A close partnership between architects and structural engineers is essential, not just for great design but for low-carbon buildings too, says Tanya de Hoog
The greatest contributor to embodied carbon in buildings is most often the structure and foundations, followed by cladding. So optimising and reducing embodied carbon is a critical aspect of design.
Accelerating progress requires every discipline in the design, construction, client and owner chain to contribute. With embodied carbon, the structural engineer is at the front of the conversation.
Holistic and balanced design is essential as embodied carbon cannot be considered alone. It must be addressed alongside safety, resilience, longevity, quality of space and place, supply chain, constructability, cost and schedule.
IStructE members must first consider whether it is possible not to build at all, or to reduce demolition and increase building reuse. As this is not always possible, extending materials life follows.
Beyond designing for the longevity of materials and their potential future reuse, the building’s end-of-life phase is also important for a circular economy.
Finding new, even non-structural use for material at the end of its life again reduces embodied carbon. It is common to focus on reducing embodied carbon with new materials, and we must extend thinking and knowledge to whole life use.
Redevelopment of Wimbledon No 1 Court starts with the foresight of the engineers and design team for the 1990s arena. Extra structural capacity was designed into the lift cores and their foundations in anticipation of a potential addition. Due to this forward planning it was possible to retain and expand the seating bowl nearly 20 years later.
Refurbishment works were highly co-ordinated between architect, extensive MEP requirements and optimisation of the steel roof by the structural engineers to balance the competing requirements.
Early contractor involvement allowed circular economy principles to be adopted by reusing large diameter steel pipe sections from the oil and gas sector for vertical column supports and part of the primary roof trusses.
Forward planning enabled Wimbledon No 1 Court seating bowl to be expanded 20 years later
Willingness of the design-build team to collaborate and try new things, coupled with each discipline bringing a thorough and deep technical rigour, allowed embodied carbon savings. Retaining the structure gave a 9000 tonne CO2e saving. The new structure cut around 10% of its embodied carbon through roof steel design optimisation, reuse of steel pipes, innovative construction and temporary works. It demonstrates the significance of collaboration, and the feasibility and impact of these approaches.
This project shows that to accelerate the reduction of embodied carbon in buildings, structural engineers and architects must be at the forefront of technical knowledge and innovation in lower-carbon materials and design.
Being well informed about emerging innovations, material developments and regulations means we can integrate them in designs. We must understand and recognise what innovations are appropriate, feasible, safe, and effective.
Priorities and focus are likely to continue to shift as regulation creates more opportunity for embodied carbon to come to the fore. IStructE and the RIBA, for example, with nine other major built environment organisations, have called on UK political party leaders to make a manifesto commitment to regulate embodied carbon. California and the EU already have regulations in place.
In the context of embodied carbon, the engineer-architect relationship plays the primary role through immediate reductions in embodied carbon and by creating a sustainable legacy through their designs.
Willingness to explore and co-create designs is essential to deliver balanced carbon reduction along with quality of space, place and safety and a highly functional building. It requires the whole industry, especially contractor and client, to be equally invested.
Together, architects and engineers are well placed to lead the charge towards faster reduction of carbon emissions in the construction industry.
Tanya de Hoog is president of the Institution of Structural Engineers