Your house is founded over highly plastic clay soils. The highly plastic clay soils are characterized as very expansive or possessing high shrink-swell potential. Simply, these expansive soils have the ability to shrink and swell when becoming dry and swell to a large volume when wet. Seasonal moisture variations, vegetation, and precipitation pattern directly affect this sponge-like behavior. In Texas, the clay typically swells in the winter and spring (wet months) and shrinks in the summer and fall (dry months).