Circular Economy in the Built Environment – Reflections & Case Studies
It’s been 4 years since The Ellen Macarthur Foundation published guidance on circular economy policy in London. We’re now lucky to have some case studies to illustrate what we mean by a “comprehensive approach to circularity”.
But just how far have we come?
According to a recent report, two of the four key industries responsible for carbon overshoot are associated with the built environment. While we still have far to go, the decline in cost of resources in the last 100 years is shifting, as a result of reaching peak supply of materials, combined with growing demand in emerging economies. The tipping point in resource cost should propel us forward.
Back in May Club Peloton organised a session bringing professionals from the built environment together for a panel discussion reflecting back on progress made since the foundation’s guidance was shared. The event, hosted at our Reeds Wharf London studio, welcomed engineers and architects working on projects that involve the salvaging and upcycling of materials, including our own team here at Civic Engineers, Fore Partnerships, Webb Yates, Heyne Tillet Steel and AHMM.
The purpose of the session was to put forward practical examples of how we’re implementing a circular economy. The following speakers shared their case studies:
- Simon Hatherley, Senior Building Performance Architect, AHMM
- Tom Webster, Director, Webb Yates Engineers
- Sarah Trahair-Williams, Associate Director, FORE Partnerships
- Gareth Atkinson, Director, Civic Engineers
- Laura Batty, Associate, Heyne Tillett Steel
- Chaired by: Judith Sykes, Useful Simple Trust
To kick off, Simon Hatherley, AHMM, opened by sharing insight from a research project with UCL’s Institute of Environmental Design and Engineering, looking at approaches to developing large-scale, net zero carbon buildings and how we define them.
“Over the course of the research a significant theme was the interrelationship of the circular economy with delivering net zero. Consideration of upfront embodied carbon and material reuse over the whole lifespan of a building and the capacity of a design to support the recovery of materials at the end of a building’s life are critical. The research took a whole life carbon approach considering material passports, design for disassembly and long-life loose fit.
Simon added, “there’s a data infrastructure aspect to delivering net zero carbon. We need to ensure we capture the data we put into buildings and ensure we are able to pull key data out of existing buildings.”
1 Broadgate, currently being developed by British Land, while a demolition and rebuild, had an interesting approach to the circular economy. The Madaster platform was used to capture and quantify circular economy information about materials specified. This approach, considering the circular economy, led to some interesting design responses: one was re-using the external stonework of the building demolished on site for internal finishes like terrazzo floor tiles.
Gareth, Sarah and Tom shared insight from their interconnected projects, starting with the retrofit of 318 Oxford Street, a retail store Civic Engineers is transforming into a multi-use space including gym, office space and restaurants.
“We’re having to create some additional circulation, because of new uses – cutting holes in the building and taking floors off so we can put more on,” Gareth shared. The 1930s building is primarily constructed from steelwork and precast concrete slabs.
Photos from the 1930s were incredibly illuminating, allowing Civic to discover the name of the steel contractor and find the fabrication books. It turns out the steelwork in the centre of the building was completely solid.
Auditing the steelwork helped understand what was available. Many sections had extra plates attached to make them stronger. We tested strength – which typically came back at S235. Today, the grade is around S355 – “a little bit weaker, but still very usable”, Gareth said. The columns are currently on site ready for the fabricator.
Serendipitously, a new home for the beams was brokered on the back of a bike, at a related Club Peloton event. Gareth and Basil Demeroutis, Managing Partner at FORE Partnerships, were bemoaning the lack of joined up thinking in the industry around circularity, and hatched a plan for FORE to purchase 20 tons of steel beams to use at their TBC.London development.
Tom Webster, Webb Yates took the baton to explain how he repurposed the former department store’s steel beams for Tower Bridge Walk, in Bermondsey. “We have two types of steel work on the project – steel from the donor building, and steel from Cleveland that has lost its provenance and can’t be sold on the open market.”
