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1. Introduction

Today’s global scenario is portending drastic climatic changes and higher emissions of greenhouse

gases in the near future. The United Kingdom alone is predicted to face extreme weather transformations

and natural calamities such as flooding, heat waves and rainfall1. It is possible to tackle the issues related

to climate change and carbon emissions on new buildings by sustainable planning. The issues arise in case

of existing buildings, which comprise of 70% of the building stock in UK2 and ancient buildings which

face a challenge of coping with the present and future climatic changes, since they were designed to suit

the ancient conditions in which they were built. Buildings in the United Kingdom contribute to 44-48% of

the country’s carbon emissions3 and ancient buildings in particular have greater emissions, due to the age

of their fabric. However, UK is committed to reduce its CO2 emissions by 80% in 20504. The English

Heritage in collaboration with, commissioned University College London (Centre for Sustainable

Heritage) is investigating the scope, risks and suitable strategies of mitigation and adaptation of the

heritage buildings in the UK to the future climatic change5.

In the UK, an additional 1.5% is added to the existing building stock each year and, in 2010,

approximately 3,72,000 were listed buildings entries6. But the issues of sustainability related to ancient

and existing buildings largely remains unsolved. As buildings of historical significance are very valuable,

much effort must be made to retain its character and make it fit to pass on to the future generations.

1,3 Jones, L., Elridge, Adam et al. 2008.Retrofitting Soho: improving the sustainability of historic core areas, University of Westminster, London. pp 12

4The UK Low Carbon Transition Plan, 2009, pp 6, pp 99

2 Hay, Hergen. 2009. Presentation at Ecobuild London

5 Cassar, May. 2005. Centre for Sustainable Heritage, University College London.

6English Heritage. 2010. English Heritage Website. Available from http://www.english-heritage.org.uk/. Accessed on 20.05.2012.

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2. Preservation Philosophies

Early philosophies of preservation began as a cosmetic revival of the buildings to salvage a dying

style of design, with the onset of a newer style. In France particularly, monuments were dominated by a

medieval civilisation and architects and artists worked at ‘de’restoring them by omitting nonconforming

additions, regardless of their beauty or significance1. With the onset of doctrines of Viollet- Le- Duc of

stylistic restoration, which claimed that restored buildings must be re-established to such a finished state

which does not place it in anytime2. Although, this contradicts the sustainable theory of confirming

buildings to the local context, it geared the philosophies of maintaining historical value of buildings.

Jane Jacobs stressed on the importance of historic preservation to ensure the longevity of a city. In

her book The Death and Life of Great American Cities, 1961, she pointed out that old buildings are an

important portion of a city’s infrastructure that growth of its streets and districts is inevitable without

them3. Hence the patina of historic buildings being evidences the evolution of the city through time.

The polemics of Cullen (1961) and Lynch (1964) revolved around the contribution of buildings to

townscapes in UK, by reflecting on the reaction of the general public to the demolition of old buildings

and their replacement by modern structures 4,5. Hence under the Civic Amenities Act of 1967, this

reactionary approach resulted in formation of conservation areas in Britain and gave rise to a kind of

‘facadism’ where new buildings were concealed under the old skins. However, this superficial approach

was unsuccessful in contributing to the genius loci of the place6. Hence it is necessary to preserve the

character of a building to denounce the significance of its time.

1 Semes, S.W. 2009. The future of the past : a conservation ethic for architecture, urbanism, and historic preservation. W.W. Norton, London

2 Viollet-le-Duc. 1990. The foundations of Architecture: Selections from the Dictionnaire Raisonne. New York: Braziller. pp195

3 Jacobs, Jane. 1961. The Death and Life of Great American Cities. Cape, London

4 Cullen, G. 1961. Townscape. Architectural Press, London.

5 Lynch, K. 1964. The Image of the City. MIT Press/Harvard University Press, Cambridge, MA.

6 Wood, B.2006. The role of existing buildings in the sustainability agenda. Facilities, Vol. 24 Issue: 1 pp. 61 - 67

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3. Sustainable Philosophies

The most common definition of Sustainability is “A development that meets the needs of the

present without compromising the ability of future generations to meet their own needs”1. Sustainability

comprises of three aspects- environmental, economic and social aspects and a balance is required between

the three. For historic buildings in the United Kingdom, a perturbing issue is their Carbon Dioxide (CO2)

emissions, which is a key problem in the environmental aspect of sustainability. These issues influence a

wider agenda which has major political, economic and social implications2. Hence, to improve the overall

environment greenhouse gas emission, the existing building stock must be improved3.

