Slab Foundation Repair Cibolo, TX.

The clay under your slab is doing the moving

A slab in Cibolo isn't resting on solid ground so much as floating on it. The Cibolo Creek floodplain left behind deep alluvial clays closely related to the Houston Black series that defines the Blackland Prairie, and a lot of that material carries a plasticity index north of 40. Soil that plastic behaves almost like a slow gel: it swells through a wet winter and shrinks hard through a Central Texas drought, lifting and dropping the concrete above it by the season.

When that clay dries and pulls away from the underside of the slab, support disappears from the middle or the edges. Engineers call those two failure modes center lift deficiency and edge settlement, and in Cibolo you often see both on the same house. Nearness to the creek makes subsurface moisture uneven, a perimeter beside a drainage swale can stay damp while the street side bakes dry, so the slab moves differentially rather than settling as one piece.

That uneven movement is what you actually feel. A differential of a fraction of an inch across a room is enough to rack a door frame, crack the drywall above a window, and open a seam where the crown molding meets the ceiling. Reading those symptoms correctly is the difference between fixing a mapped problem and chasing cracks around the house.

How a Cibolo slab repair actually goes

Why steel piers, and why they go so deep here

Pressed-concrete piers stop at the first depth where the soil pushes back, and in the Cibolo Creek corridor, that first resistance is usually still inside the active clay that's been moving the slab all along. A pier that terminates in moving soil rides the same seasonal cycle the slab does. That's the whole reason we don't use them.

Our galvanized steel piers are driven past the shrink-swell zone to the stable, load-bearing strata underneath. Because repeated wetting from the creek keeps these clays cycling deeper than homeowners expect, reaching competent material here can mean anywhere from roughly 10 to 25-plus feet, depth isn't fixed, it's driven to refusal under hydraulic pressure. Reaching below the active zone isn't a nicety; it's the entire premise of the method.

One sequencing note specific to slab homes: if there's any sign of a plumbing leak, get the lines pressure-tested before repair, not after. A failed test doesn't disqualify the home. It just means the plumbing gets addressed alongside the piers, because free water under the slab feeds the bearing soil at the worst possible spot and can outrun any drought cycle.

Protecting the repair from the surface down

Piers arrest what's already settled, but they don't change how the clay behaves. A few habits keep the rest of the slab from moving on you:

• Grade the soil to fall at least six inches over the first ten feet away from the foundation, ponding against a floodplain slab keeps the perimeter clay saturated and amplifies movement.
• Run a drip-soaker line 12 to 18 inches out from the beam during drought to hold moisture steady, but keep it back from the stem wall so you don't oversaturate the bearing soil.
• Keep drainage and roof runoff moving away from the slab so the soil isn't soaking on one side and shrinking on the other.
• Watch large trees near the slab, their roots concentrate drying, which is why so much movement shows up at a single corner.
• Re-check your elevation benchmarks at six and twelve months after the lift to confirm the repaired sections are holding.
• Pair the structural work with erosion control on sloped or creek-adjacent lots where surface water is cutting toward the foundation.

Cibolo slab repair questions, answered