Handle with care: retrofits are full of surprises and architects have lots to learn

With the increasing urgency surrounding the climate emergency we should all be looking for ways to try and reduce our carbon footprints or mitigate some of the climate impacts of our practice as an architect. The recent controversies surrounding Pilbrow & Partners’ proposals for the M&S flagship store on Oxford Street call to mind other recent debates around replacing older buildings.

While in some cases the carbon efficiencies of a well detailed and serviced new-build can, in the long term, mean an overall carbon saving over retrofitting an existing building, in the vast majority of cases demolishing an existing building and replacing it will lead to higher carbon costs.

On the face of it, it is simple – upgrade the fabric and servicing a bit and reconfigure the inside to suit a new purpose… but we all know that there is so much more to it than that. Any existing building, of no matter what age, will throw up multiple surprises en-route.

I have not done too much work with existing buildings in my career to date but recently had the opportunity to speak with conservation architect Libby Watts. She trained as an architect in the usual way but undertook the SPAB Lethaby Scholarship programme to get a hands-on understanding of conservation by travelling the country and learning from craftspeople and conservation experts on sites across the UK. 

If you destroy something, you do not get an opportunity to try again – and you have destroyed hundreds of years of history

One of her observations was that standard architectural education does not equip us well for working on historic building fabric. Existing buildings, she noted, need to be handled carefully, especially very historic ones; you need a clear understanding of how materials work and interface with each other, how best to do the work; what retrofits are appropriate and which will not work.

If you destroy something, you do not get an opportunity to try again – and you have destroyed hundreds of years of history. She noted that it was only in beginning to learn the materials “by hand” as she worked on site during the scholarship that she gained the full confidence and knowledge to detail appropriately, despite having worked in conservation for several years prior to the scholarship. 

Working with historic building fabric also throws up problems that we should all be considering around the sourcing of materials. The local materials we used to build with in the UK are often no longer available – we no longer commercially grow the correct type of wheat to make our own thatch, and our commercial timber production is much lower, leaving us to grapple with the comparative knottiness of so much eastern European timber.

Libby explained that some cathedral stone repairs, with stone sourced from abroad, in the 1980s had actually increased the rate of decay of the original stone. We are now trying a stone shipped from a quarry in France, visually similar and of a similar type to the cathedral’s stone (which had been quarried from a now defunct pit just a mile or so from the cathedral), but at a molecular level the two are very different. As yet we cannot know whether this has solved the problem or worsened it.

Truly sustainable additions and alterations should preserve the fabric of the existing building and add onto it in the most compatible and sustainable way

Of course, these are very specific examples for particularly historic buildings, but the point holds true for retrofits or adaptations of more modern existing buildings. Truly sustainable additions and alterations should preserve the fabric of the existing building, and add onto it in the most compatible and sustainable way possible – considering the provenance of the materials and how they have reached the building site. 

These discussions cannot be had by the architectural side of the project team alone though. Engineers, contractors and other consultants all need to be thinking more collaboratively and holistically – upskilling and thinking outside of the accustomed norms.

Libby’s daily practice sounds a lot more collaborative than mine. While I am on site and do work with engineers, I am currently working on new buildings, which are comparatively “business as usual”. We collaborate, but to an extent all have our own silos of responsibility.

Libby’s team dynamic sounds like a complex puzzle in which contractor, engineers, surveyor and architect must all work much more closly together in order to succeed. If we are all to embrace the carbon saving opportunities associated with retrofits and reuse of existing buildings, I think there is a chance that project team culture, especially that associated with large scale and more commercial schemes, will need to change. 

There is always talk of architects reclaiming their lead role on site but, as Libby so aptly demonstrated to me in tales of her practice, it was not until she went out and learnt part of the jobs of all of the people on her team that she was able to lead it. In a micro way I think she has demonstrated the solution to some of the macro problems that architects face.

It is not just the future of our profession that this kind of upskilling could help, but the planet as well. If only there were schemes like SPAB’s scholarship that were applicable to less niche areas of practice!