The term sustainability has various interpretations. Here, the definition of sustainability is:

Architecture that causes minimum environmental impact and ensures longevity. ‘Architecture’ here means

any interventions applied on any historically significant building. ‘Minimum Environmental Impact’

means a less strenuous approach of preservation on the environment that may be reversible. ‘Longevity’

implies prolonging the value of buildings through the future without compromising on its historical

significance.

4. Sustainable evaluation of ancient buildings

A twofold approach of preserving the historical content of heritage buildings as well as making

them environmentally viable can be achieved by reusing, retrofitting or refurbishing them. Ancient

buildings consume a valuable portion of an urban environment but also consume energy and contribute to

green house gas emission. For example, existing buildings consume 40% of energy in the United States of

America and 68% of electricity 4.

1 Brundtland Commission. 1987. Available on http://en.wikipedia.org/wiki/Brundtland_Commission. Accessed on 20.05.2012

2 Godwin, P.J. 2011. Building Conservation and Sustainability in the United Kingdom. Science Direct, Volume 20, pp12-21

3 Wilkinson, J.S., Reed, R.J.2006. Office buildings and the environment – the increasing importance of ESD. 12th Annual Pacific Rim Real Estate Conference, University of Auckland, New Zealand. Available on http://www.prres.net/papers/Wilkinson_Office_buildings_and_the_environment.pdf. Accessed on 19.05.2012

4 National Trust for Historic Preservation. 2012. Available on http://www.preservationnation.org/information-center/sustainable-communities/sustainability/green-lab/. Accessed on 17.05.2012.

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A feasible solution to overcome this issue is by encouraging retrofitting of existing buildings.

Apart from the quantitative advantages of retrofitting an existing building, such as increased job creations,

there are also qualitative benefits such as reinforcing a sense of place and community preservation1.

5. Sustainable issues related to Conservation

The issues of sustainability that relate to historically significant buildings will be discussed with

the help of case studies, in terms of the following points:

5.1 Sustainable use of Resources

Ancient buildings are constantly under the threat of deterioration and are often faced with two

divergent verdicts- demolition or salvaging them. During demolition of a building, all of the resources and

energy that were embodied during its making becomes entropic, meaning they cannot be reapplied2. To

prevent this loss of valuable energy, reuse of buildings is a better option over demolition. Another

sustainable approach is reuse of historical buildings as it avoids the use and waste of resources in

construction and also the expenditure of energy associated with demolition and redevelopment.

According to Carl Elefante3, “the greenest of buildings… is one that is already built”. A drawback

of reusing existing buildings is that they have been constructed on the standards of the past 4.This makes it

difficult to cope up with the performance standard required in the present day. Hence, historic buildings

require energy codes that are bespoken to consider their historic character and incorporate sustainable

interventions. This would encourage more designers to consider preserving the historical fabric of the

ancient buildings. Hence, such approaches are indicative of sustainable growth and reused buildings often

have lower lifetime costs than newly constructed buildings5.

1, 2 Stein, C. 2010.Greening Modernism: Preservation, Sustainability and the Modern Movement. W.W. Norton and Company.

3Elefante, C. 2010. ‘Valuing our Built Heritage’ at The Heritage & Sustainability Nexus Agenda. Available on

http://www.vancouverheritagefoundation.org/documents/VHF_Sustainability_Symposium_000.pdf. Accessed on 16.05.2012.

