Foundation repair questions,
answered straight

Hairline cracks in drywall or a stem wall that open in late summer and close after the fall rains are seasonal movement on expansive clay, and most San Antonio houses have them. The ones worth an evaluation are cracks you can fit a coin in, stair-step cracks in brick at a corner or above a garage door that widen year over year, cracks with one side offset from the other, doors and windows that jam year-round rather than in August, and floors that slope enough to feel. Photograph every crack with a coin for scale and write the month on the photo; the pattern over two seasons tells more than any single crack.

That is the clay under the slab shrinking in a dry August and swelling back after the rains, which moves the door frame a fraction of an inch each way. On its own it is not a repair; it is a reason to keep the moisture around the foundation even with a soaker hose and to fix any downspout that dumps at a corner. It becomes a foundation problem when the door stops closing in the fall too, when a crack opens above the frame, or when an elevation survey shows the corner has dropped an inch or more against the rest of the house. That is when the evaluation turns into a pier plan.

A slab that is high in the middle and low at the edges is almost always water under the interior and dry clay under the perimeter. In 1950s to 1980s San Antonio homes the usual cause is a cast iron drain line that corroded through under a kitchen or bath and has been wetting the clay for years, heaving that part of the slab, while trees and a dry summer pull moisture from the edges. A hydrostatic plumbing test confirms it. Fixing the leak comes before any piers; otherwise the lift is fighting a slab that keeps rising.

Typical San Antonio ranges in 2026: pressed concrete pilings $350 to $600 per pier, pressed steel piers $1,000 to $1,800, drilled bell-bottom piers $1,200 to $2,200, helical piers $1,500 to $3,000. Most homes need 8 to 12 piers, so a typical slab repair lands between $4,500 and $14,000, and a major repair with 20 or more piers runs $15,000 to $35,000 and up. Pier and beam leveling runs $1,500 to $5,000 before any rotted sill or beam is replaced. Drainage correction and root barriers often cost less than piers and are sometimes the whole fix. Every number goes in a written proposal after the evaluation.

Most residential evaluations in San Antonio are free, and the crew walks the house, shoots elevations, maps the cracks and tells you whether it needs piers, drainage or nothing. A fee of up to $250 applies when the evaluation is for a real-estate transaction and needs a written report, or when a paid inspection is requested rather than a repair proposal. An independent Texas licensed engineer's report is separate, $400 to $900, and is worth it when a lender, a buyer or an insurer will need it. Any fee is stated before the visit is scheduled.

The pier type and the soil. Pressed concrete pilings are precast cylinders pushed into deep clay with the weight of the house, fast and cheap, and they suit most of the clay south and east of the Balcones fault. On the limestone north side they refuse within a few feet, so the plan moves to steel piers that reach a consistent bearing at two to four times the price each, though usually with fewer points. Drilled and helical piers cost more again and are used to an engineer's plan, next to stone walls, or under additions. Access matters too: interior piers under a slab mean breaking out floor and patching it.

The soil decides more than the salesman. In deep Blackland clay across the northeast, south and the I-35 corridor, pressed concrete pilings reach refusal at a useful depth and have a long track record at the lowest cost per pier. On the north and northwest limestone, in caliche, in fill and wherever pilings stop within a few feet, steel piers press deeper and more predictably to a stable stratum. Mixed lots sometimes get both under one house. Drilled bell-bottom piers come in when an engineer's plan calls for them, and helical piers where vibration next to a stone wall or a light structure matters. The evaluation and the elevation survey pick the method; the proposal explains why.

Before, when a leak is the cause. A hydrostatic plumbing test on the drain lines under the slab is standard before any lift on a 1950s to 1980s San Antonio home, because a corroded cast iron drain wetting the clay is behind a large share of heaved interiors. If the test fails, the drain is repaired first, usually by tunneling under the slab so the floor stays intact, and the piers go in after. A second test after the lift confirms the lift did not open a joint. Skipping the test is how a house gets piered and keeps moving.

Usually, yes. Pier and beam repair in King William, Monte Vista, Alamo Heights, Seguin and the older south side starts with an elevation survey of the floor and a crawl space inspection. Where the piers are sound and the wood is dry, the fix is reshimming and adjusting, $1,500 to $5,000. Where sills or beams have rotted at the corners or piers have sunk or crumbled, those sections are replaced or new piers set on proper footings, $3,000 to $12,000 depending on the rot and the span. A moisture barrier and ventilation keep the crawl space from doing it again. Historic districts review anything visible from the street.

Two soils and a climate that swings. The Balcones Escarpment runs through the metro from southwest to northeast. South and east of it the houses sit on Blackland Prairie clay that swells after a wet spring and shrinks through a dry summer, lifting and dropping the edges of every slab. North and west they sit on Edwards limestone with thin soil, caliche and fill on cut lots, where slabs settle unevenly on a mix of rock and dirt. Add roughly 32 inches of rain that arrives in bursts, drought years like 2011 and 2022 to 2023, live oaks and pecans drinking from one side of the foundation, and cast iron drains leaking under 1950s to 1980s slabs, and the doors start sticking.

