Ground & Water’s client wanted to extend and redevelop an existing building into residential apartments. The extension would comprise the construction of a new three-storey building at the northern end of the site, connected by an under-croft supported by columns. A new lift core would be constructed next to the existing building, with a raft foundation underpinning the existing foundations. The foundation supporting the under-croft was unevenly loaded, so a stepped-raft foundation was adopted to support the additional load on one side.
Previous Phase 1 and Phase 2 site investigations, undertaken by others, could not get the proposed loads to match the underlying soil conditions and the client was facing expensive underpinning or piling.