4 Wood, B.2006. The role of existing buildings in the sustainability agenda. Facilities, Vol. 24 Issue: 1 pp. 61 - 67

5 Institute of Historical Building Conservation. 2012. Available on http://www.ihbc.org.uk/policy/docs/IHBC%20Valuing

%20Historic.pdf. Accessed on 20.05.2012

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5.2 Building Energy and Carbon Emission

Of the 27% of the CO2 emissions from the domestic sector in the UK, 20% were constructed

before 1919 and 20% between 1920 and 19391. Majority of building types in different climates will take

between 20-30 years to compensate for the initial carbon impacts from construction2. Therefore, suitably

reusing ancient buildings will substantially reduce the carbon impacts arising out of construction activity.

Almost 90% of the buildings we will be living in by 2016 have already been built and hence there is

potential of a significant reduction in energy use in construction 3 by reusing these buildings. While

reusing historic buildings, it may be necessary to refurbish them to meet today’s standards.

A fine example of sustainable refurbishment with minimum carbon emission is the Unilever

House; a Grade II listed building in Neoclassical Art Deco Style, built in the 1920s, located in Blackfriars,

London4. The architects KPF Associates along with ARUP Consultants were able to acclaim the project

with a BREEAM ‘Excellent’ rating for the sustainable refurbishment of the workspaces5.

Figure 1. A. Unilever House Circa 1930s6 B. C. Unilever House- After refurbishment in 20057.

1English Heritage. 2012. Available on http://www.english-heritage.org.uk/publications/energy-efficiency-historic-buildings-ptl/eehb-partl.pdf. Accessed on 20.05.2012

2National Trust for Historic Preservation. 2012. Available on http://www.preservationnation.org/information-center/sustainable-communities/sustainability/green-lab/valuing-building-reuse.html. Accessed on 20.05.2012

3 NBD,2012. Available on http://www.new-bold-design.co.uk/Conservation-Restoration-building-services.php. Accessed on 20.05.2012

4,7 Unilever House, 2012. Available on http://www.less-en.org/?page=CaseStudy-1220. Accessed on 20.05.2012.

5 Kohn Pedersen Fox Associates . 2012. Available on http://www.kpf.com/project.asp?ID=62. Accessed on 20.05.2012.

6 Unilever House, 2012. Available on http://www.netxposure.net/Home/tabid/36/CatalogItemID/337/ CatalogID/1/psnavcmd/CatalogItemDetails/ psmid/368/language/en-GB/Default.aspx. Accessed on 20.05.2012

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By adopting numerous methods such as recycling and reusing the materials from the existing

building and the ones from demolished waste, installation of high performance façades with double

glazing that insulate and shade the new space reducing the need for heat and light, utilising locally sourced

materials and donated furniture and equipment, etc, the building was able to achieve a minimum target of

carbon usage which is 22% better than the building regulations for a refurbished building1. Hence, by

reusing the building waste, the project was able to refurbish its character.

5.3 Impact of materials

A fundamental concern related to energy is the energy consumed in extracting, processing,

manufacturing, transporting and installing building materials or equipment, which is called the embodied

energy and is vital factor to consider in terms of either refurbishing or repairing an existing building.

Realisation of the significance of the embodied energy in historic buildings is one of the main reasons for

their preservation2.

Additionally, traditional raw materials of construction, which most historic buildings are made of,

such as using clay to make bricks, or stone to make slates, implies utilising the natural resources and are

also capable of being recycled or reused3. Present day building standards concentrate on achieving high

insulation values and low energy use4, using modern equipment and materials. For reuse of the vast

majority of older buildings, substantial interventions in terms of materials, to accommodate new lifestyles

while conserving their best features and reducing their running costs are required.

An example where the heritage values were informing the design decisions through intelligent

renovation5 is the Flagship Home in Westminster, a five storey Victorian terraced house from the 19th

century, which is located in a conservation area of the Royal Borough of Kensington and Chelsea6.

1 Unilever House, 2012. Available on http://www.less-en.org/?page=CaseStudy-1220. Accessed on 20.05.2012.

2,4 Stein, C. 2010.Greening Modernism: Preservation, Sustainability and the Modern Movement. W.W. Norton and Company.

