A leading example of material reuse, the project is one of the first to reuse steel salvaged directly from a demolition site, reducing embodied carbon and aiding growth of the second-hand materials market in the construction industry.

Grosvenor’s UK property business is working on an innovative framework to reduce the embodied carbon of projects through circular design strategies.  

A leading example of material reuse, Holbein Gardens is one the first projects in the UK to reuse structural steelwork salvaged directly from a demolition site. The project is Grosvenor’s first net zero scheme, setting a new benchmark for sustainable workplaces through the transformation of a 1980s office building.

The project addresses and resolves complex issues currently surrounding the reuse of structural steel such as the cost of salvaging, programme constraints and the availability of reusable stock. 

The salvage and reuse of the steel has been enabled by working alongside structural engineers Heyne Tillett Steel and steel stockists Cleveland Steel.

Tom White, Project Manager, Grosvenor, commented: “By ensuring environmental performance was central to the Holbein Gardens brief from day one, the team have been able to trial an array of new construction methods and materials. 

“The re-use of salvaged steel is just one example of how we have sought to drive a reduction in embodied carbon. By continuing to work closely with our suppliers, the lessons learnt will be invaluable to our future pipeline and journey to achieving net zero carbon by 2030.”

Located in Belgravia, the existing 1980s office building is undergoing a 25% area uplift and upward extension, requiring approximately 70 tonnes of steelwork. Through research and structural investigations, 9 tonnes of existing steel were identified and reclaimed from a nearby demolition site within Grosvenor’s portfolio. This has been combined with additional 15 tonnes of reused steelwork sourced by Cleveland Steel and refabricated to form the building’s rooftop extension.

Repurposing structural steel in this way delivers significant environmental benefits, reducing the overall embodied carbon of each steel member by a factor of eight compared with new steel. When split across the total area, the reuse of existing steel beams and columns has saved around 60 tonnes of embodied carbon. This has lowered the overall embodied carbon for the building to 267.9kgCO2e/m², of which 67.5kgCO2e/m² is attributed to the structure. 

Programme implications prevented steelwork from the existing building being reused at Holbein Gardens, but this has been salvaged for use on other Grosvenor projects, providing further circular economy benefits.

Tom Steel, HTS Director said: “It’s really exciting that we have managed to get the repurposing of steel to work on this project. The practical challenges associated with identification, extraction and refabrication often put clients off but we have worked through these proving it’s doable and can bring significant embodied carbon benefits. The opportunities for use of repurposed steel are massive and I can see this being rolled out on many projects in the coming years.”

While reducing embodied carbon, the use of salvaged steel at Holbein Gardens has provided an evidence-based approach to expand the second-hand materials market within the construction industry. 

Working closely with Cleveland Steel, a leading fabricator within the reuse of steel market, the reclaimed material has undergone a unique assessment process to confirm surface condition, coating and end preps to understand the existing condition. Coupled with structural material testing, this process reveals the material’s grade, strength and dimensions to enable the steelwork to be designated the same quality as newly fabricated steelwork. 

Roy Fishwick, Cleveland Steel added: “CST are delighted to be involved in this project promoting steel reuse and circular economy. It has allowed us to find solutions to new challenges posed by this activity. It has been refreshing to be a part of a project where everyone from the client down believes in the principles and benefits of reuse. As our inventory of reused materials grow then we should be able to assist more and more projects with their carbon targets”

With the project now on site, the process has delivered a proven framework justifying existing steelwork for reuse as well as demonstrating its development value as a second-hand material.