What can excessive moisture in expansive soil cause?

Excessive moisture in expansive soil can lead to foundation settlement because expansive soils are known to change volume significantly with variations in moisture content. When these soils become too saturated, they expand, creating pressure against foundations and structures. Conversely, as the moisture content decreases, the soil shrinks, leading to potential voids beneath the foundation. This swelling and shrinking cycle can cause movement in the foundation, resulting in settlement or differential settlement. Such movement can compromise the integrity of the structure over time, leading to further structural issues, like cracking walls or uneven floors.

While soil erosion, pavement cracking, and increased soil density can be associated with various soil and moisture conditions, they do not directly result from the moisture effects in expansive soils in the context of foundation stability. Thus, the phenomenon of foundation settlement is the most relevant consequence of excessive moisture in expansive soil.