3 Carroon, J. 2010. Sustainable preservation: greening existing buildings. Wiley: Hoboken, NJ.

5 Yates, T. 2006. Sustainable Refurbishment of Victorian Housing: Guidance, Assessment Method and Case Studies. BRE Press.

6 Energy Savings Trust. 2012. Available on www.energysavingtrust.org.uk/.../CE192+-+flagship+home+case+studies.pdf. Accessed on 20.05.2012.

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As the building is situated in a conservation area, addition of external wall insulation to the front to

improve the thermal condition of interior spaces was not possible; therefore insulated dry lining was added

on the interior walls. Hence the performance of the materials of the façade improved with reduction of

heat losses through the walls by up to 65%1. The heritage importance of the site also prevented the poor

quality front windows to be replaced. But secondary glazing from inside was added to prevent heat loss

through them( see fig.2b,c).

Figure 2. A. Victorian Terrace House, before Refurbishment2 B, C. Secondary Glazing on main façade-After refurbishment3

1Flagship Homes, 2012. Available on http://www.secureproject.org/download/18.360a0d56117c51a2d30800078402/ Flagship+home_UK.pdf. Accessed on 20.05.2012.

2,3 Energy Savings Trust. 2012. Available on www.energysavingtrust.org.uk/.../CE192+-+flagship+home+case+studies.pdf. Accessed on 20.05.2012.

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5.4 Application of Renewable Energy

The current building scenario requires green and renewable sources of energy to reduce impacts on

the environment, even in operation of a historical building1. Renewable energy is also encouraged for

buildings that may be used sporadically, as renewable energy has the advantage of being stored after being

tapped or fed into a main grid when not required2. The drawback of utilising renewable energy in

historically significant buildings is its incorporation of equipment which is difficult to conceal.

An excellent example of demonstrating how renewable energy equipment can be installed

sensitively in a Grade I listed building from 1684 is the St. James Church in Piccadilly, London (fig 3A),

designed by Sir Christopher Wren. During the restoration, forty photovoltaic panels were installed on the

south facing roof to tap energy from sunlight to generate electricity for lighting and appliances in the

building. The photovoltaic panels were invisible from view from the ground and each panel was supported

on specially designed moulded plastic box weighed down by ballast3. The Energy Savings Trust

encouraged and funded this project as the installation of renewable energy generation equipment posed no

threat to the historical character of the building and could be easily reversed.

Figure 3. A. St James Church, London4 B. Installation of photovoltaic panels on the roof5.

1 Renewable Energy Association. 2012. Available on http://www.r-e-a.net/about. Accessed on 22.05.20122,3,4,5The Prince’s Regeneration Trust. 2010. The Green Guide to Historic Buildings: how to improve the environmental

performance of listed and historic buildings. TSO Stationery Office, London. pp 74-77

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5.5 Social Sustainability

Conservation approaches such as refurbishing and reuse of old buildings involves greater physical

labour than constructing a new building and therefore generates higher levels of investment in local

economies1 and also benefits the community and the environment in the process. These aspects are

indicative of social sustainability.

An award winning project was regeneration of Conway Mills, a Grade B2 19th Century flax

spinning mill in West Belfast. The mill shut down in 1975 after which it became a target of vandalism and

neglect2. In 1996, the local community group acquired the mill for social and economic regeneration, to

restore the mill to reflect its historical and industrial importance to the local and wider community ( see

fig.4C). The regeneration process geared direct local participation of the community in the project, hence

nurturing an interest in the heritage of the area and also promoted opportunities and resources for

economic, social, cultural and educational regeneration for people in the surrounding area3. The building

now houses business units, artists’ studios and local community education centre and a field of

opportunity of jobs in the future4. Hence, the local community revived the building by being attracted to

its historical significance which paved the way for a sustainable future.

