Concrete Leveling in San Antonio, What Works

Concrete leveling works in San Antonio when the slab that sank is plain flatwork, a walk or a driveway resting on soil that has finished settling. It disappoints when the ground underneath is active expansive clay, because the lift puts the slab back without changing what the soil does next. And it's the wrong tool entirely when the concrete that moved is the house. We don't sell leveling injection at Motmot. We pour replacement flatwork and we drive steel and hybrid piers, so our interest here is simply that you buy the right fix the first time.

What the market is selling

Concrete leveling, mudjacking, slabjacking, and polyjacking are all versions of one move. A crew drills holes through the sunken slab and pumps material underneath it, a sand-and-cement slurry in the traditional version, expanding polyurethane foam in the newer one, until pressure floats the concrete back to grade. The holes get patched and most jobs wrap in a morning. It's a mature trade, and the good outfits do clean work. The two methods differ in price, hole size, and cure time, and we keep an attributed rundown of the numbers in our guide to what mudjacking and foam lifting cost. That page covers the money. This one covers whether the method fits San Antonio ground, which is the question the ads skip.

Where a lift earns its keep

Plenty of sunken concrete in this town deserves a lift and nothing more. A sidewalk panel that dropped an inch and catches your toe. A patio corner that settled after a utility trench was backfilled a little loose. A driveway section that sank over a void that formed once, during construction or an old washout, and finished compacting years ago. In those cases the soil did its moving one time, the slab is otherwise sound, and nothing sits on top of it but air and lawn furniture. Pumping it back to grade costs a fraction of replacement and reuses concrete that still has decades left in it. When an estimator can explain the void instead of just quoting the lift, that work is a reasonable buy, and we refer it out without hesitation.

Why lifts struggle on San Antonio clay

The catch is under the slab. Much of San Antonio sits on expansive clay, soil that swells when it's wet and shrinks hard in drought. A slab on that ground didn't sink because the concrete failed. It sank because the clay under it changed volume, and injection does nothing to change that behavior. Slurry and foam both rest on the same soil that moved, so when the next dry summer pulls moisture out of the clay, the new material rides down with it. Traditional slurry adds real weight while it's at it, which on soft clay can hurry the next drop along. Foam is far lighter, but light doesn't mean anchored.

The pattern to watch is seasonal. A slab that opens a gap in August and closes it by February isn't settling, it's breathing with the clay's moisture cycle, and a lift buys you one flat season before the cycle takes it back. The other repeat offender is water. A downspout dumping at the slab edge, grade sloping toward the house, a leaking irrigation line. Level over an unfixed water problem and you've paid to hide the evidence. Any leveling estimate worth signing names the cause of the sink, not just the price of the lift.

When it stops being a leveling job

Some of the leveling calls made in San Antonio are not flatwork problems at all. The concrete that moved is the garage slab tied into the foundation, or the floor inside the house, or the slab edge under a brick wall. That concrete carries the building, and the soil under it failed several feet down, not in a surface void. Pumping foam or slurry under a settled foundation presses against the very layer that let go, and it holds only until the clay's next cycle. The repair that lasts bypasses the clay altogether. We drive steel and hybrid piers down to refusal at load-bearing strata and rest the structure on those, at $600 to $1,000 per pier, with a lifetime transferable warranty on the piers. Bringing a settled house back toward level is pier work, a different trade from lifting a patio, and it's covered on our house leveling page. If a bid proposes foam as the fix for a moving foundation, get a second opinion before you sign anything.

What we do instead

Motmot doesn't install mudjacking or foam, and this page is no knock on the outfits that do. Our lane is the two jobs injection can't reach. When flatwork is past saving, cracked through its depth, poured on a bad base, or pitched toward the house so it feeds every rain to the foundation, we tear it out and pour it right, on a compacted base with steel in it, finished to a grade that sends water away from the building. That work is described on our concrete flatwork page, and you can ballpark a replacement yourself with the concrete cost estimator before anyone sets foot on your driveway. When the problem is structural, the answer is piers, counted from elevation measurements rather than guesswork. The inspection that sorts one from the other is free, and about a third of the inspections we run end with no repair needed at all.

How to tell which job you have

Before you call anyone, walk the slab and answer four questions.

• What sits on it? Nothing but open air, and it's flatwork, so a lift is on the table. A wall, a post, the garage, or the house itself, and it's structural, so injection is off the table.
• Which side of the joint moved? At the line where patio meets house, look at the gap. A patio that dropped away from a steady house is a flatwork story. A house edge sitting low against a steady patio is a foundation story.
• Does it move with the seasons? Measure the gap in late summer and again after the winter rains. If it breathes, the clay is active and a lift won't hold.
• Where does the water go? Follow the downspouts and the grade during a rain. If water collects at the sunken spot, fix that first, no matter which repair you end up buying.

If the answers point at the house, or you'd rather have numbers than a guess, our ICC-certified inspectors will put an elevation survey on the floors at no charge and tell you which of the three columns at the top of this page you're in. And when pier work does happen, we come back for a performance follow-up inspection every year, so the answer stays measured instead of assumed.