A traditional method of underpinning; this technique involves digging below the existing foundation which is failing, then casting a new foundation underneath to support the original structure in a pre-designed sequence.
Diameter: built to design.
Ground Condition: clay, coarse soil.
Excavations do not require machinery.
Allows the ground condition to be reassessed.
The new foundation forms a barrier to protect the older structure.
Retains the structure.
Spreads the load to ease stress on weak footings.
The foundations are excavated along the outside wall. Trenches are dug out below the existing footings in a predetermined sequence of intervals. The size and depth of each trench is calculated by a structural engineer.
The new trenches are checked for stability and any potential heave that can be caused by tree roots or ground moisture.
Concrete is placed in the new trenches leaving a narrow gap between the cast concrete and the old foundation. Once the concrete has cured the gap is dry packed to redistribute the load of the structure.