Why are expansive clay soils a problem in Texas?
TexasReviewed October 2026
Expansive clays swell when wet and shrink when dry, and that movement lifts and drops whatever sits on them. The Texas Department of Licensing and Regulation calls shrink-swell soils a very common cause of foundation problems: high moisture makes the soil heave and lift a building, and low moisture makes it shrink and settle. Dallas County Master Gardeners, an AgriLife Extension program, note that the black clay common in North Texas behaves this way, so keeping soil moisture steady around a foundation is the goal. For a light home on piers, uneven movement shows up as doors that stick, out-of-level floors and stressed utility connections. Good drainage, consistent moisture and a foundation designed for the soil are the main defenses.
Check your local rule. This varies by state, county or city. Your permitting office has the final word; the official lookup pages below show you who that is.