We were approached by a local loss adjustor to design a scheme to stabilize the rear kitchen, the structure had moved because of past leaking drains which had been subsequently repaired. As the main drain run was positioned 400mm parallel to the side wall, only an internal underpinning scheme could be achieved. Because of the soft nature of the subsoil to a depth of 1.0m, a piled underpin slab was the most cost effective solution.
This would take the form a 450mm wide by 300mm deep reinforced concrete needles being cast into the walls below external ground level and supported on 150mm diameter steel cased bottom driven piles. A 200mm deep reinforced slab would then be cast over the needles and tied into them to form the counterbalance required in the design carried out in-house by our engineer. Work completed within 5 days.