Underpinning is a foundation repair method used to strengthen or stabilise an existing foundation. It may be required when part of a building's foundation has moved, weakened or is no longer providing adequate support.

Possible signs include significant cracks in walls or brickwork, uneven floors, doors or windows becoming difficult to operate, and movement within sections of the building. These symptoms do not automatically mean underpinning is required, so the cause should first be properly assessed.

The appropriate underpinning method depends on the building, foundation condition, soil conditions and cause of movement. The property should be assessed before determining the most appropriate repair approach.

Underpinning is intended to strengthen and stabilise affected foundations. However, every property and ground condition is different, so the expected outcome depends on identifying the cause of the movement and selecting an appropriate solution.

The timeframe depends on the extent of foundation movement, the areas requiring work, site accessibility and the underpinning method required. A more accurate timeframe can be provided after inspection.

Some underpinning projects may require assessment or documentation from a suitably qualified structural engineer. Where engineering input is required, this can be discussed as part of assessing the project.