Twenty Berkeley Square

Tags: offices, retail, refurbishment

  • Client: Berkeley Estate Asset Management
  • Architect: Barr Gazetas
  • Photography: Jack Hobhouse
  • Completion: 2024
  • Value: £10m
  • Size: 22,000ft²
  • Expertise: Structures, Civils
Twenty Berkeley Square - Webb Yates Engineers
Twenty Berkeley Square - Webb Yates Engineers
Twenty Berkeley Square - Webb Yates Engineers
Twenty Berkeley Square - Webb Yates Engineers

Designed with Barr Gazetas, the project involves the refurbishment and extension of a 1930s office block sat on the north east corner of Berkeley Square, between Bruton Place and Bruton Street. Our team provided the structural and civil engineering designs for the development, which is now one of the greenest office buildings in Mayfair with a BREEAM ‘Outstanding’ rating. 
The retrofit of the nine-storey structure has created 22,000ft² of renewed spaces, including offices, restaurant, and private and communal roof terraces overlooking the square. Original features, including the terrazzo staircase and the façade, have been repaired and restored. 
Detailed structural surveys of the existing building were completed, allowing for light structural interventions in the superstructure to support the renovation, as well as adjustments and extensions to lift and stair cores, and a lightweight single storey roof extension. 

At basement level, walls and other supporting structures have been moved or adjusted to allow for new drainage to service above. As part of an early works package, ahead of the main refurbishment, a large extension of existing vaults was undertaken to house a new substation. The existing below ground drainage system was repurposed for the building’s future use, including drainage provision for a firefighting lift, carefully coordinated with the existing and new foundations of the building.