fixed to the internal battens with 40mm roundhead
galvanised steel plasterboard nails at 150mm centres, to be skimmed and painted using
strictly water-based paint (there is some debate over the use of matt and emulsion
paints and their vapour openness (May, 2005).)
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Fabric Retrofit & Refurb
26
3.1.6 Resultant Wall U-Value
It should be noted that there is a health warning
around U-valuating such an old wall, as
assuming homogenous layers and no air gaps is
unreliable. However the contrast from the Unit
01 proposal to existing forms a basis from which
to make before and after comparisons.
The U-value calculation took into account the
bridging from both sets of battens by using
fractional areas, a result of 0.33W/m²K was
found, above the Part L requirement of
0.27W/m²K but well below the requirements for
a material change of use of 0.6W/m²K and an
80% improvement on the Unit 01 proposal.
Figure 12: Fractional Areas of Bridging
through the insulation and batten plane.
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Fabric Retrofit & Refurb
27
Figure 14: Missing Floor boards
and exposed subfloor / dwarf walls
3.2 Replacement Ground Floor
3.2.1 Current Condition
The existing suspended timber ground floor is
heavily decayed and entirely missing in some
areas of the house. As was common in the early
19th century, the subfloor was ventilated by the
internal spaces, as opposed to external vents, and
consisted of exposed earth (DOE, 2010). It is
proposed to completely replace the entire floor.
3.2.2 Initial Unit 01 Proposal
The specified replacement floor in the Unit 01
project consisted of an entirely new heavily
synthetically insulated radiant concrete floor.
While this had high thermal performance
credentials (0.14W/m²K), it was at variance with
the traditional breathable nature of the
surrounding structure. It is highly probably that
the subfloor, while only ventilated from the
internal spaces, performed a drying function on the external wall and it was therefore
my judgement an upgraded ventilated suspended timber floor system was more
appropriate for this project.
Figure 15: Unit 01’s Floor Build-Up Proposal
Figure 13: Existing Floor boards
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Fabric Retrofit & Refurb
28
3.2.3 Proposed Intervention
The overall deteriorated state of the existing floor presents
an opportunity to eliminate a cold bridge; by using new brick
honeycombed dwarf walls to set the new floor timbers back
from the wall surface. This will protect the timber from
moisture damage and allow the wall insulation and floor
insulation to meet and provide a more complete envelope.
Sheep’s wool is specified to be packed between joists and
around the perimeter.
1. Retrofit Subfloor & Drainage
The exposed earth subfloor was excavated to a level of approximately 400mm below
original subfloor height, lined in well compacted hardcore and a 100mm concrete
subfloor slab was poured. As this brought the subfloor level to below that of the
external ground level, a French trench drain has been specified. 300mm wide, the
depth is determined by the depth of the foundations - so as not to jeopardise
foundation stability, the bottom of the trench cannot go below a figurative 45˚ line
drawn from the top of the foundation (SPAB, 2009).
Figure 16: Joists and Dwarf Wall
separated from External Wall
Figure 17: Proposed Floor Construction –
through Joists Figure 18: Proposed Floor Construction –
through Dwarf Wall
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Fabric Retrofit & Refurb
29
Figure 19: Proposed Retrofit Subfloor Vents & External French Drain
2. Subfloor Ventilation
As stated, the original earthen subfloor was unventilated, which is not uncommon in
older buildings. As the potential for ventilating from the internal space is lost by
adding insulation between the joists, retrofit vents have been specified. Measuring
100mmx200mm each, fronted with a stainless steel grill, with an internal insect
repellent mesh, they are installed 600mm from the corners of the walls, and at 2 metre
centres thereafter (Timber Queensland , 2004).
3. Dwarf Walls
The new floor joists are set on honeycombed brick dwarf walls, set a minimum of
100mm from the external walls, allowing the joists to be isolated from forming a
thermal bridge. The honeycomb pattern of the bricks allows ventilation through the
walls. Two courses of brick and a 75x100mm timber wallplate, separated by a DPC.
4. Joists & Insulation
The floor joists are skew nailed atop the wallplate and are to be 50x225 C22 timber at
400 centres as per Eurocode 5. A layer of steel mesh is moulded around the joists to
form a support for the insulation batts between, this mesh to be fixed to the external
wall behind pads of timber to support edge insulation. Between the joists, supported
by the steel mesh is fitted 225mm batts of sheep’s wool insulation, tightly packed.
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Fabric Retrofit & Refurb
30
5. Fibreboard and Floor Boards
25mm fibreboard sheathing is nailed atop the joists to prevent any draughts from
below, surviving floorboards are cleaned and re-treated, to be supplemented by new
boards from reclaimed sources where practicable.
3.2.3 Resultant U-Value
The U-value for this construction was calculated as 0.2W/m²K. While this is above
the value of 0.14W/m²K in the original Unit 01 proposal, it is well below the Part L
requirement for buildings other than dwellings of 0.25W/m²K, and I feel far more
appropriate as it does not rule out a drying function being performed on the wall from
the inner side.
Table 2: U-Value Calculation of Proposed Suspended Timber Floor
Rebuilt Suspended Ground Floor
(Through Joists - 12.5%)
Layer Thickness (m) Conductivity Resistance
Internal Surface - - 0.13
Floorboards 0.03 0.18 0.14
Fibreboard Deck 0.03 0.13 0.19
225x50 C22 Joists 0.23 0.13 1.73
External Surface - - 0.04
Total Resistance: 2.23
U-Value 0.45
(Through Joists - 87.5%)
Layer Thickness (m) Conductivity Resistance
Internal Surface - - 0.13
Floorboards 0.03 0.18 0.14
Fibreboard Deck 0.03 0.13 0.19
Sheep's Wool 0.23 0.04 5.77
External Surface - - 0.04
Total Resistance 6.27
U-Value 0.16
Total Element U-Value: 0.20
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Fabric Retrofit & Refurb
31
3.3 Existing Cut-Timber Collar Roof
3.3.1 Current Condition
The first floor of the building is more or less a half-
story, in that at present the rafters and collar
constitute the ceiling. Currently the roof is an un-
insulated cut rafter & collar construction with
sarking felt and boarding above, there is no ceiling
board so timber members are exposed internally,
leaving only the sarking and roof tiles as protection
from the elements. There is a high degree of wind
gaps through the structure and the sarking and
boarding is in bad repair. Structural surveys
undertaken prior to our own suggest the rafters and
collar joists to be in good structural condition so it is
my intention to clean, re-treat and re-use these
members as far as practicable.
