Foundations in areas with highly expansive soils are vulnerable to shifting and settlement. Although foundation settlement can occur suddenly, it is often very predictable. The key to understanding foundation problems in the greater Houston area is to understand the expansive nature and properties of the soils we build on.
The expansive soil on your property reacts quickly to moisture. This means the soil will shrink and lose volume when dehydrated and alternatively, these soils will expand in size and volume when saturated. Houses are very heavy and tend to settle when the surrounding soil becomes dry. A saturated, expanding soil can exert several tons of pressure per square foot on a foundation.
Healthy foundations require uniform moisture content in the surrounding soils. This condition is not consistently found in nature and must be actively cultivated by homeowners. This includes providing positive grading, managing foliage, and providing adequate moisture in times of drought.
Too much water can be just as destructive to a foundation as not enough water. To prevent foundation problems, it is important to provide proper drainage of storm waters. This includes positive grading along the foundation perimeter, so water is directed away from the home. Water should never be allowed to sit or collect near a foundation. If grading and drainage issues were noted in your inspection report, strongly consider improvements such as installing rain gutters and/or surface drainage systems.
Not enough water will cause soil to shrink and foundations to settle. If you notice soils beginning to crack or pull away from a foundation, or if rainfall has been sparce, consider hydrating the soils surrounding your foundation. This is most efficiently accomplished by irrigation systems, but regular use of dripper hoses can also be effective.
When the moisture content of the soils under your foundation are not uniform, foundation movement is a possibility. Indicators of foundation movement may include but is not limited to cracks in the exterior brick veneer, cracks in interior walls, doors or windows that stick or become difficult to operate, cracks in tile flooring or vaulted ceilings, and framing issues such as rafters that pull away from each other in the attic.
We recommend contacting professionals, prior to the expiration of any option periods or contractual deadlines, if any of these indicators are documented in your inspection report. The information that can be obtained in this manner may strengthen your negotiating ability or better inform you when deciding to purchase this property. If no indication of foundation movement was observed at the time ofinspection, please u nderstand that soil conditions change with time and changes in foundation performance can occur suddenly. If you are interested in having the foundation inspected on regular time intervals, contact our office for further information and assistance.