The contractor is carrying out the major refurbishment and restoration of the Grade II* listed 66 Portland Place building in Westminster, with completion due in September 2027.

The Portland Place scheme will act as a pilot project for the Net Zero Carbon Building Standard and involves a major upgrade of the building fabric and services.

Gilbert-Ash is stripping out and replacing ageing building services as well as carrying out improvements to the external envelope to boost energy efficiency and tackle water ingress.

The project will also improve accessibility throughout the 1930s headquarters and remodel public areas to give greater prominence to the café and RIBA shop.

A new fully accessible entrance will be created on Weymouth Street alongside new exhibition and events spaces as part of RIBA’s wider House of Architecture programme.

Purcell is architect for the delivery phase, taking forward the concept developed by Benedetti Architects.

Gardiner & Theobald is project manager, Jackson Coles is quantity surveyor, Eckersley O’Callaghan is structural engineer and Harley Haddow is services engineer.