The initial survey of the building and historical
research indicated the roof has been replaced since
construction, as the pitch is higher in historical
drawings. In addition, the slates are of cement fibre
and certainly not original – I have specified these be
disposed of and natural slate reinstated throughout.
In insulating the roof there was a requirement to ventilate the rafter space and above
the ceiling collar. In its current state this is impossible as the eaves overhang is
approximately 50mm with the fascia board flush against the external wall, precluding
soffit vents.
Figure 21: Existing Roof Rafters &
Collars exposed internally
Figure 20: Section of Upper Storey
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Fabric Retrofit & Refurb
32
3.3.3 Initial Unit 01 Proposal
The proposal in the Unit 01 project was minimalist – to clean and reuse the existing
slates, install batts of sheep’s wool between the joists and collar and to plasterboard
beneath – which gave a u-value of 0.25W/m²K.
3.3.3 Proposed Intervention
As with the floor, I have determined that it
is unwise to close off the loft space to
ventilation through insulating the roof,
however it would be unconscionable to
leave the joists uninsulated as more than
25% of heat loss occurs through the roof. A
possible solution to this is to retrofit more
substantial eaves. By bolting lengths of
timber to the sides of the rafter ends, I have
extended their length creating an overhang
of 200mm - while this is below the
recommended 300mm, I felt an extension of
the eaves of that size would overly change the external appearance of the building.
With the new eaves, soffit vents can be fitted.
Figure 22: 3-D showing existing eaves and roof
build-up
Figure 23: Section showing existing eaves
arrangement
Figure 24: Proposed extension of eaves to allow
soffit ventilation
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Fabric Retrofit & Refurb
33
1. Slates.
As stated, the existing fibre cement slates were disposed of, and new natural slates
installed, preferably from reclaimed sources.
2. Battens.
50x50 treated timber battens are nailed along the top of the rafters to create ventilation
space between top of ventilation and the underside of slates, atop these 50x35mm
slating battens are counter-fixed.
3. Breather membrane
This is lapped and taped between the tops of the rafters and the bottom of the battens.
4. Rafters & Insulation
The rafters and collar joists are to be cleaned and retreated after being inspected for
structural integrity. Spaces in between the joists are tension packed with 150mm
sheep’s wool.
5. Insulated Service Cavity & Ceiling
Below the rafters, 50x50 counter battens are fixed at 400 centres to allow a service
cavity and also a second layer of insulation – infilled with 50mm batts of sheep’s
wool, and finished in a 12.5mm plasterboard ceiling.
Figure 25: Section through proposed roof construction Figure 26: Section through Joists
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Fabric Retrofit & Refurb
34
3.3.4 Resultant U-Value
The U-Value calculation, performed to take account of the fractional areas of bridging,
resulted in a value of 0.2W/m² - an improvement on the Unit 01 proposal of 0.25, exactly
the requirement for Existing Buildings other than Dwellings in Part L 2008 and
substantially less than the requirement for material change of use in Part L, 35W/m2K.
(Through 50mm Insulation/150mm Insulation - 76.6%)
Layer Thickness (m) Conductivity Resistance
Internal Surface - - 0.13
Plasterboard 0.013 0.25 0.05
Sheep’s Wool 0.05 0.039 1.28
Sheep’s Wool 0.15 0.039 3.85
Fibreboard 0.025 0.13 0.19
Ventilated Cavity - - 0.34
Fibre Cement Slates 0.01 0.45 0.02
External Surface - - 0.04
Total R: 5.90
U: 0.17
(Through 50mm Insulation/ 150mm Joists - 21.8%)
Internal Surface - - 0.13
Plasterboard 0.013 0.25 0.05
Sheeps Wool 0.05 0.039 1.28
Timber Joists 0.15 0.13 1.15
Fibreboard 0.025 0.13 0.19
Ventilated Cavity - - 0.34
Fibre Cement Slates 0.01 0.45 0.02
External Surface - - 0.04
Total R: 3.21
U: 0.31
(Through 50mm Battens/ 150mm Joists - 1.6%)
Internal Surface - - 0.13
Plasterboard 0.013 0.25 0.05
Timber Battens 0.05 0.13 0.38
Timber Joists 0.15 0.13 1.15
Fibreboard 0.025 0.13 0.19
Ventilated Cavity - - 0.34
Fibre Cement Slates 0.01 0.45 0.02
External Surface - - 0.04
Total R: 2.31
U: 0.43
Total Element U-Value: 0.20
Table 3: U-Value Calculation for Proposed Roof Retrofit
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Fabric Retrofit & Refurb
35
3.4 Existing Timber Sash Windows
3.4.1 Current Condition
The existing windows are the original timber
frame single glazed sliding sashes of varying
sizes. Overall the windows appear to be in
good condition, the paintwork is heavily
degraded but there is no sign of any faults
with the actual timbers. There are a number
of panes of glass missing. A number of
windows have their original timber panelling
and architraving, most are recessed with
angled reveals, and some are flush with the
wall.
3.4.2 Initial Unit 01 Proposal
The initial proposal was to restore the
timberwork and draught proof the windows.
As this does not affect the U-Value the
laboratory tested U-Value for a traditional
timber single glazed sash window is 5.2W/m²K (Mitchell,
2008).
3.4.3 Proposed Intervention
Restoration & Draught Proofing
The deteriorated paint is to be removed and the timbers
inspected, defective areas are to be spliced with new
timbers, and the window repainted. Missing or damaged
glazing panes are to be removed and replaced where
necessary. Draught proofing is performed through
installation of draught strips and beads with incorporated
draught brushes.
