That small crack in your foundation, brick wall or concrete floor has deeper consequences and is the subject of major economic concern in the U.S. More than one person in five is, or will be, affected economically by structural damage. By comparison, fewer than one in ten is affected by flood or earthquake. Homes built on shrinking or swelling soils have up to a 60 percent chance of damage from this little known, and even less understood, natural occurrence.
Structural damage ranks as the second most-likely natural cause of economic loss (insect damage is first). Estimates prepared by the Federal Housing Administration approach $20 billion annually.
What can a homeowner do?
Trace visible signs of settling or structural movement to its source. Here are a few signs to watch for:
•Doors and windows open and shut with difficulty.
•Caulking cracks and pulls loose around windows and doors.
•Concrete floors crack, tilt and move.
The problem should be tackled while in its early stages. Once the structural unity of the building is broken, continued movement can affect more of the structure.
Many, methods are used to stabilize a building structure that has failed. Underpinning the foundation is the most effective. The system of shallow excavation and pouring concrete pads and piers is effective, but can fail in the long term. This method almost never reaches the depth necessary to connect with a strata of sufficient bearing quality. In addition, traditional methods can be costly in terms of time and the effect of disturbance of lawns, landscaping and other areas.
The most effective method is to underpin the structure with steel piering, which is
driven to a sufficient depth to support the calculated load. This remedy tends to be permanent and, on some applications, can be adjusted later if necessary. This system also can be installed more quickly, and with less site disturbance.