Delvendahl Martin Architects undertook a comprehensive refurbishment of the former Credit Lyonais headquarters building located at 30 Cannon Street in the City of London. The existing office building occupies a prominent wedge-shaped site near St. Paul’s Cathedral which was designed for the London headquarters of Credit Lyonnais by Whinney Son & Austen Hall (later Whinney McKay-Lewis Partnership) in 1977. It is the first building in the UK to use glass reinforced concrete (GRC) as a façade material, and has become a point of reference for manufacturers and façade specialists. Moreover, it was added to the National Heritage List in 2015 as part of a group of 14 post-war office buildings, in recognition to its architectural value and contribution to the built environment.

Delvendahl Martin were appointed in 2013 to carry out a feasibility study to determine the re-development potential of the building in response to current market and environmental demands, with the main aim of prolonging its life-span. The study led to a project that included the upgrade and re-location of the existing building services, the extension of the 5th floor and a comprehensive refurbishment of the 3rd floor, main entrance lobby, and re-glazing of all main façades to improve the performance of the envelope. A key aspect of the plant relocation was the opportunity to create a new roof top terrace in line with the Council’s guidance advocating green roofs, and following the height constrains imposed by the London View Management Framework and the St’ Paul’s Heights Policy Area. All this was achieved whilst aiming to preserve the architectural integrity of the building, which required extensive research to identify the original elements, modifications and later additions. This helped to establish three main design principles that new elements had to adhere to: geometry, materiality and colour. After securing planning and listed building consents in early 2015, the main works reached practical completion in September 2016.