Underpinning and Geotechnical Repairs
Whether a house has a raised foundation or a slab foundation, the underlying soils that the footings rest on can move, causing damage to the house and it’s foundation system. Natural soil that a house is constructed on can consist of a range of soil types. Typically, the natural soil that moves the most is expansive clay soils. When clay gets wet, it expands. When it dries out, it contracts. So, in the winter, clay soil typically gets wet and expands, which does not necessarily lift the house, but can cause the soil to lift around the footings, in an action called pumping. As long as the underlying soil stays wet, the footings will be relatively stable. In the summer, however, the soil dries out; typically more on the South side of the house, and this can affect the footings, causing them to settle. The soil under the middle of the house can take longer to dry, causing a relative heaving or higher area at the middle of the house.