“Reduce, re-use, recycle” is a well-established sustainability slogan. But how can re-using existing buildings help tackle the climate emergency? Our Director of Heritage & Reuse Kevin Balch looks at the issues and advantages of creatively re-using what’s already in our built environment.
In previous decades, re-using existing buildings was not necessarily at the forefront of people’s minds, and certainly not for reasons of embodied CO2 or the climate emergency. People have been aware of carbon emissions for some time but probably more in the context of building regulation compliance. Even then, this was generally seen as one of the many ‘hoops’ to jump through for development to happen.
Thankfully, things have changed rapidly in recent years. Terms like ‘cradle to grave’ and ‘lifecycle costing’ are now mainstream and often heard in the context of pledges to address the climate challenge and biodiversity concerns. And most recently, the impact of Covid-19 has put fresh focus on the importance of the local environment and community. We know our well-being is intrinsically linked to our environment and the natural biological systems that support us.
Energy use and existing buildings
Carbon savings in the built environment can be found in two distinct areas: firstly, the amount of carbon used to build it, and secondly, the amount of carbon to run and maintain it. Unsurprisingly, the calculations of each can be complex and need to take account of the sourcing of materials, distribution of the raw elements, the energy to process these and shape them before transporting to site. The maintenance costs need to make assumptions on changes in future energy sources, the lifecycle of components and finishes that get renewed during the life of the building (and if they themselves can be re-used).
‘Mining’ our existing manufacturing legacy to reclaim precious metals and raw ingredients in place of mining natural ingredients from the natural world (gold reclaimed from electronic devices rather than digging it up, for example) has been an interesting development. So, what are the issues facing the re-use of existing buildings?
As we all strive for systems that take cyclical manufacturing systems of recycling to a new level, it can be all too easy to overlook the simple and the obvious – to make more use of what we have already.
Established networks
Existing buildings are often already served by transport and communication networks and are situated in places where we would like to live and work. So the carbon already expended to manufacture the steel, masonry and concrete in the first place should be assessed for re-use before demolition.
Framed buildings are inherently adaptable, easily converted and relatively straightforward to insulate well (which, of course, is the first golden rule).
Insulating issues
More traditional buildings with load-bearing masonry are incredibly good at maintaining a stable internal environment in an increasingly unstable climate, given their high thermal mass. It means adding insulation internally needs a bit more care, because it can lead to long-term moisture levels rising. In the field of conservation and heritage, it is common practice to use materials which do not inhibit this moisture transfer. Natural insulants and lime all play a critical role here.
The sound techniques of thermal improvements to listed building are well tested and, of course, are just as appropriate to all existing buildings as they are to those on the protected register.
The right advice at the right time
But what about time and money? It is true that many people see working on listed buildings as complicated and problematic. However, it needn’t be if you approach the project with the correct mindset and are guided by the right professional advisors.
What’s next for creative re-use?
Some structures will be more appropriate for a particular use than others, such as buildings with a high dependency on environmental conditions, access or comfort. We are likely to see this reflected in planning policies which then actively encourage (and speed up) certain conversations based on carbon or energy in the planning approval process.
The creative re-use of buildings brings an enormous advantage with the structure and infrastructure being largely complete before you start. Design teams are already developing and using tools which allow near real-time feedback of the impacts on their design choices. It’s crucial that these tools are more widely understood by the whole development team to allow meaningful discussions and decisions at appropriate times.
Legislation will continue to advance quickly in this area and it is likely that future developments will all be tested by various metrics at planning stage. This will help assess thermal efficiency and embodied carbon, which will no doubt help change how we as designers all ‘value’ what we do.
– By Kevin Balch