Bentonite clay, a common component of the expansive soils found throughout Colorado’s Front Range, poses significant risks to residential and commercial foundations due to its high volatility. Its impact is primarily driven by a seasonal moisture cycle that creates constant physical stress on structures.

Key effects of bentonite clay on foundations include:

• Heave: When bentonite clay absorbs water, it swells dramatically. This expansion creates upward pressure that can lift a foundation, a phenomenon known as heave.
• Settlement: During dry periods, the clay shrinks and loses volume. This creates voids beneath the foundation, causing the structure to settle or sink into the gaps.
• Structural Damage: This continuous cycle of swelling and shrinking results in differential movement. This movement typically manifests as visible damage, including cracking walls, uneven floors, and doors that stick or fail to close properly.
• Lateral Pressure: Beyond vertical movement, these soils can exert lateral earth pressure against foundation and retaining walls, often leading to inward bowing or structural instability.

To address these aggressive soil conditions, Colorado experts typically recommend deep foundation systems like helical piers. These systems bypass the active clay layer to anchor the structure in stable, load-bearing soil strata deep underground.