Foundation Types
Slab Foundation Repair
The short answer
Slab foundation repair stabilizes a concrete slab-on-grade that has settled or heaved, usually by installing piers (pressed concrete or steel) beneath the perimeter to lift and support it. Most Austin homes built since the 1980s are slab-on-grade, and typical repairs run $4,000–$12,000 depending on the number of piers.
Why slabs struggle on Austin clay
A slab-on-grade foundation is exactly what it sounds like: the house is poured on a single reinforced concrete slab sitting directly on the soil. It’s the standard for Austin homes built since roughly the mid-1980s — efficient to build, but with one vulnerability here: it has no buffer between the structure and our expansive clay. When the clay swells and shrinks with the seasons, the slab rides every bit of that movement.
That’s why slab problems in Central Texas usually show up as differential movement — one corner or edge drops (settlement) or the center pushes up (heave) — producing diagonal cracks at door frames, separating brick, and sloping floors.
How slab repair works
The standard repair is underpinning:
- The contractor digs access points around the slab’s perimeter.
- Piers are installed down to stable soil or load-bearing strata — pressed-concrete pilings for most jobs, steel push piers for deeper instability, or helical piers where soil is tricky.
- Hydraulic jacks lift the settled areas back toward level.
- The piers permanently support the foundation at the corrected elevation.
Where the slab’s interior has dropped, crews can pier through the slab or use polyurethane foam or mudjacking to raise it.
What it costs and what protects the repair
Budget $4,000–$12,000 for a typical Austin slab repair; see the full cost guide for the breakdown. Whatever you spend on piers, protect it by controlling water — grading, gutters, and steady summer foundation watering keep the clay’s moisture stable so new low spots don’t develop. Compare your options in pier & beam vs. slab.
Frequently asked questions
How do you repair a slab foundation?
By underpinning it: a contractor installs piers (pressed concrete or steel) at intervals beneath the slab's perimeter, then uses them to lift the settled areas back toward level and hold them there. Interior piering through the slab is used when the center has dropped.
How much does slab foundation repair cost in Austin?
Most slab repairs run $4,000–$12,000. The driver is pier count — 8 to 20 piers is typical — at roughly $300–$800 per pressed-concrete pier or $1,200–$2,500 per steel pier.
Can a slab foundation be fixed permanently?
Piering can permanently stabilize the settled areas, and reputable companies back it with a transferable warranty. But because the surrounding clay keeps moving, controlling water with drainage and consistent foundation watering is essential to prevent new problem areas.
What causes slab foundations to fail in Texas?
Expansive clay. It swells when wet and shrinks in drought, repeatedly lifting and dropping the slab. Add poor drainage, large trees pulling moisture from the soil, or plumbing leaks, and movement accelerates.