Figure 28: Flush Sash Window
Figure 27: Recessed window with architrave
and panelling
Figure 29: Draughtproofing
measures for sash windows
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Fabric Retrofit & Refurb
36
Secondary Glazing
In cases of a recessed window, the fixing frame of the secondary glazing system can
be bolted into the ope wall – where the windows are more flush with the wall,
100x50mm studs on each side of the ope have been used to fix the units timber fixing
frame. Both solutions are reversible. In all cases existing timber panelling and
architraving surrounds are to be removed, cleaned and restored for reinstatement
around the secondary glazing frame.
The glazing system specified is designed to be very discreet, the entire depth of the
frame is less than 40mm and is so designed that the meeting rail is in line with that of
the existing window – rendering it concealed from outside, from inside it’s thin
profile and white finish does not provide a contrast to the existing. The optimum
distance between secondary glass and primary glass is attained, at 150mm, this
ensures optimum thermal and acoustic performance. (RMIT University, 2005)
Figure 32: Heat Camera Image showing the heat lost through
traditional sash window (right) and one with secondary glazing
(left).
Figure 31: Jamb detail: recessed window with
secondary glazing Figure 30: Jamb detail: flush window with
secondary glazing
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Fabric Retrofit & Refurb
37
3.4.4 Resultant U-Value
The table below shows the U-value attainable by performing the listed actions on the
window – A minority of the windows do have slender timber shutters, however I
determined that to insulate these would be a damaging act. As the table shows, and
independently laboratory tested (Mitchell, 2008), the resultant U-Value for traditional
sash windows with secondary glazing is 1.6W/m²K while draught proofing can
reduce air infiltration by up to 80%.
Table 4: Possible Actions for thermal upgrade of traditional
sash windows and their resultant U-Value.
Figure 33: Traditional Sash
Window with slimline discreet
aluminium framed secondary
glazing unit.
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New Construction
38
Chapter 4
New Construction
4.1 Circulation Atrium
As previously mentioned, the Unit 01
project proposal included the demolition of
the central core of the House, constructing a
new double height circulation area clad
entirely in glass to house the stairwell and
lift and to provide public access to the
house. As this is included in the thermal
efficiency comparison, this chapter deals
with the elements involved and their U-
value.
4.1.1 Atrium Structural Glass Walls & Roof
The walls and roof of the atrium are
frameless glass mounted on spider fixings
fixed to internal steel columns/beams. I
have specified a low emissivity argon-filled
glazing system. The outer pane is 6mm
glass with a low-emissivity coating,
permitting the transmission of the sun’s
short wave radiation at a higher rate than the
long wave radiation generated by the buildings heating system, also reducing glare. A
12mm argon-filled cavity separates the outer pane from the centre pane of 6mm glass,
and a further 12mm cavity separates the centre pane from the inner pane of 10mm
heat soaked toughened glass.
The manufacturers U Value rating for this arrangement is 0.8W/m2K.
Potential overheating will be mitigated by the installation of thermostat connected to
automated louvered glass vents at eaves level.
Figure 35: Triple paned structural glass
Figure 34: 3D of Atrium siting within
Cuilin House
Page 40
New Construction
39
4.1.2 Radiant Concrete Floor
The steel frame of the new atrium space is supported on a 200mm concrete slab
foundation (thickened to 450mm at edges). Atop this is 30mm sand blinding, a
DPC/Radon barrier and 150mm polyurethane board insulation. A 100mm concrete
floor deck supports the 50mm screed floor, to be finished in granite tile.
The substantial thickness of the slab and screed is to facilitate thermal storage of solar
gains and from the water-based geothermal under floor heating system.
The U-Value for this construction is 0.13W/m²K, in compliance with requirements in
Part L of the Building Regulations.
Concrete Floor @ Atrium Layer
Thickness (m) Conductivity Resistance
Internal Surface
- - 0.17
Granite Tile
0.025 2.2 0.01
Screed
0.5 0.41 1.22
Concrete
0.1 1.15 0.09
Polyurethane
0.15 0.025 6.00
Sand Blinding
0.03 0.15 0.20
External Surface
- - 0.04
7.73
Element U-Value:
0.13
Table 5: U-Value Calculation for New-Build Concrete Floor @ Atrium
Figure 36: New Build Atrium Floor
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Thermal Comparison
40
Chapter 5
Thermal Comparison
5.1 Introduction
5.1.1 General
This section aims to calculate the total heat loss from the building under the
conditions in the Unit 01 proposal project, and those demonstrated herein, contrasting
the difference in thermal efficiency between the more conservative refurbishment
proposal and this paper’s proposed thermal retrofit. Below is a table recapping the u-
values of the existing elements associated with both strategies;
Element Baseline Refurb
(Unit 01 Proposal)
Study Retrofit
(Thermal Retrofit)
External Wall 1.44 0.33
Ground Floor 0.14 0.2
Roof 0.25 0.2
Windows 5.2 1.6
First Floor (Joists packed
with Sheep’s Wool) 0.2 0.2
Internal Walls (Solid Brick,
12.5 plasterboard) 1.46 1.46
Table 6: Summary of Element U-Values.
5.1.2 Heat Losses Generally
Total heat loss for a building is derived from total transmission or fabric losses added
to ventilation and infiltration losses for each space in the building. These values
determine the sizing of the heating appliance in each room, and thus the overall
energy load required to heat the building. There are a number of methods used to
calculate this loss used by engineers, The Chartered Institution of Building Services
Engineers (CIBSE) in the UK use a number of increasingly complex methodologies
as a project progresses from outline through design to implementation stage:
• Concept Stage: Rules of Thumb methods
• Design Stage: Steady State Calculation
• Final Design: Dynamic Transient Method
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Thermal Comparison
41
The approach taken in this paper is the Steady State method, whereby transmission
and ventilation losses are calculated with a pre-determined design external
temperature, design internal temperature, design air change rate.
5.1.3 Steady State Heat Loss Calculation
In this method, also known as the manual-method, calculation of transmission heat
losses is arrived at by multiplying the element area of a particular building element
within the space, by its u-value, by the design temperature difference, repeating for all
fabric elements in the space being evaluated. Transmission of heat from one internal
space to another where there is a design temperature difference is included, but
naturally this balances itself out as the transmission heat loss from one is a
transmission heat gain in the other.
