The panel agreed that the best way for heritage buildings to survive is for them to be used, and the best way to keep them occupied is to flex their usage to our current times.
Charlotte Robinson of Purcell Architects said that when it comes to retrofitting, a project needs to meet modern-day user expectations.
In decades gone by, people might accept studying or working in a drafty building. Not so much today.
Users require totally different performance from our buildings now than in previous centuries, and for these buildings to continue to stand the test of time for the next 600 years, they have to be able to be usable and durable.”
Peter Vellet felt that archaeology and heritage consultants often put too much emphasis on the negatives and not enough around the potential to “make buildings better.”
A number of the delegates felt that the subjective nature of listed building consent is problematic.
They want to see a more consistent approach from the planning authorities around how Net Zero objectives for heritage buildings are balanced against the concept of ‘harm’ to a heritage building. The desired approach has to be framed in a way that's based on science.
The science of climate change doesn't necessarily require a building to be Net Zero. It requires the built environment to reduce its emissions by a certain proportion year-on-year up to whatever the target is for Net Zero for that local authority.
The panel discussed how it's about re framing this conversation not as delivering a Net Zero heritage asset, but delivering a heritage asset that is on the science based trajectory towards Net Zero which will be higher energy use than a new build and it's accepting that difference as well that's important.
The panel also reflected on the reality that the embodied carbon in a heritage building is already there – the building has been constructed.
If these buildings last for hundreds of years, is consideration given to the reality that new builds now have a nominal design life for perhaps 60 years?
They may have a shorter or longer useful life, but that needs to be given consideration. Heritage buildings are sustainable because they last longer and are inherently circular in sustainability terms. ‘Circular’ means keeping materials in use for as long as possible.
There was much agreement that the issue came down to the question of whether an intervention results in harm or substantial harm to the building, but also understanding that in the context of a streetscape or a cityscape.
It’s about the specifics of how do we improve the fabric performance. How do we upgrade the heating systems without unintended negative effects such as increased moisture in the building and humidity and lack of ventilation and those kind of things that can happen as a result?”
Tim Clement advised that listed buildings can obviously benefit from the latest innovations around heating systems, but many innovations are designed for new builds.
He explained: “A low-temperature hot water heating system requires a great performing fabric which we don't normally have in listed buildings.”
The discussion led to how the industry is looking to adapt innovations designed for new-build to listed buildings rather than seeing innovations coming through that are specifically geared towards heritage or listed buildings.
We need to keep innovating – we are at the beginning of this journey and nobody has all the answers, so we need to keep learning and improving.”
