Around the world, regulations are changing, as our industry understands that the carbon emissions from producing and transporting the materials used in our buildings can make up as much as 50% of the carbon they will emit over their whole lives. More importantly, that embodied carbon is entering the atmosphere today, getting us closer to the climate tipping points we need to avoid.

Some planning authorities in the UK now require that before you knock down a building and replace it, you prove that this makes more sense than retrofitting it, based on the lifetime carbon impact. That is starting conversations all around the country. Planners, project teams and clients are beginning to question whether demolition is the right thing to do, and whether they can instead reuse the bones of an existing structure, its facade, MEP or other materials.

Technically, it’s much easier to start with a blank canvas than to mould an existing building to meet a new brief. There is inevitably some compromise with retrofitting, whether that’s aesthetic or in terms of flexibility or floor space. So it’s about going back and testing that brief against what we really need, and seeing if we can better align it with what’s available. But even if you knock a building down and start again, you still have to work within the same footprint. And you can be equally, if not more, constrained by the need to derive the greatest possible value from the site.

We’re starting to move away from the perception that “new” equals “premium” and see the value in existing buildings and their place in a circular economy. Even an obsolete structure can have useful components – if it’s demolished carefully, the materials from that “donor” building could be reused in a “recipient” somewhere else. If a client has a campus, an estate or a portfolio, that isn’t too difficult to do.

 

Today’s retrofits can teach us about circular economy design

Right now, we’re in the challenging position of needing to upgrade a massive proportion of our building stock if we’re going to meet net zero. We need to learn from today’s retrofits, designing new net-zero buildings to make it much more straightforward to convert them to other uses in the future – for example, with higher ceilings or spare capacity in the MEP layout.

We also need to design in climate change adaptability, so that our buildings will still be fit for purpose in a warmer world with more extreme weather events. A building might not require mechanical cooling today, but it might do in 20 years to remain comfortable. There’s always a balance, not only between operational and embodied carbon, but between embodied carbon and future flexibility. Some decisions might add upfront carbon today, to achieve the goal of much greater reductions down the line.
 

Retrofitting is not the end of the story

We need to apply circular economy principles to retrofit projects in exactly the same way. We need to think harder about how they are put together, and use standard sizes for components so that they can be easily dismantled and reused. It might be as simple as fixing mechanical equipment with screws and bolts rather than adhesive, so that it’s not so destructive or wasteful to take it apart. We don’t need simply to retrofit our existing buildings – we need to do so in a way that makes it easy to do the same thing again and again and again.