Project Description

Abbey Pynford’s Basement Engineering Division has successfully completed a demanding project upon London’s hereditary Grosvenor Estate. Following discovery of 120m3 of existing concrete beneath the Mews property, the client’s construction programme was at risk of considerable extension.

Abbey Pynford’s innovative temporary works scheme coupled with close working with the client and their engineers; enabled the unforeseeable obstructions to be overcome, the programme accelerated to mitigate the effects of the obstructions and the project completed 3 weeks ahead of schedule.

Abbey Pynford constructed a 4.1m deep top down basement using innovative temporary works techniques. The front existing vaults were also adapted into an enlarged plant room providing the client with a greater living space.

Abbey Pynford used Kryton concrete additive to waterproof the basement.

Construction Phase Highlights

After separating the existing foundations from the party walls, the existing reinforced concrete slab was broken out and temporary piles installed to prop the existing ground and lower ground floor slabs before the until load bearing walls were constructed. The bespoke piles were installed using one of Abbey Pynford’s restricted access piling rigs. The piles were designed for fast and efficient removal at the end of the project to minimise the risk to Health and Safety as well as the follow on programme.

Once the stability of the existing property was secured through the installation of the temporary works, Abbey Pynford’s specialist underpinning operatives were mobilised to install 30 no. 4m deep underpinning bases to 3no. Party walls around the basement.

The underpinning bases were installed without any movement of the existing walls and with Kryton water resistant additives.

Upon completion of the perimeter underpinning bases, the new lower ground floor basement top slab was constructed. This propped the underpinning and allowed the client to begin works above whilst the basement was excavated to depth below.

Once excavated, Abbey Pynford worked within the basement shell to complete the project with a basement slab and internal structural walls.