Slab Foundation Repair Alamo Heights, TX.
Mid-century homes near the Olmos Basin sit on some of the most reactive clay in Bexar County. We measure the movement first, then drive galvanized steel piers past the active zone to bearing.
A 1955 ranch house off Broadway is working against a much harder ground than a newer build out on the thin Edwards limestone soils a few miles west. The reason is the dirt directly under the slab: high-plasticity Houston Black-series clay, with plasticity indices that commonly land between 40 and 60, threaded through the Olmos Basin drainage corridor. That soil swells when it rains and shrinks when it dries, and an older, shallow-footed slab rides every inch of that motion.
The clay here rarely fails all at once. It moves slowly and on a cycle, year after year, through an active zone that runs from the surface down to roughly eight to fourteen feet in Central Texas. The job is to read which way a given slab is moving before anyone picks up a tool, and that starts with measurement, not a sales pitch.
Center-lift, edge-lift, and why the pattern decides the plan
Two slabs on the same block can be failing in opposite directions. When a hot Alamo Heights summer dries the perimeter faster than the interior, the edges settle and the middle stays relatively supported, engineers call that center-lift. Flip the moisture: a leaking line or heavy fall irrigation recharges the perimeter clay while the interior stays dry, and the edges rise instead, an edge-lift condition that jams interior doors and fans cracks across hallway drywall.
Telling those two apart matters because they call for piers in different places. Edge drop, center heave, and differential settlement each leave a distinct fingerprint in the elevation data and the cracking. Guessing from where the cracks happen to show is how a slab gets piered in the wrong spots.
That is why every job begins with a measured deflection profile rather than a visual once-over. The crack patterns, stair-step separation in the brick, diagonal lines off window corners, gaps at partition walls, confirm what the survey already told us.
How a GroundLock slab repair runs
Free elevation survey to 1/64 in.
We shoot the whole slab on a grid, inside and around the perimeter, mapping elevation to plus or minus 0.01 inch so the low spots are facts rather than guesses.
Engineer-backed written plan
The deflection map and crack survey become a plan that names pier locations, target bearing depths, and the order of the hydraulic lift.
Drive, lift, and transfer load
Galvanized steel piers are driven hydraulically past the active clay to load-bearing strata, then the slab is raised toward level and its weight is set down onto the steel.
Re-survey and warranty
We measure the finished elevation, document it, and leave the piered work under a lifetime transferable warranty. Most homes stay occupied the whole time.
Keeping the clay quiet between seasons
Steady soil moisture is the single biggest lever a homeowner controls. A few habits go a long way on high-PI clay:
- Slope the finish grade at least 6 inches over the first 10 feet away from the foundation so rain drains off instead of ponding against it.
- Run a soaker hose or drip emitters 18 to 24 inches out from the perimeter during long dry spells, even watering beats heavy and occasional every time.
- Treat a door that suddenly sticks or drifts open as an early warning; it is cheaper to act then than after the brick cracks.
- Account for the big live oaks and pecans common here, a tree whose drip line reaches the slab can pull serious moisture from one side of the house.
- Ask any contractor to name the bearing stratum they are driving to; vague talk of hitting 'refusal' with no penetration criteria is a red flag.
What bearing depth actually buys you
Pressed-concrete piers stop inside the same clay that moved the slab in the first place. Our steel piers advance through that zone and develop capacity in the competent layer below, dense caliche, compacted terrace gravels, or weathered bedrock, depending on where you sit relative to the Olmos Basin alluvium.
The hydraulic driving pressure is read in real time, so the crew and the reviewing engineer can confirm each pier reached bearing before any load goes on it.
Questions Alamo Heights homeowners ask us
My house is from the 1950s, is it too old to pier safely?
What will a slab repair here actually cost me?
Why won't you use concrete pressed piers like some other companies?
My doors stick but I don't see cracks, is that a foundation issue?
There's a big live oak right next to the house. Does that matter?
How precise is the free elevation survey, really?
If I sell, does the warranty go with the house?
Will I have to move out while the crew works?
Book your free
foundation inspection.
Tell us where you are and what you’re seeing. A GroundLock structural advisor confirms within one business hour.
All foundation services in Alamo Heights
Every GroundLock service, available throughout Alamo Heights and the surrounding area:
Get your free foundation inspection.
A licensed inspector measures your slab elevation to ±0.01 in. (1/64 in.) and gives you a written, engineer-backed plan with zero pressure.