Calculating ventilation heat loss is performed by multiplying the space volume by the
design temperature difference, by the design air changes per hour, by the specific heat
capacity of air. In a traditional building the target air changes per hour after draught-
proofing measures are undertaken is 0.8ac/h (English Heritage, 2010) – I have used
this value for this study’s retrofit, and a higher rate of 1ac/h for the shallow retrofit to
reflect a less intensive upgrade.
The variables used in the calculation are as follows:
Internal Design Temperature: The temperature level recommended by engineering
and plumbing industry bodies to maintain comfort, determined by the purpose of the
space (e.g. Internal design temperature for a small office = 20˚C).
External Design Temperature: Based on the location of the building, the external
design temperature or heating dry-bulb temperature is not the lowest temperature
expected, but rather “close to lowest”. The following calculations use the 99% design
temperature for Dublin, Ireland tabulated by ASHRAE (American Society of Heating,
Refrigeration and Air-Conditioning Engineers), which means a low temperature that
will be exceeded, statistically speaking, for 88 hours in a typical year.
Design Temperature Difference: Or delta-t is the difference in temperature between
the internal design temperature and the external design temperature.
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Thermal Comparison
42
U-Value: a measure of the heat transmission through a building part such as a wall or
roof, with a varied build-up of materials and levels of conductivity, with lower
numbers indicating better insulating properties.
Element Area: Tabulated by measuring the area of external wall or roof within the
space being calculated – taken from the internal dimensions.
Space Volume: The internal volume of the room, from internal dimensions.
Air Changes / per Hour: A measure of how many times the air within a space is
replaced due to ventilation and infiltration – a design value is applied, taking into
account desired and recommended ventilation levels and the control of infiltration
through new wall linings and draught seals.
Specific Heat Capacity: In this case, of air, it is the measurable physical quantity that
characterizes the amount of heat required to raise air temperature by a given amount.
For heating calculations the value of 0.33 is always applied.
Total Transmission Heat Loss: The total heat that is lost from internal spaces
through the fabric of the building in Watts per Hour
Total Ventilation Heat Loss: The total heat that is lost from the internal spaces
through ventilation and infiltration in Watts per Hour
Total Design Heat Loss: The sum of transmission and ventilation heat losses, that
occur over a steady state.
Assumptions used in Design Heat Loss Calculation:
• Assumed to occur at night, where no solar loads act on building
• Building is treated as unoccupied (no internal loads)
• Equipment and appliances are not in operation.
• Lights are off
• Moisture loads ignored
• Heat flow is analysed using static conditions, meaning stable temperatures
over the defined period of time (one hour)
• Heat storage in the fabric is discounted.
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Thermal Comparison
43
The following is a summary of the inputs required to calculate:
Design Temperatures
Internal (Watkins, 2011):
Space Type Temp
Office 20˚C
Storage 18˚C
Circulation 16˚C
Exhibition 18˚C
Plant 15˚C
Entrance Hall 15˚C
External (ASHRAE, 1981)
Heating Dry Bulb Temperature for Dublin, Ireland: -1˚C
Table 7: Design Internal & External Temperatures
Figure 38: Ground Floor Plan with internal
and external design temperatures.
Figure 37: First Floor Plan with internal
and external design temperatures.
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Thermal Comparison
44
5.2 Total Transmission Heat Loss
Full calculation tables are provided in Appendix B, an example calculation is
demonstrated below:
U-Value x Area of Element x Temperature Difference = Heat Loss through that element
Example:
Component UValue(W/m2) Element Δ
(m2)
Temp. Diff.
(Int-Ext)
Heat Loss
(W/hr)
External Wall 0.33 32.30 21.00 223.84
Table 8: Example Heat Loss Calculation for external wall in one room.
The resulting heat loss is given in Watts per Hour under the design conditions
mentioned previously. Repeated for each element (e.g. external wall, floor, roof) in
each space and added together, the result is the total heat loss under steady state
analysis experienced by the building. The following table is a summary of results in
both the Unit 01 refurb proposal, and the thermal retrofit proposal herein, by space
and in total.
Unit 01 Proposal:
Space
Heat Loss
(W/hr)
1 Conference Room 1808.83
2 Reception 546.94
3 Entrance Hall -13.63
4 Office1 1528.36
5 Office 2 846.08
6 Plant 468.34
7 Exhibition Space 2012.84
8 Exhib. Reception 580.20
9 Lobby 110.38
10 Office 3 1363.67
11 Office 4 755.44
12 Glazed Atrium 2566.32
Total Transmission Heat Loss 12573.78
Table 9: Transmission Heat Loss by Space – Unit 01
The result of the calculation was a total transmission heat loss of 12,500 watts per
hour, or 12.5 Kilowatts per hour (KW/hr).
