Why will a precast concrete piling system fail in clay soil?
The pressed concrete pier underpinning system often rests upon a water sensitive layer of clay. In the presence of water, clay particles expand, slip, and slide. The most common problem with the reliance upon stiff soil in the pressed concrete pier system occurs when the soil moisture content increases, such as during a rainy season, with a concrete pier driven shallow. Stiff clay becomes soft. The clay loses the ability to support the underpinning. Furthermore, surface friction drops as moisture increases. The weight of the house pushes down on the pressed concrete pier, and it sinks. To correct this problem, the foundation repair contractor may add steel shims between the concrete piling and the house. But that does not guarantee against further sinking of the pressed concrete pier. Why will a steel pier system not fail in the same clay soils as that of a pressed concrete foundation repair system? Quite simply, the steel pier system usually rests upon a solid, water insensitive surfa
