Sinking Foundation Repair

What Causes a Sinking Foundation

Crawl space support pillars are sometimes built on soil that isn't strong enough to carry the weight of the home, and over time those supports sink into the soil, pulling the floor above down with them. In other cases, a home's support beams were spaced too far apart at construction, and the floor sags in the spans between supports. Long-term water intrusion and moisture under the home weaken the soil supporting those piers and rot structural wood, while foundation walls themselves can settle or buckle under pressure from expansive soil outside the home.

Signs to Watch For

• Stair-step cracks in exterior walls
• Sagging or noticeably uneven floors
• Doors and windows that stick or won't latch properly
• New or widening cracks in interior walls
• Visible gaps or leaning at crawl space support piers
• Moisture or standing water in the crawl space

Is It the Foundation, or What's Under the House?

These get called the same thing and they are two different jobs with very different costs, so it is the first thing the inspection settles.

• Interior settlement. The crawl space support columns are sinking into the soil they were built on, taking the floor above with them. The perimeter foundation is fine. This is the more common of the two here, and the fix is support jacks and structural repair — a considerably smaller job.
• Perimeter foundation settlement. The foundation footing itself has lost bearing and a section of the house is going down with it. That is what helical piers are for.

The tell is usually where the damage shows. Sloping floors with no exterior cracking points inward, to the crawl space. Stair-step cracking through exterior brick, a chimney separating, or doors sticking on one end of the house points outward, to the footing.

Why Houses Settle Here

Mostly the clay. Triangle soil swells as it takes on water and shrinks as it dries, so a foundation resting on it rides up and down with the seasons. That is also why cracks often look worse in a dry spell and ease off after rain — the ground is moving, not the house alone.

Water makes it worse in both directions: chronic moisture under the house softens the soil that the crawl space supports bear on, and poor drainage around the perimeter keeps the clay outside in a permanent swell-and-shrink cycle. Which is why the drainage half of a quote is not padding — it is the reason the movement started.

How Urgent Is It?

Most settlement is slow, and a house that has moved a little over many years is not about to fall down. What matters more than the amount of movement is whether it is still moving. Cracks that reopen after being patched, doors that get harder to close month by month, or gaps that visibly widen are active settlement and worth acting on. Old, stable cracks that have not changed in years are a different conversation.

A simple way to tell: mark the ends of a crack with a pencil and date it. If it has moved in three months, it is active.

How We Fix It

After inspection, we address both the symptom and the cause. Support jacks reinforce sunken or under-spanned areas, sister joists reinforce weakened floor joists, and drainage and moisture control — French drains, sump pumps — address water intrusion before it does more damage. Where a foundation has lost bearing support entirely, helical piers lift and permanently stabilize it. If chronic moisture has led to mold, we remove it and fix the moisture source so it doesn't come back.

Catching a sinking foundation early keeps repairs smaller and cheaper. The longer it's ignored, the more the floors, walls, and framing move with it.