What is Foundation Repair?
Foundation repair is, at a minimum, stabilizing the foundation so it will not continue to settle further. In some situations, it can be lifted to its original starting point, but the chances of that happening typically lessen with time.
A foundation is only as good as the soil that it stands on. Foundation settlement problems are most often caused by weak soil, or soil that was not properly compacted. As the soil changes, it becomes less able to support the weight of the house, so the house responds by developing cracks as it settles. Repairing settlement problems like this is accomplished by transferring the weight of the structure to more stable, stronger soil using helical piers or resistance piers. This process is also called underpinning.
- Water is the dynamic that causes the soil to change. Too much water can cause some soils to swell. In other soils, too much water can cause the particles to consolidate and settle. On the other extreme, drought conditions can cause soil to get very dry and shrink. These changes in the soil moisture content causes the house to settle with the heavier portions of the home settling more then the other areas, as the soil below it shrinks and swells.
- Weak soil can be close to the surface or there can be a layer of it several feet below. The surface water fluctuations and weather changes usually affect the upper 15 feet of soil. The only way to deal with this problem is to support the footing using the firm soil that is not affected by surface conditions, which is typically 15 to 20 feet below the surface. This is done by using helical or resistance piers, which are driven into the ground with hydraulic equipment. A skilled contractor should be able to lift the structure 70% of the time, so inquire as to what his lift rate is on prior installations.