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Thermal Comparison
45
Thermal Retrofit:
Space
Heat Loss
(W/hr)
1 Conference Room 667.50
2 Reception 246.42
3 Entrance Hall -9.78
4 Office1 530.81
5 Office 2 262.76
6 Plant 92.17
7 Exhibition Space 664.62
8 Exhib. Reception 263.01
9 Lobby -54.16
10 Office 3 474.36
11 Office 4 233.86
12 Glazed Atrium 2566.32
Total Transmission Heat Loss 5937.89
Table 10: Transmission Heat Losses by Space – Deep Retrofit
The result of the calculation was a total transmission heatloss of 6,000 watts per hour,
or 6 Kilowatts per hour (KW/hr) : A 53% improvement on the Unit 01 Proposal
Page 47
Thermal Comparison
46
5.3 Total Ventilation Heat Loss
As stated in 3.1.3, the only different variable in the ventilation heat loss calculation
for both retrofit models is the air change rate – full calculations of ventilation heat
loss are set out below:
Unit 01 Proposal:
Space Vol (m3)
Delta
T AC/H Sp. Ht. Cap. Total (W)
1.Conference 120 21 1 0.33 831.60
2. Reception 44.63 21 1 0.33 309.29
3. Entrance 22.3 17 1 0.33 125.10
4. Office 1 60.2 21 1 0.33 417.19
5. Office 2 41.8 21 1 0.33 289.67
6. Plant 58.2 16 1 0.33 307.30
Ground Floor: 2280.14 Watts
7. Exhibition 159.57 19 1 0.33 1000.50
8. Ex. Reception 38.78 21 1 0.33 268.75
9. Lobby 19.4 17 1 0.33 108.83
10. Office 3 52.4 21 1 0.33 363.13
11. Office 4 36.87 21 1 0.33 255.51
First Floor: 1996.72 Watts
12. Atrium 384 17 1 0.33 2154.24
Ventilation Losses: 6431.11 Watts
Table 11: Calculation Table of Ventilation Heat Losses – Shallow Retrofit
Thermal Retrofit:
Table 12: Calculation Table of Ventilation Heat Losses – Deep Retrofit
Space Vol (m3) Delta T AC/H Sp. Ht. Cap. Total (W)
1.Conference 120 21 0.8 0.33 665.28
2. Reception 44.63 21 0.8 0.33 247.43
3. Entrance 22.3 17 0.8 0.33 100.08
4. Office 1 60.2 21 0.8 0.33 333.75
5. Office 2 41.8 21 0.8 0.33 231.74
6. Plant 58.2 16 0.8 0.33 245.84
Ground Floor: 1824.12 Watts
7. Exhibition 159.57 19 0.8 0.33 800.40
8. Ex. Reception 38.78 21 0.8 0.33 215.00
9. Lobby 19.4 17 0.8 0.33 87.07
10. Office 3 52.4 21 0.8 0.33 290.51
11. Office 4 36.87 21 0.8 0.33 204.41
First Floor: 1597.38 Watts
12. Atrium 384 17 0.8 0.33 1723.39
Infiltration Losses: 5144.89 Watts
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Thermal Comparison
47
The Unit 01 entails a ventilation heat loss / load of 6400 watts per hour, or 6.4
Kilowatts per hour (KW/hr), where the thermal retrofit carries a loss of 5100 watts per
hour or 5.1KW/hr, or a 20% improvement on the Unit 01 proposal.
5.4 Total Heat Loss & Demand
Total heat loss is the sum of transmission and ventilation heat loss:
Deep Retrofit Shallow Retrofit Transmission Losses 5937.89W/hr 13085.31W/hr
Ventilation Losses 5144.89W/hr 6431.11W/hr
Total (W/hr) 11082 W/hr 19516W/hr
Total (KW/hr) 11.1 KW/hr 19.5 KW/hr
Table 13: Total Heat Losses
Overall, the thermal retrofit outlined in this paper constitutes a 43 percent
improvement in thermal efficiency on the original Unit 01 thesis proposal, without
compromising the natural balance traditional constructions exist in.
Page 49
Conclusion
48
Chapter 6
Conclusion
To recap, this dissertation set out to explore and analyse the considerations involved
in thermally retrofitting an historic building, while balancing the considerations
around conservation principles and the requirements of traditional constructions.
The paper has set out a strategy that aims to do the least harm, if not aid the building
fabric in its moisture regulation and thermal functions. Using best practice
recommendations and guidance from prime actors in the area of conservation and
thermal comfort, it has sought to apply the principles learned to the existing fabric of
Cuilín House.
The attaching of u-values to the hypothesised construction, and the comparison to the
base line model through use of the Steady State Heat Loss Method have demonstrated
that the proposal achieved a 53% thermal efficiency increase, while interventions to
the floors, (such as the addition of a trench drain and subfloor ventilation), and walls,
(such as the hygroscopically active insulation) could actually benefit their moisture
control function. Further, conservation principles were satisfied – in that with all but
the replacement suspended floor, every intervention is reversible –and by the retention
of what limited window architraving, moulding and panelling remained, the internal
character has been somewhat restored.
I believe this is a sensitive, non-obtrusive retrofit strategy, it preserves the character of
the traditional windows and the traditional materials throughout, while significantly
improving the prospects for thermal comfort, and thus those of the continued survival
of the building as a used space – the ultimate goal in conservation.
In conclusion, from the perspective of modern architectural technology, where there is
a lot of emphasis on moisture eradication and airtightness, dealing with older walls
requires a shift in thinking, to one of control and regulation of moisture and allowing
the building to breath as it has always done – what seems simple and old often has
hidden qualities and controls.
Page 50
References
49
References / Bibliography
Bibliography ASHRAE. (1981). Design Conditions for Selected Locations. In ASHRAE Handbook
(p. Appendix ). Atlanta: American Society of Heating, Refrigerating and Air-
Conditioning Engineers.
Cambridge Architectural Research. (2009). Breathability – A White Paper.
Cambridge: Kingspan Insulation Ltd. .
Cambridge University. (2005). Potential for Microgeneration - Study and Analysis.
Cambridge: The Energy Saving Trust.
Curtis, R. (2008). Energy Efficiency in Traditional Homes. Edinburgh: Historic
Scotland.
Department of Environment, Heritage and Local Government. (1996). Conservation
Guidelines - Windows. Dublin: Government of Ireland.
Department of the Environment, Heritage & Local Government. (2010). Energy
Efficiency in Traditional Buildings. Dublin: Government of Ireland.
Eco Warriors Solar (UK) Ltd. . (2010). How it works: Solar Photovoltaics For Your
Home. Retrieved April 18, 2012, from E-W-Solar: http://www.e-w-
solar.com/solarPvHowItWorks.shtml
Energy Saving Trust. (2006). Practical Refurbishment of Solid-Walled Houses.
London: Energy Saving Trust.
English Heritage . (1997). Framing Opinions 5: Timber Sash Windows. Swindon:
English Heritage.
English Heritage. (1994). Framing Opinions 1: Draught Proofing and Secondary
Glazing . Swindon: English Heritage.
English Heritage. (2010). Energy Efficiency in Historic Buildings - Draught Proofing
Windows and Doors. London: English Heritage.
English Heritage. (2010). Energy Efficiency in Historic Buildings - Insulating solid
walls. London: English Heritage.
Historic Scotland. (2008). Sash & Case Windows: A Short Guide for Homeowners.
Edinburgh: Historic Scotland.
Page 51
References
50
Irish Eco Homes. (2010). Sheeps Wool. Retrieved March 27, 2012, from Irish Eco
Homes: http://www.irishecohomes.ie/
May, N. (2005). Breathability: the Key to Building Performance. London: Natural
Building Co.
May, N. (2009). Breathability Matters: Why the Kingspan White Paper is seriously
misleading . London: Natural Building Co.
