Frost heave is one of the most common — and most misunderstood — foundation issues we encounter during inspections in the Mat-Su Valley and Anchorage area. Here's what it is, why it happens, and what warning signs to look for.

WHAT IS FROST HEAVE?

When water in the soil freezes, it expands. That expansion pushes upward against anything in its path — including your foundation, driveway, sidewalks, and deck posts. The problem isn't the freezing itself; it's the uneven movement that happens when different parts of the soil freeze and thaw at different rates.

WHY ALASKA IS PARTICULARLY VULNERABLE

Our soil composition varies widely across the region, and moisture levels can shift significantly with snowmelt and rainfall. Homes built on clay-heavy or silt-heavy soils are especially prone to heaving. Inadequate drainage, poor grading, or a foundation that doesn't extend below the frost line can all make the problem worse.

WARNING SIGNS TO WATCH FOR

Cracks in foundation walls or concrete slabs that appear to grow or shift seasonally are a red flag. Doors and windows that stick in winter but loosen in summer often point to structural movement. Uneven floors, gaps between walls and ceilings, and visible gaps under sill plates are also common indicators.

WHAT CAN BE DONE?

Drainage improvements are often the first line of defense. Proper grading that directs water away from the home, along with functional gutters and downspout extensions, can reduce the moisture available to cause problems. In more serious cases, a structural engineer may need to assess the foundation.

During every Ridgeline inspection, we evaluate foundation condition with Alaska's freeze-thaw cycle in mind. If we see signs of movement, we document them thoroughly so you have a clear picture before you buy.