This mixed-use development is situated in the heart of Knightsbridge, London SW1. The existing Grade II listed building has been extensively redeveloped featuring the retention of the original 120m long facade dating from 1905, which forms part of the local conservation area, with a complete rebuild and isolation of the building behind.
The project includes new and refurbished spaces to provide 15 high-end residential apartments over the first to fifth floor, 3,400 m2 retail on the ground floor, and 3,100 m2 office space on the first and second floors. With proven expertise in designing for both high-end residential and historic buildings to achieve high standards of acoustic performance, Sandy Brown were commissioned to provide advice on the design and fit-out of all acoustic aspects throughout the development, from shell and core through fit-out and commissioning.
A key aspect of the design was building vibration isolation. The proximity of the Piccadilly Line and the Knightsbridge Road generated noise levels that would be undesirable within the building. The decision was taken to isolate the new internal structure and connect back to the retained facade with specialist isolation bearings. The isolation line turns horizontally at the first-floor slab, then extends down vertically to capture the lift shaft into the basement. This isolation was carefully coordinated into the internal sound insulation design, which needed to accommodate a significant gap between the retained facade and isolated structure.
The development also incorporated multiple construction types and complex interfaces in relation to both historic and new-build elements. We undertook extensive benchmark testing and site inspections to quantify and understand the performance of the retained building elements. This allowed specific solutions and detailing to be developed for the different areas of the site. With high levels of road traffic noise, the original single glazed windows were retained, with secondary glazing installed to all historic areas to control external noise ingress.