Slab Foundation Repair San Antonio, TX

Slab foundation repair in San Antonio means stopping a concrete pad that is moving on expansive clay, then lifting it back toward level. Most north and east Bexar homes sit on slab-on-grade: the floor is the foundation. When smectite clay swells after rain and shrinks in drought, the slab drops, brick stair-steps, and doors stop latching.

We diagnose with a free elevation survey, quote pier count and depth in writing, and install steel push piers or helical piers to soil that actually holds. Foam is for small, stopped voids. It is not a substitute for piers on an active slab.

Signs your slab needs repair

One hairline drywall crack after a dry summer is common here. Call when several signs stack. Full homeowner checklist: signs of foundation problems.

• Cracks in drywall around doors and windows, especially if they grew after rain
• Doors and windows that stick, drag, or will not latch on more than one wall
• Floors that slope, ridge, or send a marble rolling toward a corner
• Exterior brick cracks in a stair-step pattern through mortar
• Gaps between walls and ceiling, or between the garage slab and the house
• Cabinets pulling from walls or crown separating at corners

Why north and east San Antonio slabs fail first

Smectite-rich clay dominates Stone Oak, Converse, Cibolo, and the I-35 corridor. That soil absorbs water like a sponge, then cracks when it dries. Slab homes built between 1960 and 1990 on minimal footings are especially vulnerable. Post-tension slabs from the 1990s–2000s boom are not immune. Cables hold the concrete together, but perimeter settlement still cracks brick and twists door frames.

Cut-and-fill lots make it worse. One corner sits on compacted native clay. The garage sits on fill that was never densified. An elevation survey shows where corners dropped, not just where drywall cracked. That is the difference between a repair plan and a guess. Soil science detail lives in our expansive clay soil guide.

Citywide average for all foundation types is about $12,663. Your number is pier count times installed cost, plus drainage if water still pools at the footing. Method-by-method ranges: foundation repair cost in San Antonio.

Steel push piers vs helical piers vs pressed concrete

San Antonio forums repeat one warning for a reason: pressed concrete pilings are the cheap default, and they often never reach load-bearing strata in this clay. Segments stack until the press meets resistance, which can be a dry clay lens, not rock. They do not interlock well. They can shift when the next drought hits.

Steel push piers are driven in sections from the slab edge until they seat on competent soil or refusal. That is the standard permanent fix for perimeter settlement on north and east side homes. Helical piers screw in under torque. They suit tight access, lighter loads, porches, and additions where vibration must stay low. We do not sell one system for every house. The survey picks the method.

Interior piers are sometimes required when the center of the slab dropped, not only the perimeter. That means limited interior breakouts and floor repair after. A contractor who never mentions interior readings on a badly dished slab is selling the easy work, not the house.

How to read a pier quote without getting burned

Pier count must match elevation data. Twelve piers is not automatically a scam on a large footprint with two dropped corners. It is a problem when nobody shows you the numbers, marks locations on a floor plan, or explains why a hairline crack needs a full perimeter. Get a second written quote against the same survey if the first visit felt like a close.

Depth clauses matter more than most homeowners realize. A price that is only good for the first 20 or 30 feet can add $1,200 or more once piers go deeper. North of Loop 1604, you are closer to competent material. Further south and east, clay is deeper. Ask, in writing, whether extras per foot apply and at what depth.

Written warranty on the structural work is standard. Lifetime claims are only as good as the company that still exists in five years. We put the warranty in writing and do not hide behind a new DBA. If a seller hands you paperwork from a firm that changed names twice, treat that as a risk, not a feature.

When polyurethane injection is enough

Polyurethane fills voids and lifts slabs that have only minor settlement, often under an inch, and have stopped moving. It is faster and cheaper than piering when cracks are stable year over year and doors still close. If cracks reopen after every rain cycle, the slab is still active. Foam will not hold. Piers are the permanent answer, then foam only for leftover voids if needed.

Do not foam a house slab that needs house leveling with steel. That is how you pay twice.

Hydrostatic plumbing tests before and after lift

Under-slab drain lines, often PVC through beams, can crack or belly when a slab is lifted. Local homeowners who skip this step find out when a warranty requires a passed test and the line fails. Hire an independent plumber for a hydrostatic test before work and after lift. Typical third-party cost is about $300–$500. We do not sell plumbing. We will wait on a failed test before we lift, because saturating clay under a repaired slab is how you undo the job.

If the test fails, tunneling or lining is a separate plumber scope. Budget for it. Do not let a foundation company test their own lift and mark their own homework if you can avoid it.

Our slab repair process

Free elevation survey. Written scope with pier type, count, and depth assumptions. Independent hydro test when a lift is planned. Steel piers installed along the dropped perimeter, lifted in increments so plumbing and finishes are not shocked. Final elevation check. Most residential slab repairs in San Antonio take 1–3 days. You can stay in the home. Work is along the exterior unless interior piers are in the plan.

Pair piering with drainage correction when water still pools at the slab edge. Piers without drainage fight the same clay cycle every season.

Post-tension slabs, insurance, and selling

Post-tension cables do not make a slab invincible. They reduce some cracking. Perimeter drop still happens. We work around cables rather than pretending they replace piers. Gradual settlement is typically excluded from Texas homeowners insurance. Sudden movement from a covered plumbing leak may qualify. We document elevations and photos if you file. We do not promise coverage.

Selling? Buyers and inspectors in this market expect a report. A repaired slab with written warranty is easier to close than undisclosed stair-step brick. If you are not sure you have a slab versus a crawl space, read slab vs pier and beam or book a free inspection. Crawl space homes need pier and beam repair, not slab piers.

Where we stabilize slabs most often

Weekly work in Stone Oak, Converse, and Cibolo. After repair, keep moisture consistent: soaker hoses 12–18 inches from the foundation in drought months, gutters that actually discharge away from the pad. Prevention is cheaper than a second lift. It will not reverse settlement that already happened.

Related guides

• Foundation repair cost in San Antonio [2026]
• San Antonio expansive clay soil guide
• Slab vs pier and beam: how to tell what you have

Call (830) 244-0222 for a same-day slab inspection in San Antonio. We serve Bexar, Comal, Kendall, and Guadalupe counties. Written estimate before any work begins.