A slab foundation’s purpose is to provide weight-bearing support for a building. The slab foundation, constructed of concrete, fits over footings also made of concrete. Typically, the footings anchor to the slab via reinforced steel bars (rebar). The soil under the foundation also should be leveled and prepared to help create a moisture barrier between the ground and the home. Sometimes slab foundation problems derive from improper slab construction, soil movement under the slab as well as sewage and water leaks under the slab.
Water leaks under slab foundations unfortunately occur. Often the leak is a result of cracks in the pipes that run under the slab, providing water into the home. If your home has hard water, over time the mineral buildup from the water traveling through the pipes can cause small cracks and leakage.
Other issues that may cause pipe cracks include tree root intrusions and the expansion and contraction of soils, especially the expansive clay soils such as those found in areas of Texas, Colorado, Alabama and other many other states. Any area with expansive clay soils may experience issues. Pipes, particularly plastic pipes that nestle under slab foundations suffer stress due to the expansion and contraction of the soil. The result can be cracks in the pipe and water leaks under the slab.
Improper drainage of water away from the house can contribute to water under the slab foundation as well. Lack of gutters or disconnected downspouts allow excessive water to dump onto the soil nearest the foundation during heavy rains. Without proper drainage, the soil becomes over-saturated. Low soil areas around the foundation and landscaped beds that do not slope away from the home also add to drainage issues.
Any leaks under a slab foundation can cause excessive moisture to seep into the home. It also may cause the affected area to heave, pushing the soil upward and affecting the slab’s stability. House foundation problems once begun often lead to additional problems. Slab foundation problems can be related directly to cracks in sheetrock, uneven floors and can even lead to a decrease in the home’s value. A water leak under a slab foundation needs to be evaluated by a qualified professional.