What Is Foundation Heave and What Causes It?

Foundation heave happens when the soil under your slab takes on water and swells. The upward pressure lifts part of the foundation, while the rest stays put. That uneven movement creates stress on the concrete, which often shows up as cracks in your floors, walls, or ceiling.

The most common cause is expansive clay soil, which can swell significantly when wet. In a humid subtropical climate, heavy rains and a Gulf hurricane season can saturate the ground. Poor drainage around your home, a leaking pipe, or an overflowing AC drain line can also add moisture to the soil.

Start by checking for plumbing leaks under your slab or in the walls. A hidden leak can saturate the soil over time. Also inspect your gutters and downspouts to make sure water is directed away from the foundation.

Your yard's grading matters too. If the ground slopes toward your home, rainwater will pool near the foundation. A clogged AC drain line can overflow and soak the soil next to the slab. Fixing these sources helps stop the heave from getting worse.

• Plumbing leaks under the slab
• Clogged or overflowing AC drain lines
• Gutters that dump water near the foundation
• Downspouts pointing toward the house
• Yard grading that slopes inward
• Sprinklers that spray onto the foundation

Foundation heave is not a simple DIY fix. The pros can assess the extent of the movement and identify the moisture source. They usually bring specialized equipment to measure the slab and check the soil conditions.

If water damage has already affected your drywall, flooring, or ceilings, you may need additional help. The pros can handle the cleanup and repairs. For a thorough evaluation, consider a water damage inspection to understand the full scope of the problem.