One Exchange Square reimagines a 1980s office building and demonstrates how novel methods can be used to expand commercial floor space on a large-scale cut & carve project whilst minimising carbon impact. The whole building has been redesigned to deliver healthier working environments with roof terraces, interior planting and a diversity of uses contributing to a revitalised whole.

The project delivers a substantial 11-storey, 7.5m extension above London Liverpool Street Station without foundation strengthening, avoiding the significant embodied carbon associated with new basements and deep piling. An exoskeletal transfer truss and hanger system redistributes loads back to the retained structure, enabling 94% structural retention by volume, prioritising flexibility and material efficiency. Preloading the structure and removing it as the facade was installed minimises movement of the cladding system.