Figure 4. A. Conway Mill, 19754 B- Restoration by Community-19825 C- Regeneration 19966 D- Community Spaces7

1 Institute of Historical Building Conservation. 2012. Available on http://www.ihbc.org.uk/policy/docs/IHBC%20Valuing %20Historic.pdf. Accessed on 20.05.2012

2,4 Prince’s Regeneration. 2012. Available on http://princes-regeneration.org/projects-case_studies.php?id=13. Accessed on

20.05.20123,5,6,7 Conway Mills Regeneration. 2012. Available on http://www.bbc.co.uk/news/uk-northern-ireland-15125448. Accessed on

20.05.2012

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6. Adaptive Reuse- A Sustainable Conservation Approach:

A passive approach of conservation that significantly contributes to the economic and

environmental aspect of sustainability is adaptive reuse, which is broadly defined as “any building work

and intervention to change its capacity, function or performance to adjust, reuse or upgrade a building to

suit new conditions or requirements1. The environmental benefit, combined with the energy savings from

avoiding wastage of demolition and construction, carbon emissions reduction, and the social and

economic advantages of recycling a valued heritage building, makes adaptive reuse a suitable approach to

conservation2. ICOMOS in 19993, states that the new use should be compatible with the old fabric, and

any interference to the fabric should be minimised.

A good example of adaptive reuse is the Tate Modern Museum in London, a power station

designed by Sir Giles Gilbert Scott in 19474. In 1992, Herzog and de Meuron, won the competition of

converting the building into a museum, by proposing an adaptive reuse strategy and conserving majority

of the building. Effort was made to make the large spaces more cohesive and attention was paid to

structural repair and also remodelling the spaces to current fire safety standards5. The existing shell of

brick (see fig. 3C) was maintained and the architects capitalised on the advantages of the structure such as

large open spans and provision of day lighting (3B).

Figure 3. A. Initial Drawings, 19476 B- The structure of the Turbine Hall7 C- After occupation-20008

1 Douglas, J.2006. Building adaptation (2nd ed.). Butterworth-Heinemann.

2 Department of Environment and Heritage. 2004. Adaptive reuse: Preserving our past, building our future. ACT: Department of Environment and Heritage, Australia

3 ICOMOS. 1999. The Burra charter, the Australia ICOMOS charter for places of cultural significance. Australia ICOMOS Inc.

4 Tate Modern Museum.2012. Available on www.caa.uidaho.edu/arch504ukgreenarch/.../tateModern2.pdf . Accessed on 16.05.2012.

5,7,8 Tate Modern Museum.2012. Available on http://architecture.about.com/od/museum1/ss/TateModern_5.htm. Accessed on 16.05.2012.

6 Tate Modern Museum Drawings.2012. Available on http://ribapix.com/index.php?a=wordsearch&s=item&key=Wczo xOToidGF0ZSBtb2Rlcm 4gZ2FsbGVyeSI7&pg=6. Accessed on 16.05.2012.

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7. Encouragement from Local Bodies

Sustainable conservation approaches must be adopted by implementing them in the local building

codes and also encouraged through ‘green’ recognition. For example, Leadership in Energy and

Environmental Design (LEED) of the U.S. Green Building Council awards three credits for the reuse of

the existing building materials1. Although some of the governing bodies such as Society of Protection of

Ancient Buildings (SPAB) are strong believers in retaining the pristine character of a building as much as

possible, it disapproves of any interventions, some of which may also be in its sustainable interests.

However, other local agencies encourage sustainable approaches to conservation, like the Heritage Lottery

Fund2, which encourages a sustainable approach to conserving a heritage building, by granting those

funds. The BRE in UK is collaborating with the Rethinking Housing Refurbishment Projects3 which is

looking at ways to refurbish ancient buildings in energy efficient ways. The English Heritage is also open

to sustainable approaches of conservation and has also been involved in recent research in investigating

ways to improve energy efficiency of windows4.