Mitchell, D. S. (2008). Energy Efficiency in Traditional Homes. Edinburgh: Historic
Scotland .
Morgan, C. (2008). Breathing Buildings. Dunblane: SelfBuild.ie - Extend & Renovate
Ireland.
Northern Ireland Environment Agency. (2010). Windows: A Guidance Booklet on
Openings . Belfast: Northern Ireland Environment Agency.
RMIT University. (2005). Sound Insulation for Windows. Melbourne: City of
Melbourne.
Society for the Protection of Ancient Buildings. (2009). Technical Q&A 19 : French
Drains. Retrieved April 9, 2012, from SPAB:
http://www.spab.org.uk/advice/technical-qas/technical-qa-19-french-drains/
Society for the Protection of Ancient Buildings. (2009). The Need for Old Buildings
to ‘Breathe’. London: SPAB.
Timber Queensland . (2004). Technical Data Sheet 14 - Sub-floor Ventilation.
Brisbane: Timber Queensland.
Watkins, D. E. (2011). Heating Services in Buildings. Chichester: John Wiley & Sons
Ltd. .
Page 52
Appendix
51
Appendix A – U Value Calculations
Notes on U-Value Calculations In calculating the U-Value of the external wall
there are a level of unknowns around the
composition of the existing solid wall. The
presence of voids / a rubble core is not accounted
for and thus the result may be more valuable in a
comparison of the effect of internal insulation
compared to leaving the existing in place
The external wall insulation layer is composed of
battens and counter battens with the wool packed
between, thus U-values were taken through the
batten-on-batten route, the batten on insulation
and insulation on insulation layers and the values
added according to their distribution throughout the wall. Similarly the roof is treated
the same where battens run perpendicular along the underside of the joists.
Figure 39: Fractional Areas of materials
in the cross-battened wall/roof
Page 53
Appendix
52
Unit 01 External Wall Proposal
Through 50mm Batten/50mm Insulation (21.8%)
Layer Thickness (m) Conductivity Resistance
Internal Surface - - 0.13
Plaster 0.018 0.8 0.02
Clay Brick 0.21 0.77 0.27
Limestone 0.29 1.26 0.23
External Surface - - 0.04
0.70
Total Element U-Value: 1.44
Rebuilt Suspended Ground
Floor
(Through Joists - 12.5%)
Layer Thickness (m) Conductivity Resistance
Internal Surface - - 0.13
Floorboards 0.03 0.18 0.14
Fibreboard Deck 0.03 0.13 0.19
225x50 C22 Joists 0.23 0.13 1.73
External Surface - - 0.04
Total Resistance: 2.23
U-Value 0.45
(Through Joists - 87.5%)
Layer Thickness (m) Conductivity Resistance
Internal Surface - - 0.13
Floorboards 0.03 0.18 0.14
Fibreboard Deck 0.03 0.13 0.19
Sheep's Wool 0.23 0.04 5.77
External Surface - - 0.04
Total Resistance 6.27
U-Value 0.16
Total Element U-Value: 0.20
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Appendix
53
Thermal Retrofit of External Wall
(Through 50mm Batten/50mm Insulation - 21.8%)
Layer Thickness (m) Conductivity Resistance
Internal Surface - - 0.13
Plasterboard 0.015 0.25 0.06
Sheeps Wool 0.05 0.039 1.28
Timber Battens 0.05 0.13 0.38
Lime Plaster 0.018 0.43 0.04
Clay Brick 0.21 0.77 0.27
Limestone 0.29 1.26 0.23
External Surface - - 0.04
Total R: 2.44
U-Value: 0.41
(Through 100mm Battens/Battens - 1.6%)
Layer Thickness (m) Conductivity Resistance
Internal Surface - - 0.13
Plasterboard 0.015 0.25 0.06
Timber Battens 0.05 0.13 0.38
Timber Battens 0.05 0.13 0.38
Lime Plaster 0.018 0.43 0.04
Clay Brick 0.21 0.77 0.27
Limestone 0.29 1.26 0.23
External Surface - - 0.04
Total R: 1.54
U-Value: 0.65
(Through 100mm Wool Batts/Wool Batts - 76.6%)
Layer Thickness (m) Conductivity Resistance
Internal Surface - - 0.13
Plasterboard 0.015 0.25 0.06
Sheeps Wool 0.05 0.039 1.28
Sheeps Wool 0.05 0.039 1.28
Lime Plaster 0.018 0.43 0.04
Clay Brick 0.21 0.77 0.27
Limestone 0.29 1.26 0.23
External Surface - - 0.04
Total R: 3.34
U-Value: 0.30
Total Element U-Value: 0.33
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Appendix
54
Unit 01 Proposed Roof
Refurb
(Through Insulation - 87.5%)
Layer Thickness (m) Conductivity Resistance
Internal Surface - - 0.13
Plasterboard 0.013 0.25 0.05
Sheeps Wool 0.15 0.039 3.85
Fibreboard 0.025 0.13 0.19
Ventilated Cavity - - 0.34
Fibre Cement Slates 0.01 0.45 0.02
External Surface - - 0.04
4.62
0.22
(Through Rafters - 12.5%)
Layer Thickness (m) Conductivity Resistance
Internal Surface - - 0.13
Plasterboard 0.013 0.25 0.05
Timber Rafters 0.15 0.13 1.15
Fibreboard 0.025 0.13 0.19
Ventilated Cavity - - 0.34
Fibre Cement Slates 0.01 0.45 0.02
External Surface - - 0.04
1.93
0.52
Total Element U-Value: 0.25
Page 56
Appendix
55
Retrofitted Cut Timber Roof
(Through 50mm Insulation/150mm Insulation - 76.6%)
Layer Thickness (m) Conductivity Resistance
Internal Surface - - 0.13
Plasterboard 0.013 0.25 0.05
Sheeps Wool 0.05 0.039 1.28
Sheeps Wool 0.15 0.039 3.85
Fibreboard 0.025 0.13 0.19
Ventilated Cavity - - 0.34
Fibre Cement Slates 0.01 0.45 0.02
External Surface - - 0.04
5.90
0.17
(Through 50mm Insulation/ 150mm Joists - 21.8%)
Layer Thickness (m) Conductivity Resistance
Internal Surface - - 0.13
Plasterboard 0.013 0.25 0.05
Sheeps Wool 0.05 0.039 1.28
Timber Joists 0.15 0.13 1.15
Fibreboard 0.025 0.13 0.19
Ventilated Cavity - - 0.34
Fibre Cement Slates 0.01 0.45 0.02
External Surface - - 0.04
3.21
0.31
(Through 50mm Battens/ 150mm Joists - 1.6%)
Layer Thickness (m) Conductivity Resistance
Internal Surface - - 0.13
Plasterboard 0.013 0.25 0.05
Timber Battens 0.05 0.13 0.38
Timber Joists 0.15 0.13 1.15
Fibreboard 0.025 0.13 0.19
Ventilated Cavity - - 0.34
Fibre Cement Slates 0.01 0.45 0.02
External Surface - - 0.04
2.31
0.43
Total Element U-Value: 0.20
Page 57
Appendix
56
Internal Wall Type 1 (450 Solid Brickwork)
Layer Thickness (m) Conductivity Resistance
Plasterboard 0.013 0.25 0.05
Clay Brick 0.450 0.77 0.58
Plasterboard 0.013 0.25 0.05
0.68
Total Element U-Value: 1.46
Page 58
Appendix
57
Appendix B – BuildDesk Condensation Analyses
As discussed in 3.1.2, I ran a number of demonstration simulations on refurbishing the
external wall with a synthetic non-breathable insulant to highlight how inappropriate
modern construction theory would be if applied to the walls.
