The primary difference between foundation sinking (settlement) and foundation heaving is the direction of movement and the underlying cause related to soil behavior.

Foundation Settlement (Sinking) Settlement is the downward movement of a structure. It occurs when the soil beneath the foundation compresses or consolidates. Common causes include:

• Poor soil compaction during original construction.
• Significant fluctuations in water content (drought vs. excessive rain).
• Shrinking of expansive clay soils during dry periods.

Foundation Heaving (Rising) Heaving is the upward displacement of a foundation. This is typically triggered by expansive clay soils (common in Colorado) that absorb moisture from rain, snowmelt, or plumbing leaks. As the soil volume increases, it creates vertical pressure that pushes the foundation upward.

Visual Differences While both issues cause cracks and sticking doors, they often leave distinct patterns:

• Settlement: Often produces diagonal or "stair-step" cracks in masonry that are wider at the top. Doors and windows typically sag or develop gaps at the top corners.
• Heaving: Often produces horizontal or vertical cracks in concrete floors. Cracks may be wider at the bottom, and doors often jam at the top rather than sagging.

Because repair strategies differ fundamentally—settlement often requires deep underpinning like steel piers, while heaving requires moisture control and drainage—a professional geotechnical evaluation is essential.