30 Cannon Street – London, UK

2015 – Construction

30 Cannon Street is an office building that occupies a prominent wedge-shaped site near St Paul’s Cathedral in the City of London, and was designed in 1977 for the London headquarters of Crédit Lyonnais by Whinney Son & Austen Hall (later Whinney McKay-Lewis Partnership). Delvendahl Martin were appointed to undertake a comprehensive refurbishment that included the addition of a new roof terrace.

In 2013 Delvendahl Martin carried 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 lifespan. This 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. 30 Cannon Street was the first building in the UK to use glass reinforced concrete (GRC) as a façade material, and as such, has become a point of reference for manufacturers and façade specialists.  A key aspect of our refurbishment was the opportunity to create a new roof top terrace in line with the Council’s guidance advocating green roofs, and following the height constraints 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 the new elements adhered to: geometry, materiality and colour. 

After securing planning and listed building consents in early 2015, the main works reached practical completion in September 2016. Moreover, 30 Cannon Street was added to the National Heritage List for England in 2015 as part of a group of 14 post-war office buildings, in recognition of its architectural value and contribution to the built environment.

Project Team

Max Martin

Stephanie Thum-Bonanno

Max Gelibter

Structural Engineer


Services Engineer

Hoare Lea

Main Contractor


Building Control



Forbes Massie


Tim Crocker