A new eight-storey commercial building at 30 Duke Street St James’s is under construction in London’s West End, replacing 50 Jermyn Street and French Railways House (Piccadilly frontage) with a modern office-and-retail scheme designed around high levels of structural reuse. The development, led by GPE with Make Architects, is being delivered by Mace, with structural engineering by Elliott Wood and steelwork by William Hare.

The project’s key technical milestone is its 559t steel frame, of which approximately 77% is reclaimed. The largest single source is City Place House, another GPE London asset, providing 375t, equal to 67% of all steel used on the scheme. A further 3t of steel, previously part of a plant deck, was salvaged from the demolition of French Railways House. Additional reclaimed sections were supplied from stock held by Cleveland Steel and European Metal Recycling (EMR), supplemented by 54t of new steel where required for performance and detailing.

Mace reports that the reclaimed-steel strategy has delivered an embodied carbon saving of 744t CO₂e, supported by offsite fabrication and reduced site operations. Reuse, however, required intensive refabrication: reclaimed beams were often too long and had to be cut to suit the new grid, while some columns were spliced (up to three segments) to achieve full storey heights. Previously solid beams were also reworked into cellular members, with bespoke openings cut to allow building services to pass through the structural zone.

The structural concept uses a concrete core offset along the western party wall, allowing steel beams spanning up to 13m to radiate to the north, east and south elevations, creating column-free office floorplates. Floors are formed as composite slabs using metal decking and a concrete topping. The retained single-storey basement and a double-height ground floor accommodate retail and reception, with offices above and terraces on the top three levels. Completion is expected mid-2026, targeting BREEAM Outstanding and WELL Platinum.