Using design guidelines as a reference, Webb Yates were looking for steel that wasn’t badly corroded and didn’t have evidence of much plasticity. “Identifying defects is a really key part of the process, existing buildings are used, cut, carved, and have services cut through them.”
Sarah Trahair-Williams, FORE Partnership added “sustainability is at the heart of all we do. We want to use as much steel as we can because it’s important: if steel was a country it would be the 4th largest polluter of carbon. This work makes a big difference.”
A need for more brokerage companies like Cleveland was identified – they don’t have much stock and there’s so much demand. It’s important to get more contractors and supply chains on board.
Sarah elucidated, “part of my job is talking to letting agents, and saying, you’re not going to have a shiny new floor. It won’t be perfectly polished, but it’ll have a story to it. As a society, we’ve got to start talking about this. Do we notice the defects? Are imperfections a bad thing?”
Laura Batty, Heyne Tillett Steel, shared her reuse case study, 7 Holbein Gardens. Completed in 2023, it’s the company’s first experience of a complete project that incorporated reuse steel.
“We understood the sticking points from the beginning, which has helped us propose reuse of steel on a lot more projects”. Unfortunately, reuse of the steel from the site didn’t fit with the timeline. In the meantime, the client identified sites in their portfolio that might fit. “Steel was procured from the old US Embassy and the Biscuit Factory, and we were able to send it off to get tested and warranted in time.”
“Overall”, Laura summarised, “we shouldn’t be aiming for 100% reuse, we should be aiming for as much as we can. Don’t throw the towel in if something goes wrong at the last minute. Some is better than none.”
How do you get from serendipity (brokering on a cycle ride) to something more scalable?
Gareth: “It’s corny but the Club Peloton family helped. I already knew Tom, and the relationship was there. Working collaboratively across practices can really help us in the early days of steel reuse. As more developers have to develop with less and less carbon, they’ll be looking towards recycled materials – and then it starts to become financially profitable.”
Laura: “Crash testing steel reuse and sharing information is vital. Getting together and talking is the first step.”
Sarah: “Not enough people are talking about embodied carbon. Using guidelines that already exist like LETI are great, but asking clients if they’re really looking at embodied carbon in construction, not just use, is important.”
How much are clients engaging with material banks as a philosophy?
Simon: “The circular economy has many different components. Our clients were on board with the concept; however, a challenge was capturing all the elements of this approach”.
How interested in the testing regime were your insurance providers?
Tom: “Not that interested! As long as we followed the technical guidance we were okay. Our steel from 318 Oxford Street had high levels of imperfections – so we incorporated the imperfections and downgraded the steel. The engineer needs to show diligence in terms of inspecting the work.”
How much of your testing rejected the steel?
Tom: “Testing doesn’t reject steel, testing tells you what the steel is. It’s for us to make a decision on whether we want to use it. All of it passed our requirements, and of course, some was bent and buckled so we didn’t use it. About 40 tonnes of steel was supplied and 20 tonnes went back into the building.”
The room we’re in is an enlightened one. How do we get this out to wider adoption?
Laura: “Carbon tax.”
Simon: “We need policy and culture change, considering how we treat reuse of materials. We’re constrained by our current physical and digital infrastructure.”
Sarah: “We need eBay for construction projects! But also, talk to your clients and tell them what exists – have numbers ready. You don’t pay VAT on new builds – so we almost have a reverse of a carbon tax at the moment. I heard we tax retrofits because you can’t tell the difference between DIY at home versus work like ours.”
Tom: “We have all the responsibility to make sure clients don’t just recycle material and pocket the money.’
The Government has a lot of real estate in London – do they need to retrofit their own portfolio? How do we get this idea into the treasury?
Tom: “The government isn’t invested in reducing embodied carbon because nothing is manufactured here anymore. The carbon cost is elsewhere – that’s why the UK government doesn’t care. If we calculated the cost at the point of placing carbon, large importers of materials like the UK would get the heat. That would create a big change in mindset and they would care a lot more!”