The project was located in the Mayfair Conservation Area and was adjacent to the Grade II* listed James Wyatt Building at No. 9 Conduit Street.
The scheme involved the demolition of the existing buildings at 10 and 11 Conduit Street and the construction of a new seven storey building, with a single level basement, to provide retail space on the ground floor and open plan office space on the upper floors.
Top-down methodology was employed so that the superstructure could be constructed concurrently with the excavation and formation of the basement. Basement excavation and piling works needed to be carried out sensitively to ensure no impact on the adjacent listed buildings and the Victoria Underground line running beneath part of the site.
We installed a king post wall (involved plunge posts in permanent bearing piles) to support the ground floor slab. The site was located over the London Underground Victoria Line Pile Exclusion Zone, so sections of lining wall were installed early to act as a deep beam to support the ground floor slab. Reinforced concrete underpins were also installed to the perimeter to facilitate the construction of a crane base below the formation of the permanent works basement level lift pit.
The building featured a unique and stunning curved feature façade clad in Whitbed Portland Stone over the full height of the building. The design resembled overlapping wings flowing from the ground floor up.
Sustainability was a central to the design of the building in order to achieve a BREEAM Excellent rating. The site was also within a city-wide Air Quality Management Area, so it was vital that emissions were kept to a minimum for the client to deliver against GLA air quality targets.
