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There is growing momentum behind the movement for a retrofit first approach to future development. It’s noticeable that commentators are taking much greater interest in interrogating decisions to demolish existing structures, mirroring changing sentiment around our increasingly indefensible disposable society.

For someone with a career-long interest in driving out inefficiency, waste and carbon from our construction processes, this enhanced profile around re-use is most welcome.

However, there’s a major elephant in the room when it comes to building on increasing interest in this topic, and it’s around how we quantify embodied carbon and other pertinent data from re-used materials.

If we can’t measure the stuff – then we can’t be evangelical when we deliver a smart solution that sequesters carbon; or steer our customers and supply chains towards better products or methodologies with a reduced carbon impact and increased circularity.

To work on the Entopia ºÚ¶´ÉçÇø for the Cambridge Institution for Sustainability Leadership (CISL) was to be at the leading-edge of a fabric-first, deep retrofit office redevelopment project. Every element of this project has been carefully scrutinised to deliver the highest possible standards for exemplar low-carbon, ethical construction and optimised performance.

Having the requisite data for reused materials, perhaps in a materials passport, will help de-risk the use of reused materials

Driving down embodied carbon was a key component of the scheme, and despite the extensive use of BIM, the process of establishing a true carbon baseline proved clunky and inefficient. I know from painful experience that this is a major impediment to progress and widespread industry adoption. There is a significant cost if we don’t grasp this issue now and create a simplified system for measurement and evaluation.

My vision is for a more efficient link between the component libraries of embodied carbon and digital tools (e.g. BIM, estimating tools) for every element that we either retain or incorporate in a building. This could of course form part of the material passport system that I’ve long advocated as a standard for every project. This, in tandem with an established and growing market-place for reused materials, would really shift the dial in lowering the embodied carbon of the material choices we make as an industry.

We’d need to iron out details on quantifying carbon from retained elements of course, and work with manufacturers to ensure regular specification updates, re-warranty, and quality control as products evolve and reuse becomes more common. Having the requisite data for reused materials, perhaps sitting in a materials passport, will help de-risk the use of reused materials and provide the confidence needed for more widespread adoption. But it’s a move that sets us up for a simplified framework that will drive product improvements, more widespread adoption of product specific Environmental Product Declarations (EPD) and provide greater transparency.

Returning to the Entopia ºÚ¶´ÉçÇø, the embodied carbon calculations, undertaken by Architype, actually revealed that one of the most advantageous ways to mitigate carbon on the project was the reuse of the existing raised access flooring. This outcome was established as part of the design process, and provided an opportunity for the client to make decision based on more than just cost and time constraints.

Being an exemplar scheme of course, you wouldn’t expect us to stop right there. The calculations revealed that any floor covering would tip the balance outside our targeted parameters for carbon. CISL listened to the feedback and the Entopia ºÚ¶´ÉçÇø now has uncarpeted raised access floors throughout – and this solution works well for the client’s team, and is far less incongruous that you might first imagine.

Anna Foden, ISG’s Head of Sustainability for UK Fitout and Retail