Twenty Grosvenor Square is a redevelopment of the former European Headquarters of the US Navy in the heart of historic Mayfair. Client Finchatton partnered with Four Seasons Hotels & Resorts to offer the first standalone residential project which benefits from Four Season’s world-leading hotel services. The design revives a historically significant building to establish a new contemporary residential address befitting its prestigious location.
The 250,000 sqft development comprises 37 apartments and penthouses with resident amenities, including a 25m swimming pool, spa, cinema, garden library, wine cellar and business suite. Nine different apartment types include 1-5 bedrooms, duplex, triplex, and three variations of penthouse, with one occupying the whole eighth floor with private roof terraces. The removal of an existing central bay to North Audley Street, within two existing bookends, clarified the orientation of the building and established an identity with a contemporary setback elevation featuring a porte-cochere entrance.
Crafting traditional materials of brick, glass, stone and metal with modern technologies such as CNC machining, waterjet cutting and laser cutting has created an intricately detailed elevation drawn from the rich history of the area. Bespoke façade details include contemporary pilasters, fluted stone, projecting bay windows, linear balconies and ornate patterned metalwork. The existing elevation to Grosvenor Square has been refurbished and layouts amended to establish garden views from reception rooms and master bedrooms. A new slate-clad stepped mansard enhances the penthouse levels, and improves the aspect across Grosvenor Square and the surrounding Mayfair roofscape.