Watch our webinar, in partnership with The Rooflight Company, which explores the challenges involved in adapting historic buildings to meet contemporary standards of comfort and environmental performance.
An increasing awareness of the carbon cost of demolition has given new urgency to the challenge of finding creative ways to adapt and reuse historic buildings. Four speakers offered different perspectives on the challenges involved.
Henrietta Billings, director of SAVE Britain’s Heritage, described SAVE’s campaigns to prevent demolition with reference to two high-profile central London case studies.
The first, Richmond House in Whitehall, is a Grade II* building by Sir William Whitfield constructed in the 1980s – one of the 0.02 per cent of the UK’s listed buildings built since the war. SAVE objected to proposals by AHMM to demolish most of the building to accommodate a replica of the MPs’ chamber at Palace of Westminster for temporary use during restoration works at the House of Commons. As well as lobbying MPs about the financial and environmental costs of the project, SAVE commissioned Mark Hines Architect to develop an alternative scheme demonstrating that the temporary chamber could be constructed in the courtyard of Richmond House without the need for demolition.
Speakers (from left to right): Oliver Smith, Catherine Croft, Henrietta Billings, and Peter Daniel
The second case study concerned proposals to replace Marks & Spencer’s flagship store on Oxford Street with a building by Pilbrow & Partners. Built in 1921, the building belongs to a long tradition of prestigious department stores that have shaped town centres across the UK. SAVE’s campaigning included targeting Marks & Spencer’s leadership team with the message that these demolition plans are at odds with company’s much-lauded sustainability goals.
‘Departing Stores Emporia at Risk’ report published by SAVE Britain’s Heritage (cover image courtesy of Steve Poole)
Oliver Smith, director of 5th Studio, presented the practice’s retrofit and refurbishment of the Grade I listed New Court, Trinity College, Cambridge designed by William Wilkins in the 1820s. The practice adopted a three-step strategy to reduce emissions: using a fabric-first approach to halve the demand for energy; doubling the efficiency of the systems using that energy; and halving the carbon in the energy supply. It also restored the historic facades and upgraded the interiors in line with current standards of performance, introducing timber wall panels and fitted furniture concealing service distribution and lighting.
The highly accomplished refurbishment of Grade I listed New Court at Trinity College, Cambridge, by 5th Studio and Max Fordham has reduced the energy consumption and carbon emissions by 80 per cent (ph: Timothy Soar)
The application for listed building consent was framed as three questions: What are the heritage values of the existing buildings and their relative significances? To what extent are we going to harm or benefit those values? And, crucially, how are those outweighed by benefits to heritage or other public benefits, such as CO2 emissions, and the lessons to be learnt from monitoring and research?
Interior view of New Court (ph: Timothy Soar)
Consent was granted at the first attempt and Cambridge City Council has now adopted this strategy as policy. The college is reporting that its energy use is down by 80 per cent from pre-refurbishment levels and student feedback is overwhelmingly positive.
Peter Daniel, Product Innovation Director at The Rooflight Company, ran through some of the issues involved in combining performance and historic authenticity, explaining how the company’s modern Conservation Rooflight combines double or triple glazing with features that mimic the appearance of cast iron Victorian rooflights and use new materials – such as silicon instead of putty – to deliver longevity and performance while replicating the details of their historic counterparts.
The Rooflight Company’s Conservation Rooflight combines modern performance with a traditional aesthetic (ph: Dan Abrams)
Daniel offered advice on calculating environmental performance, pointing out that focusing on centre pane values could be misleading, and that the true U-value of the window is a combination of heat loss through the glazing, through the frame and, crucially, at the junction between the two. This ‘frame factor’ is particularly relevant when a window is composed of several smaller panes of glass. He also explained that thermal performance can be improved by designing rooflights that sit flush with the roof – rooflights that sit proud of the roof are more exposed, hence reducing the external temperature of the frame.
Redevelopment of the Brutalist Park Hill housing estate in Sheffield by Hawkins\Brown and Studio Egret West (ph: HawkinsBrown)
Twentieth century problems
The final speaker, 20th Century Society Director Catherine Croft, explained how the Society is increasingly citing environmental issues as an argument against the demolition of buildings of particular architectural or historic interest.
Calling for more ‘meaningful’ research into the comparative costs of retrofit versus demolition, she noted that much of the work carried out by organisations such as Historic England is applicable to solid masonry buildings designed pre-1914. Modern buildings operate in a very different way, particularly in terms of how they deal with water and the movement of moisture. Acknowledging that the combination of deep plans, mechanical ventilation, lightweight construction and extensive glazing make many 20th century buildings challenging to retrofit, she recommended ‘Managing Energy Use in Modern Buildings – Case Studies in Conservation Practice’, published by Getty Publications in 2021, as a particularly useful guide.
The over-arching message from the event was that demolition must become the exception rather than the norm, and that it should only be employed as a last resort. To quote, Carl Elefante, former president of the American Institute of Architects, “the greenest building is the one that already exists.”