Firstly, determining that a thickness of 50mm insulation would be a good starting
point, I ran an analysis using a solid wall of Limestone at 490mm thickness,
polyurethane board mechanically fixed to the inner face with a dabbed plasterboard
finish internally for a U-Value of 0.55W/m²K, results as follows:
Page 59
Appendix
58
Reducing the thickness of the polyurethane by 10mm increments, at 20mm thickness
the wall was deemed to have passed the test, in that condensation occurs during the
summer months but was expected to fully evaporate, only giving a U-Value of
0.79W/m²K:
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Appendix
59
Adding a foil backing to the plaster board (i.e. on the warm side of the insulation)
ruled out the risk of interstitial condensation at any time with thicknesses up to
100mm and beyond and giving a U-Value of 0.42W/m²K using 50mm polyurethane
board layer:
My contention is that, aside from this tool not taking into account any bridging and
assuming all homogenous layers, the success or failure of the use of synthetic
insulants is wholly determined by the integrity of the vapour barrier or foil layer, and
as it is common for these membranes to be punctured either during construction or
later by occupants nailing through the plasterboard, it is wholly inappropriate to
specify a vapour-barrier based system to the external walls in this case.
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Appendix
60
Appendix C – Fabric Heat Loss Calculations
Unit 01 Refurb - Fabric Heat Load :
1. Conference
Component U-Value(W/m2K Element Δ (m2) Temp. Diff.
Heat Loss
(W/hr)
External Wall 1.46 32.30 21.00 990.32
Windows 5.20 5.70 21.00 622.44
Internal Walls 1.46 13.20 2.00 38.54
Floor 0.14 44.50 21.00 130.83
Ceiling 0.20 44.50 3.00 26.70
Fabric Heat
Loss 1808.83 W
2. Reception
Component U-Value Element Δ (m2) Temp. Diff.
Heat Loss
(W/hr)
External Wall 1.46 9.08 21.00 278.39
Windows 5.20 1.40 21.00 152.88
Internal Wall 1.46 11.50 4.00 67.16
Floor 0.14 16.50 21.00 48.51
Fabric Heat
Loss 546.94 W
3. Entrance
Component U-Value Element Δ (m2) Temp. Diff.
Heat Loss
(W/hr)
External Wall 1.46 5.20 17.00 129.06
Floor 0.14 8.26 17.00 19.66
Internal Walls 1.46 27.80 -4.00 -162.35
Fabric Heat
Loss -13.63 W
4. Office 1
Component U-Value Element Δ (m2) Temp. Diff.
Heat Loss
(W/hr)
External Wall 1.46 23.82 21.00 730.32
Internal Wall 1.46 11.55 4.00 67.45
Floor 0.14 22.30 21.00 65.56
Windows 5.20 6.09 21.00 665.03
Fabric Heat
Loss 1528.36 W
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Appendix
61
5. Office 2
Component U-Value Element Δ (m2) Temp. Diff.
Heat Loss
(W/hr)
External Wall 1.46 19.68 21.00 603.39
Floor 0.14 15.69 21.00 46.13
Window 5.20 1.80 21.00 196.56
Fabric Heat
Loss 846.08 W
6. Plant
Component U-Value Element Δ (m2) Temp. Diff.
Heat Loss
(W/hr)
External Wall 1.46 17.49 16.00 408.57
Internal Wall 1.46 13.20 -5.00 -96.36
Windows 5.20 1.40 16.00 116.48
Floor 0.14 21.55 16.00 48.27
Ceiling 0.20 21.55 -2.00 -8.62
Fabric Heat
Loss 468.34 W
7. Exhibit Space
Component U-Value Element Δ (m2) Temp. Diff.
Heat Loss
(W/hr)
External Wall 1.46 39.20 19.00 1087.41
Windows 5.20 6.38 19.00 630.34
Floor 0.20 67.80 -2.00 -27.12
Roof 0.25 73.90 19.00 351.03
Internal Wall 1.46 9.87 -2.00 -28.82
Fabric Heat
Loss 2012.84 W
8. Exhib. Reception
Component U-Value Element Δ (m2) Temp. Diff.
Heat Loss
(W/hr)
External Wall 1.46 8.90 21.00 272.87
Internal Wall 1.46 9.87 2.00 28.82
1.46 9.87 4.00 57.64
Roof 0.25 18.15 21.00 95.29
Window 5.20 1.15 21.00 125.58
Fabric Heat
Loss 580.20 W
9. Lobby
Component U-Value Element Δ (m2) Temp. Diff.