8. Conclusions

To salvage a heritage building from impending deterioration, it is necessary to conserve it. But a

more green approach to doing so must be employed so that both the historical character and the

sustainable factors are fulfilled. Where buildings live as a testament of the periods in which they initially

existed, it cannot be condoned that they also contribute to the deterioration of the environment of the

future. Although, it is the immediate response from an architect to pay respect to the historical significance

of a building by conserving it, indifference to impacts of a collective set of historically significant

buildings on the environment is irrational. Hence a balance is required between the both the factors.

1 LEEDS, 2012. Available on http://www.usgbc.org/DisplayPage.aspx?CMSPageID=221. Accessed on 25.05.2012.

2 Heritage Lottery Fund, 2012. Available on http://www.hlf.org.uk/aboutus/Pages/AboutUs.aspx/. Accessed on 25.05.2012.

3 Rethinking housing Refurbishment, 2012. Available on http://www.rethinkinghousingrefurbishment.co.uk/. Accessed on 25.05.2012.

4 Baker, P., 2011. U‐values and traditional buildings : In situ measurements and their comparisons to calculated values. Historic Scotland

Technical Paper 10,Glasgow Caledonian University, Scotland. Available on www.historic-scotland.gov.uk/technicalpapers. Accessed on

25.05.2012.

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It is impossible to reverse the adverse affects caused on the environment, especially due to

architecture. Although in terms of architectural ethics, the value conserving historic fabric is superior, the

ethics of safeguarding the environment are more holistic and timely. Where opportunities of sustainable

approaches to conservation are possible, the architect must choose it while also respecting the building’s

character. More motivation of sustainability from the governing bodies is needed in the conservation

sector. The buildings that have survived the events of the past need to endure the coming of the future.

9. Bibliography

1. Baker, P., 2011. U-values and traditional buildings : In situ measurements and their comparisons to calculated values. Historic Scotland Technical Paper 10, Glasgow Caledonian University, Scotland. Available on www.historic-scotland.gov.uk/technicalpapers. Accessed on 25.05.2012.

2. Brundtland Commission. 1987. Available on http://en.wikipedia.org/wiki/Brundtland_Commission. Accessed on 20.05.2012

3. Cassar, May. 2005. Centre for Sustainable Heritage, University College London.

4. Carroon, J. 2010. Sustainable preservation: greening existing buildings. Wiley: Hoboken, NJ.

5. Conway Mills Regeneration. 2012. Available on http://www.bbc.co.uk/news/uk-northern-ireland-15125448. Accessed on 20.05.2012

6. Cullen, G. 1961. Townscape. Architectural Press, London.

7. Department of Environment and Heritage. 2004. Adaptive reuse: Preserving our past, building our future. ACT: Department of Environment and Heritage, Australia

8. Douglas, J.2006. Building adaptation (2nd ed.). Butterworth-Heinemann.

9. Elefante, C. 2010. ‘Valuing our Built Heritage’ at The Heritage & Sustainability Nexus Agenda. Available on http://www.vancouverheritagefoundation.org/documents/VHF_Sustainability_Symposium_000.pdf. Accessed on 16.05.2012.

10. Energy Savings Trust. 2012. Available on www.energysavingtrust.org.uk/.../CE192+-+flagship+home+case+studies.pdf. Accessed on 20.05.2012.

11. English Heritage. 2010. English Heritage Website. Available from http://www.english-heritage.org.uk/. Accessed on 20.05.2012.

12. English Heritage. 2012. Available on http://www.english-heritage.org.uk/publications/energy-efficiency-historic-buildings-ptl/eehb-partl.pdf. Accessed on 20.05.2012

13. Flagship Homes, 2012. Available on http://www.secureproject.org/download/18.360a0d56117c51a2d30800078402/ Flagship+home_UK.pdf. Accessed on 20.05.2012.

14. Godwin, P.J. 2011. Building Conservation and Sustainability in the United Kingdom. Science Direct, Volume 20, pp12-21

P a g e | 13

15. Hay, Hergen. 2009. Presentation at Ecobuild London

16. Heritage Lottery Fund, 2012. Available on http://www.hlf.org.uk/aboutus/Pages/AboutUs.aspx/. Accessed on 25.05.2012.

17. ICOMOS. 1999. The Burra charter, the Australia ICOMOS charter for places of cultural significance. Australia ICOMOS Inc.

