The future of built heritage in a Net Zero Carbon society
The UK has a rich and diverse built cultural, historic, and architectural heritage. As a society we choose to protect and preserve this heritage, i.e., places and buildings of special interest, for the benefit of future generations. Their intrinsic value is recognised through legal protections and mechanisms such as the National Heritage Lists and Conservation Areas.
Currently there are over half a million statutory listed buildings in the UK, a similar number are locally listed or within the 100,000 Conservation Areas, which equates to approximately 2-3% of the total number of buildings and area of land. 8% of listed buildings are nationally or locally significant (Grade I or II* in the case of England), with examples ranging from the 14th century Front Quad at New College Oxford to the 20th century Lloyds of London Building, but the majority are of a lesser significance (Grade II).
More buildings and areas are being protected each year and given the new focus on retention and embodied carbon it is not difficult to foresee, rightly or wrongly, heritage lists growing at a higher rate in the near future. Indeed, all new buildings that we now design and build using precious natural resources should be well designed, built to last and ideally good enough to be listed.
Reducing embodied carbon in the construction sector is a vital part of our strategy to meet our legislative goal of achieving a Net Zero Carbon society by 2050, but so is our need to reduce operational carbon, or energy use in buildings. Thankfully in most retrofit projects, recent legislation and regulations now mandate a need to improve the fabric and general energy performance of existing buildings over time, but these requirements are not strictly applied to heritage assets, where interventions are only consented if they are shown to not significantly alter the character or appearance of the building. This evaluation can be quite subjective, particularly on Grade II and Conservation Area buildings, where the specific interest and value of the buildings is often less clearly defined or understood. Without a clear set of guidelines on how to value assets, their components and their future value, conservation officers tend to err on the side of caution and not approve the application of significant carbon reduction interventions, such as fabric enhancements.
Indeed, conservation officers often fail to recognise that the aims of conservation and sustainability are closely aligned. Both need buildings to continue to be loved, used, and maintained, but in a decarbonised economy successfully achieving this will require a change in the way we view and value heritage assets and how we support their protection.
Preserving 2-3% of buildings does not sound like it will have a significant impact, but in the world of Net Zero it is significant, particularly given the fact that most heritage buildings are uninsulated, leaky, and single glazed pre-1900 buildings. If the carbon emissions of our heritage assets are not reduced, then do other retrofits and new builds need to be collectively carbon negative to help offset these emissions? How do we share out that requirement in an equitable way?
At present, the responsibility for funding the operation, maintenance, and preservation of our most precious public assets rests largely with the owners or occupiers, who are often charities and public bodies with limited budgets. Whilst they have access to some public grants to support them with the cost of careful and considered refurbishment works by specialist contractors, at present this support is thinly spread, funds are not large enough to support major decarbonisation schemes and unlike new build projects, funding is diluted by a requirement to pay VAT.
As the wider global economy decarbonises, energy, carbon and material prices are likely to rise in the short to medium term, and therefore the burden of operating and maintaining old inefficient buildings may become too great. Therefore, if we decide as a society to not allow a custodian of a heritage building to reduce their operating costs through efficiency improvements, then we need a mechanism to support them with their future costs and offset their carbon, to ensure they are able to continue to operate the building and lengthen its useful life.
Alternatives include mothballing buildings and using them for filming or other infrequent events/visits that do not require significant energy use, as was the case for the Farmiloe Building, in Clerkenwell, before its recent refurbishment. Or perhaps making the building itself an exhibit within another more efficient new exoskeleton, in a similar but more permanent vein to Carmody Groake’s Hill House project, or perhaps a more carefully considered and efficient version of the Grand Théâtre De Quebec. Extreme scenarios perhaps, but there is unlikely to be a one size fits all solution.
Mark Skelly is the founding director of Skelly and Couch.