- Never allow the soil around and below the house to become dry during extended dry periods. Highly expansive clay soil will shrink in volume and allow the foundation to settle downward. The foundation will experience "differential settlement" which is detrimental to the building structure if the soil at the perimeter foundation dries before the soil under the floors. The soil usually dries slowly under the floors because its moisture is trapped by the floor of the building.
- Never apply water directly into the gap that opens between the concrete slab and the soil during extended dry periods. Water flowing under the concrete grade beams that make up the support the building will dissolve the clay in the soil below the beams and carry it away into the cracks that form in the yard as the soil dries. Soil carried away in this manner is lost and so is the height that it contributed to the elevation of the foundation.
- Never allow the surface of the soil immediately adjacent to a concrete slab or grade beam or the piers that support a building to acquire a slope toward the building. The surface of the soil should be carefully graded to slope away from the building at a rate of more than 1" per foot for a distance of three to four feet. An example of creating undesirable perimeter drainage is where a dog digs a cooling pit at the edge of a foundation.
- Never repair damaged areas inside your house until you have found the cause. You should not cover up the symptoms of foundation settlement until you have corrected the problem. This will save both time and money on repeated repairs.
