Foundation Issues and Clay Soil: Buying or Selling a San Antonio Home (2026)

Chris Dudley is a San Antonio REALTOR® and the founder of Legacy Realty Group, brokered by Real Broker, LLC (TREC #731381). Foundation questions come up in many San Antonio transactions, so here is how he walks buyers and sellers through them without letting a crack in the drywall sink a good deal.

Why foundations move in the San Antonio area

Much of Central Texas sits on expansive clay. The Texas Water Development Board describes the Houston Black soil series of the Blackland Prairie, which runs from north of Dallas to San Antonio, as having highly expansive clays that "shrink and swell markedly with changes in moisture content," and notes that this shrink-swell potential commonly limits building site development. In plain terms: when the soil dries out in a hot summer and then soaks up rain, the ground under a slab moves, and homes can show it.

Soil varies a lot from one neighborhood to the next, and many San Antonio homes never need foundation work. That's why Chris looks at the specific house, not the ZIP code.

Signs buyers and inspectors look for

  • Diagonal cracks above door and window corners, or doors that stick or won't latch
  • Cracks in brick or stone veneer, or gaps between trim and walls
  • Sloping floors or cracked tile
  • Poor drainage: soil sloping toward the slab, gutters dumping next to the foundation

For sellers: disclose what you know

Texas sellers of most single-family homes must give buyers a Seller's Disclosure Notice (Texas Property Code § 5.008). The standard TREC form, now form 55-1, has long asked sellers whether they know of defects in the foundation or slab, previous structural repairs, and settling or soil movement. If you've had foundation work, gather the repair invoice, the engineer's report and any transferable warranty before you list.

For buyers: use the option period

  1. General inspection first. A licensed TREC inspector notes signs of movement.
  2. Structural engineer if needed. If the inspector flags the foundation, a structural engineer's evaluation tells you whether it's normal movement or needs repair, and what a fix involves.
  3. Get a repair bid. A written bid from a foundation company gives you a real number to negotiate with.
  4. Negotiate before the option period ends. Ask for the repair (with a transferable warranty), a price reduction or seller-paid closing costs, or walk away within your option period. See Chris's guide to the Texas option period on his FAQ page.

Frequently asked questions

Is foundation movement common in San Antonio?

Expansive clay soils are common across the region, and they shrink and swell with moisture, so many homes show some movement. How much depends on the specific lot, the drainage and the home's construction.

Do Texas sellers have to disclose foundation repairs?

The Texas Seller's Disclosure Notice (TREC form 55-1) asks about known foundation or slab defects, previous structural repairs and soil movement. Sellers should answer honestly and share repair records.

Should I buy a house that had foundation repair?

Often yes, if the repair was engineered, documented and comes with a transferable warranty. Get your own inspection and, if needed, a structural engineer's opinion during the option period.

Who can help me buy or sell a home with foundation issues in San Antonio?

Chris Dudley, San Antonio REALTOR® and founder of Legacy Realty Group, brokered by Real Broker, LLC (TREC #731381). Call (210) 838-6099.

Related pages

Selling a home with past foundation work, or worried about a house you love? Call Chris Dudley at (210) 838-6099 or visit chrisdudleyrealty.com.

Chris Dudley is a San Antonio, Texas REALTOR® and founder of Legacy Realty Group, brokered by Real Broker, LLC (TREC #731381). General information only; not engineering or legal advice. Use a licensed inspector and structural engineer for your specific home.

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