Delivering a sustainable City landmark

Early engagement pays sustainability dividends

We began working on the project in 2019, helping to shape the design and construction methodology, providing sustainability advice and supporting programme development.  

Thanks to our early involvement and collaboration with British Land at the design stage, we were able to engage with the wider supply chain to improve design efficiency and propose innovative low-carbon materials: 

• In partnership with our piling contractor, we rationalised the foundation design, reducing pile diameter from 2.4m to 1.8m to optimise material use and used steel manufactured in an electric arc furnace for around a third of the plunge column piles, which cut embodied carbon by 15%. 
• Together, we also pioneered basalt reinforcement in the temporary works. Made of volcanic rock, this is up to 60% lower carbon than steel reinforcement in its manufacture. 
• Working with the steelwork contractor, we’re using 95% XCarb steel in the superstructure; a product manufactured by electric arc furnace with 100% recycled steel and powered by REGO-backed renewable energy, saving around 5,000 tonnes of CO2e versus traditional blast furnace steel.  
• The facade features aluminium produced using renewable power, saving around 1,900 tonnes of CO2e versus an average European aluminium product. 

At the final design stage of this project, we were able to reduce the embodied carbon emissions from 755kg to 656kg CO2e per sqm. 

Deconstructing for reuse

Work began on site in July 2022 with the soft strip and deconstruction of the existing two 10-storey buildings, an operation based around circular economy principles. 

This saw nearly 25 tonnes of structural beams extracted, cleaned and tested; materials which were then warrantied for reuse. Approximately 2,500m3 of concrete was recovered, crushed and reused in the foundations and around 9,500m2 of raised access flooring removed and stored for reuse. 

Reducing programme by going top-down

The scheme is being delivered using top-down construction. This meant that while the superstructure was rising more than 100m above street level, the team were also busy simultaneously digging out 36,500m3 of earth to form three basement levels. It’s an approach that helped shave nine months off the project’s programme. 
 
Once Basement 1 was constructed up to ground floor, these two floors were locked in and the team began building two further basement levels top down.