On clay, yes. The goal is even moisture around the whole foundation, not wet soil, so the slab does not have a wet edge and a dry edge. A soaker hose 12 to 18 inches from the foundation, run in the early morning or evening on a timer during dry months, is the usual method; do not flood the bed and do not water only one side. SAWS drought stages restrict sprinkler days and hours, and soaker hoses and drip irrigation are treated more leniently but still have time-of-day rules that change with the stage, so check the current SAWS stage before setting a timer. New Braunfels, Seguin, Schertz, Cibolo and Boerne run their own utilities with their own rules.

The deep clay of the northeast and southeast moves most with the seasons: Schertz, Cibolo, Converse, Universal City, Highland Hills, Harlandale and the east and south sides of New Braunfels and Seguin. The 1950s to 1970s slabs inside Loop 410, in Castle Hills, Hollywood Park, Leon Valley and the south side, add leaking cast iron drains to the clay. The limestone north and northwest, Stone Oak, Helotes, Boerne, Garden Ridge and Shavano Park, move less from soil but settle on fill and uneven rock. The historic districts, King William, Monte Vista and Alamo Heights, have pier and beam problems that are wood and masonry as much as soil. No part of the metro is exempt; the failure just looks different.

Six regions and 24 core neighborhoods: Central San Antonio (Downtown, King William, Monte Vista, Alamo Heights), North (Stone Oak, Castle Hills, Shavano Park, Hollywood Park), Northwest and the Hill Country (Helotes, Boerne, Leon Valley, Alamo Ranch), Northeast (Schertz, Cibolo, Converse, Universal City), South and Southwest (Harlandale, Highland Hills, the Southwest Side, Castroville) and New Braunfels and Seguin (New Braunfels, Seguin, Garden Ridge, Live Oak). The list is the core, not the boundary; the rest of the City of San Antonio and the neighboring cities are covered on the same basis, and we are honest about the evaluation window for the far edges.

Evaluations are usually scheduled within a few days, with typical travel from about 25 minutes in Central San Antonio to about 40 minutes out to New Braunfels and Seguin. A house that is moving right now, after a plumbing leak or a sudden drop, goes ahead of routine evaluations. After a flood week or in a drought August the schedule fills, and you are told where you sit before anything is booked. While you wait, photograph the cracks with a coin for scale and note where water pools around the slab after rain.

Usually not for soil movement. Texas homeowners policies generally exclude damage from settling, cracking, shrinking and expansion of the soil, which is most San Antonio foundation movement. The exception is damage caused by a plumbing leak under the slab: depending on the policy and any foundation or seepage endorsement, part of the repair may be covered, often with a cap. A hydrostatic plumbing test, dated photos and an engineer's report are what the adjuster asks for. Read the declarations page and call the agent before work starts, and keep the failed section of drain.

Yes, inside the city limits the City of San Antonio Development Services Department requires a residential repair permit for structural foundation work, and an engineer's letter is often part of closing it out. Alamo Heights, Castle Hills, Shavano Park, Hollywood Park, Leon Valley, Helotes, Boerne, Schertz, Cibolo, Converse, Universal City, Live Oak, Garden Ridge, New Braunfels, Seguin and Castroville each run their own permit office. The contractor pulls the permit and it is included in the written proposal. Historic districts add design review for anything visible from the street.

Yes. The Texas Property Code, Section 5.008, requires the seller's disclosure notice to state known previous structural or foundation repairs. A repair with a transferable warranty, an engineer's letter and an elevation record is usually easier to sell than an unrepaired house with the same cracks, because the buyer's lender and inspector get paperwork instead of guesses. If you are buying, a foundation inspection and, where the inspector flags movement, an engineer's report before the option period ends are the standard protection.

No. Texas does not license foundation repair contractors at the state level; the Texas Residential Construction Commission was abolished in 2009 and nothing replaced it. Structural engineers are licensed by the Texas Board of Professional Engineers and Land Surveyors, which is why an independent engineer's evaluation and letter matter here more than in licensed trades. The things that stand in for a license are the written proposal with the pier plan drawn, the City permit, the hydrostatic test before and after, elevations recorded, and warranty terms you can read. Ask for all five before signing.

Warranty terms are stated in the written proposal for each job, including the term, what it covers, and whether it transfers to the next owner. This website does not promise a warranty, because the terms belong to the contractor who does the work and they vary by method and by what the evaluation found. What a warranty on piers typically does not cover is new movement in areas that were not piered, damage from a plumbing leak or a drainage change after the work, and additions. Read the terms before signing and keep them with the house paperwork.

Ask for an elevation survey, not just a walk-around, and for the pier plan drawn on paper with the count and the locations. Ask which method and why the soil under your house suits it. Ask whether a hydrostatic plumbing test is included before and after. Ask who pulls the City permit and whether an engineer's report is available when a lender or buyer needs one. Ask for the warranty terms in writing and whether they transfer. Then ask whether the house might not need piers at all; a company that never says drainage or watering is selling piers, not evaluating houses.