Heat Loss
(W/hr)
External Wall 1.46 4.50 17.00 111.69
Internal Wall 1.46 24.24 -4.00 -141.56
Roof 0.25 9.08 17.00 38.59
Window 5.20 1.15 17.00 101.66
Fabric Heat 110.38 W
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Appendix
62
Loss
10. Office 3
Component U-Value Element Δ (m2) Temp. Diff.
Heat Loss
(W/hr)
External Wall 1.46 21.29 21.00 652.75
Internal Wall 1.46 11.05 4.00 64.53
Roof 0.25 24.53 21.00 128.78
Window 5.20 4.74 21.00 517.61
Fabric Heat
Loss 1363.67 W
11. Office 4
Component U-Value Element Δ (m2) Temp. Diff.
Heat Loss
(W/hr)
External Wall 1.46 17.54 21.00 537.78
Roof 0.25 17.54 21.00 92.09
Window 5.20 1.15 21.00 125.58
Fabric Heat
Loss 755.44 W
12. Atrium
Component U-Value Element Δ (m2) Temp. Diff.
Heat Loss
(W/hr)
Glazed Wall 0.80 114.30 17.00 1554.48
Glazed Roof 0.80 64.00 17.00 870.40
Concrete Floor 0.13 64.00 17.00 141.44
Fabric Heat
Loss 2566.32 W
TOTAL TRANSMISSION
LOSS: 12573.78 W/hr
Page 64
Appendix
63
Dissertation Thermal Retrofit
1. Conference
Component
U-
Value(W/m2K
Element Δ
(m2) Temp. Diff.
Heat Loss
(W/hr)
External Wall 0.33 32.30 21.00 223.84
Windows 1.60 5.70 21.00 191.52
Internal Walls 1.46 13.20 2.00 38.54
Floor 0.20 44.50 21.00 186.90
Ceiling 0.20 44.50 3.00 26.70
Fabric Heat Loss 667.50 W
2. Reception
Component U-Value
Element Δ
(m2) Temp. Diff.
Heat Loss
(W/hr)
External Wall 0.33 9.08 21.00 62.92
Windows 1.60 1.40 21.00 47.04
Internal Wall 1.46 11.50 4.00 67.16
Floor 0.20 16.50 21.00 69.30
Fabric Heat Loss 246.42 W
3. Entrance
Component U-Value
Element Δ
(m2) Temp. Diff.
Heat Loss
(W/hr)
External Wall 0.33 3.10 17.00 17.39
Door 3.00 2.10 17.00 107.10
Floor 0.20 8.26 17.00 28.08
Internal Walls 1.46 27.80 -4.00 -162.35
Fabric Heat Loss -9.78 W
4. Office 1
Component U-Value
Element Δ
(m2) Temp. Diff.
Heat Loss
(W/hr)
External Wall 0.33 23.82 21.00 165.07
Internal Wall 1.46 11.55 4.00 67.45
Floor 0.20 22.30 21.00 93.66
Windows 1.60 6.09 21.00 204.62
Fabric Heat Loss 530.81 W
5. Office 2
Component U-Value
Element Δ
(m2) Temp. Diff.
Heat Loss
(W/hr)
External Wall 0.33 19.68 21.00 136.38
Floor 0.20 15.69 21.00 65.90
Window 1.60 1.80 21.00 60.48
Fabric Heat Loss 262.76 W
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Appendix
64
6. Plant
Component U-Value
Element Δ
(m2) Temp. Diff.
Heat Loss
(W/hr)
External Wall 0.33 17.49 16.00 92.35
Internal Wall 1.46 13.20 -5.00 -96.36
Windows 1.60 1.40 16.00 35.84
Floor 0.20 21.55 16.00 68.96
Ceiling 0.20 21.55 -2.00 -8.62
Fabric Heat Loss 92.17 W
7. Exhibit Space
Component U-Value
Element Δ
(m2) Temp. Diff.
Heat Loss
(W/hr)
External Wall 0.33 39.20 19.00 245.78
Windows 1.60 6.38 19.00 193.95
Floor 0.20 67.80 -2.00 -27.12
Roof 0.20 73.90 19.00 280.82
Internal Wall 1.46 9.87 -2.00 -28.82
Fabric Heat Loss 664.62 W
8. Exhib.
Reception
Component U-Value
Element Δ
(m2) Temp. Diff.
Heat Loss
(W/hr)
External Wall 0.33 8.90 21.00 61.68
Internal Wall 1.46 9.87 2.00 28.82
1.46 9.87 4.00 57.64
Roof 0.20 18.15 21.00 76.23
Window 1.60 1.15 21.00 38.64
Fabric Heat Loss 263.01 W
9. Lobby
Component U-Value
Element Δ
(m2) Temp. Diff.
Heat Loss
(W/hr)
External Wall 0.33 4.50 17.00 25.25
Internal Wall 1.46 24.24 -4.00 -141.56
Roof 0.20 9.08 17.00 30.87
Window 1.60 1.15 17.00 31.28
Fabric Heat Loss -54.16 W
10. Office 3
Component U-Value
Element Δ
(m2) Temp. Diff.
Heat Loss
(W/hr)
External Wall 0.33 21.29 21.00 147.54
Internal Wall 1.46 11.05 4.00 64.53
Roof 0.20 24.53 21.00 103.03
Window 1.60 4.74 21.00 159.26
Fabric Heat Loss 474.36 W
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Appendix
65
11. Office 4
Component U-Value
Element Δ
(m2) Temp. Diff.
Heat Loss
(W/hr)
External Wall 0.33 17.54 21.00 121.55
Roof 0.20 17.54 21.00 73.67
Window 1.60 1.15 21.00 38.64
Fabric Heat Loss 233.86 W
12. Atrium
Component U-Value
Element Δ
(m2) Temp. Diff.
Heat Loss
(W/hr)
Glazed Wall 0.80 114.30 17.00 1554.48
Glazed Roof 0.80 64.00 17.00 870.40
Concrete Floor 0.13 64.00 17.00 141.44
Fabric Heat Loss 2566.32 W
TOTAL TRANSMISSION LOSS: 5937.89 W/hr
Page 67
Appendix
66
Appendix D – Overall Unit 01 Proposal To place the works proposed herein into context, the following are drawings from the
Unit01 proposal for the overal redevelopment of Cuilín House.