Synopsis
A 1960s office building in central London has been reinvented as the new headquarters of The Institution of Structural Engineers. Structural interventions were focused in specific areas to control costs, limit material use along with associated embodied energy, and shorten the construction period. A large opening was formed in the first floor to create a new atrium linking the members' areas at ground and first floors. The precast concrete planks forming the first floor were strengthened using carbon-fibre reinforcement to maintain diaphragm action around the atrium and to strengthen the library floor for book storage. A horizontal-cantilever stair was installed in the atrium. The stair is a minimalist reinterpretation of traditional cantilevered stone stairs and creates a structural engineering feature.