Core service

Residential Foundation Repair.

From South San Antonio to North Austin, GroundLock handles the whole foundation problem under one roof, the elevation survey that diagnoses it, the steel piers that fix it, and the drainage that keeps it fixed.

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A door that suddenly drags in August. A hairline crack stepping up through the brick over a window. A kitchen floor that feels like it tilts toward the sink. These are the symptoms Central Texas homeowners learn to recognize, and they almost always trace back to the same culprit, the ground beneath the slab moving with the seasons. The repair has to reach past that moving soil, not just lift the house back into place.

GroundLock works one corridor and one problem: residential slabs and pier-and-beam homes across the San Antonio, Austin stretch. Every job starts with a free elevation survey accurate to ±0.01 in. (1/64 in.) and ends with the foundation carried on galvanized steel under a lifetime warranty that transfers to the next owner. Most projects land between $4,500 and $14,000, financing is available, and you stay in the house while the crew works.

How to tell whether your slab is actually moving

A few signs are cosmetic and a few are structural. These are the ones worth a closer look:

Doors and windows that latch fine in winter but stick by midsummer, seasonal soil swelling lifting the frame
Diagonal cracks running at roughly 45 degrees from a door or window corner, through drywall or brick mortar joints, classic shear from differential settlement
Floors that feel bouncy near a wall or noticeably slope toward one corner of a room
Gaps opening where the wall meets the ceiling, or trim pulling away from the drywall
A separation in the slab itself, often first visible as a crack across the garage floor
A high spot in the middle of the house with low edges, possible center heave, which calls for moisture management rather than piers

Why the soil here moves more than almost anywhere else

The San Antonio, Austin corridor sits on top of two very different ground problems, split by the Balcones Escarpment. East of it, the Blackland Prairie clays carry some of the highest plasticity indices in the country, commonly above 40, sometimes near 60, which means a cubic foot of that clay can swell by roughly a fifth of its volume when it takes on water, then shrink nearly as much when the drought returns. West of the Escarpment, thin residual soils sit over fractured Edwards limestone; they drain fast but erode unevenly, leaving bearing voids that can drop a corner of a slab with little warning.

The concept that ties it together is the active zone, the depth where seasonal moisture actually changes the soil's volume. In Blackland settings that zone usually runs 6 to 10 feet down, and because a covered slab suppresses evaporation, the interior soil stays wetter than the perimeter. That's how the center of a slab can heave upward without any plumbing leak at all. Edge settlement and center heave look similar from the curb but demand opposite responses, which is exactly why guessing from the driveway is a mistake.

Telling those two apart isn't a judgment call, it's a measurement. The free survey maps the full contour of the floor, bay by bay, so the plan that follows is built around what your slab is actually doing rather than a template applied to every house on the block.

What the repair looks like, start to finish

Survey the whole floor

We map every occupied bay to ±0.01 in. (1/64 in.), locating each drop and high spot so we know whether you're looking at settlement, heave, or cosmetic cracking that only needs monitoring.

Drive galvanized steel piers to refusal

Each pier is advanced hydraulically in connected sections through the active clay until measured resistance confirms it has reached load-bearing strata, the galvanized coating handles the calcareous, periodically saturated chemistry of local clays.

Lift incrementally and transfer the load

Crews raise multiple piers at once, in small increments, to bring the slab toward level without racking the structure, then lock the home's weight onto the steel.

Re-survey, document, and warranty it for life

A second elevation survey confirms the lift, the work is documented in writing, and the stabilization carries a lifetime warranty that transfers when you sell.

Why we keep bringing up water

Piers stop the part of the house that sits on steel from riding the seasons again. But the conditions that drove the original movement, sprinklers running tight against the perimeter, a yard that sheds water back toward the slab, a downspout dumping at a corner, are usually still there after the crew leaves. Lift the house without fixing those, and you've reset the clock rather than stopped it.

Two numbers do most of the work. Grade should fall about 6 inches over the first 10 feet away from the foundation, which is the minimum needed to keep surface water from migrating underneath and feeding active-zone swelling. And sprinkler heads should sit 18 to 24 inches back from the wall, so you're not keeping the near-surface clay chronically wet on one side of the house.

That's why a lasting fix often pairs the structural work with drainage correction, erosion control, or regrading, recommended only where it genuinely protects the foundation, never as an upsell.

Questions Central Texas homeowners ask us

My doors only stick in late summer, is that really a foundation issue?

Often, yes. When the Blackland clay dries out and shrinks in summer drought, it can drop a corner or edge enough to throw a frame out of square, then partly recover after fall rains. Seasonal sticking that comes and goes is one of the most common early signs of differential movement, and a survey will tell you whether it's trending worse.

How do I know if it's edge settlement or center heave?

From the survey contour. Settlement shows the perimeter dropping below the interior; heave shows the middle of the slab pushing up while the edges stay put. They look alike from the curb but call for opposite fixes, piers for settlement, moisture management for heave, which is why we measure before recommending anything.

How deep do the piers actually go?

Past the active zone, which in our area commonly runs 6 to 10 feet down, and on into competent load-bearing material below it. We don't drive to a fixed depth, each pier advances in sections until measured resistance shows it has reached refusal in stable strata, so depth varies across your lot.

Why steel piers instead of the concrete pressed piers another company quoted?

Concrete pressed piers are stacked cylinders that often stop short, inside the same active soil that's moving the house, and can drift during the next dry cycle. Galvanized steel piers are driven in connected sections that reach deeper, stable rock or dense stratum. On high-plasticity clay, reaching that depth is what holds.

Do we have to move out while you work?

No, nearly every repair is done with the family still living in the home. You'll hear equipment during the day since most piers are set from the exterior and a few interior access points, but crews clean up before they leave each evening.

Is the lifetime warranty genuinely transferable to a buyer?

Yes. The steel-pier stabilization is warranted for life, and that warranty transfers to the next owner of the home. At resale it becomes a documented, warranted improvement rather than something a buyer's inspector flags as an unknown.

Should I repair before I list, or disclose and let the buyer deal with it?

A documented repair with a transferable warranty usually helps the sale, it removes the buyer's biggest unknown. What actually scares buyers off and dents offers is a disclosed, unaddressed foundation problem, not a fixed one.

How much movement is too much to keep watching?

Minor movement can be monitored over a season or two with door-frame and crack-width checks to confirm the trend. But once differential settlement passes about 3/4 of an inch across a bay, interior finishes start to rack and cosmetic repair costs climb faster than the structural fix, that's usually the point to act.

What does a residential repair typically cost, and can I finance it?

Most homes fall between $4,500 and $14,000, depending on how many piers the surveyed deflection profile calls for and how the wall loads run. Pier spacing is driven by your slab's contour, not a fixed grid, so the survey sets the real number. Financing is available, and the survey itself is free.

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