Positive impact: where’s the carbon in my fit-out?

Words: Stephen Hill, Associate Director, Arup

The embodied carbon of construction has shot up the industry agenda over the last few years, as the challenge of climate change and the ambition to reach net zero has started to bite.  This is particularly true in London where the Greater London Authority’s London Plan requires referable developments and refurbishment projects to report embodied carbon impact.  Funders are also interested, with some examples of green finance deals linked to embodied carbon outcomes. As a result, we know much more now than we did about where the carbon is in construction and what we can do to reduce it.

This focus on driving down embodied carbon is starting to influence the re-use market in interesting ways. Because leading developers are willing to pay to reduce their embodied carbon, the value of re-used products is increasing, which in turn makes recovery of materials from strip-outs and demolitions more viable. Raised access floor tiles is a classic example – these are relatively carbon intensive, so the re-used tiles are a sought-after commodity with a price to match.

Up to now the embodied carbon of fit-outs has largely been missing from this revolution, as landlords and developers have been leading the charge. However, that’s starting to change, with some leading developers requiring incoming tenants to calculate and report the embodied carbon of their fit-outs. And the UK Net Zero Carbon Building Standard, which is due to launch later in 2024, is likely to include consideration of fit-out embodied carbon, although the details are yet to emerge.

So, what difference could and should this new focus on embodied carbon make in the world of interior design and construction?

The first priority is to see is more awareness and understanding of the importance of lifecycle thinking. When compared to a building that is designed to last 60 years, and may well be around for much longer, a fit-out generally has a much shorter life. So, the lifecycle impact is as much about how long the item lasts and what happens to it at end of life as it is about the carbon associated with manufacture. Materials and equipment that are more robust, or designed to be demounted, may be slightly higher carbon initially but this will be more than compensated for if they are then re-used over again. And installation techniques also need to reflect this, with mechanical fixings in place of glues being one example of how future adaptation and re-use may be facilitated.

But this isn’t just about re-thinking the initial design. The worst outcome would be to choose more robust or flexible materials, at a cost of slightly higher upfront carbon, only for them to still end up in a skip at the first refurbishment cycle. The second priority is that the focus on embodied carbon turbo-charges the secondary market for fit-out materials and equipment. This market has been around for many years, of course (I’m writing this at home sitting on a second-hand office chair purchased many years ago). But attaching a value to the embodied carbon saving enhances that market, increasing the value of the reclaimed materials and so making more categories of material recovery commercially viable. It also opens the door to different supply models, such as leasing of materials rather than purchase.  The so-called products-as-a-service model is slowly gathering momentum, and the integrated lifecycle planning that it enables brings a range of benefits, including a reduction in embodied carbon over the lifecycle.

So, whatever our role in the interiors market I think we need to be asking ourselves – how big is my slice of the embodied carbon pie?  And importantly how can I make it smaller? Because if we are to reach net zero carbon, as we surely must, we are going to need to find our way to a much smaller pie.

Hill is an Associate Director at Arup and a sustainability consultant with 25 years’ experience. He specialises in the development of carbon and sustainability strategies for buildings and portfolios across a range of sectors, and is passionate about the climate crisis and strong advocate for the property sector’s transition to Net Zero. He is a member of the NABERS UK Independent Design Review panel, and is Arup’s representative on the BCO ESG Committee.