Winner: Sustainable renovation of the year 2025. Squire and Partners has retrofitted and extended Space House, a rare Grade-II listed brutalist building originally designed by Seifert in 1968 in London, England.

A symbol of the 1960s commercial property boom, Space House is a Grade-II listed brutalist building comprised of a distinctive cylindrical tower, rectilinear block and connecting bridge.

Originally designed by Richard Seifert and Partners in 1968, Squire and Partners' retrofit removes layers of subsequent interventions to celebrate the existing architecture, while accommodating 255,000 square feet of intelligently designed workspace.

"90 per cent of the original structure has been retained, saving an estimated 10,000 tonnes of carbon emissions," said Squire and Partners.

A rooftop extension has been added to the Tower, reinstating Seifert's intention for a crisp roofline silhouette and providing two additional floors of workspace.

Judge comments: "At a time when many of the UK's modernist buildings are being demolished, Space House proves that maintaining these iconic structures doesn't have to mean sacrificing liveability or operational efficiency."

"Squire and Partners retained an impressive 90 per cent of the original structure, providing a humble yet transformational overhaul that prioritises sensitivity over ego."

Studio: Squire and Partners
Project: Space House
Credits: Seaforth Land, QuadReal, Pell Frischmann, Atelier Ten, Donald Insall Associates, Gustafson Porter + Bowman, Gardiner & Theobald, Gerald Eve, Avison Young, BAM, Erith and Paye Stonework & Restoration