18. Institute of Historical Building Conservation. 2012. Available on http://www.ihbc.org.uk/policy/docs/IHBC%20Valuing %20Historic.pdf. Accessed on 20.05.2012

19. Jacobs, Jane. 1961. The Death and Life of Great American Cities. Cape, London

20. Jones, L., Elridge, Adam et al. 2008.Retrofitting Soho: improving the sustainability of historic core areas, University of Westminster, London. pp 12.

21. Kohn Pedersen Fox Associates . 2012. Available on http://www.kpf.com/project.asp?ID=62. Accessed on 20.05.2012.

22. LEEDS, 2012. Available on http://www.usgbc.org/DisplayPage.aspx?CMSPageID=221. Accessed on 25.05.2012.

23. Lynch, K. 1964. The Image of the City. MIT Press/Harvard University Press, Cambridge, MA.

24. National Trust for Historic Preservation. 2012. Available on http://www.preservationnation.org/information-center/sustainable-communities/sustainability/green-lab/valuing-building-reuse.html. Accessed on 20.05.2012

25. NBD,2012. Available on http://www.new-bold-design.co.uk/Conservation-Restoration-building-services.php. Accessed on 20.05.2012

26. Rethinking housing Refurbishment, 2012. Available on http://www.rethinkinghousingrefurbishment.co.uk/. Accessed on 25.05.2012.

27. Renewable Energy Association. 2012. Available on http://www.r-e-a.net/about. Accessed on 22.05.2012

28. Semes, S.W. 2009. The future of the past : a conservation ethic for architecture, urbanism, and historic preservation. W.W. Norton, London

29. Stein, C. 2010.Greening Modernism: Preservation, Sustainability and the Modern Movement. W.W. Norton and Company.

30. Tate Modern Museum.2012. Available on www.caa.uidaho.edu/arch504ukgreenarch/.../tateModern2.pdf . Accessed on 16.05.2012.

31. Tate Modern Museum.2012. Available on http://architecture.about.com/od/museum1/ss/TateModern_5.htm. Accessed on 16.05.2012.

32. Tate Modern Museum Drawings.2012. Available on http://ribapix.com/index.php?a=wordsearch&s=item&key=Wczo xOToidGF0ZSBtb2Rlcm 4gZ2FsbGVyeSI7&pg=6. Accessed on 16.05.2012

33. The Prince’s Regeneration Trust. 2010. The Green Guide to Historic Buildings: how to improve the environmental performance of listed and historic buildings. TSO Stationery Office, London.

34. The Prince’s Regeneration. 2012. Available on http://princes-regeneration.org/projects-case_studies.php?id=13. Accessed on 20.05.2012

35. The UK Low Carbon Transition Plan, 2009, pp 6, pp 99

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36. Unilever House, 2012. Available on http://www.less-en.org/?page=CaseStudy-1220. Accessed on 20.05.2012

37. Unilever House, 2012. Available on http://www.netxposure.net/Home/tabid/36/CatalogItemID/337/ CatalogID/1/psnavcmd/CatalogItemDetails/ psmid/368/language/en-GB/Default.aspx. Accessed on 20.05.2012

38. Viollet-le-Duc. 1990. The foundations of Architecture: Selections from the Dictionnaire Raisonne. New York: Braziller. pp195

39. Wilkinson, J.S., Reed, R.J.2006. Office buildings and the environment – the increasing importance of ESD. 12th Annual Pacific Rim Real Estate Conference, University of Auckland, New Zealand. Available on http://www.prres.net/papers/Wilkinson_Office_buildings_and_the_environment.pdf. Accessed on 19.05.2012

40. Wood, B.2006. The role of existing buildings in the sustainability agenda. Facilities, Vol. 24 Issue: 1 pp. 61 - 67

41. Yates, T. 2006. Sustainable Refurbishment of Victorian Housing: Guidance, Assessment Method and Case Studies. BRE Press.