Foundation repair in Castroville, where the Medina River valley widens the moisture swing.

Valley bottomland takes water differently than upland ground. It soaks through when the river runs high or a storm parks over the watershed, then gives that water back across a long dry summer. A soil in this range swinging through a wide moisture swing can move a slab about as far as a stronger clay that never gets fully soaked, which is why drainage around a Castroville house matters more than the soil number on its own.

AREAS WE SERVE IN AND AROUND CASTROVILLE, FROM THE HISTORIC DISTRICT AND THE MEDINA RIVER BOTTOMLAND TO THE US 90 CORRIDOR AND THE NEWER SLAB SUBDIVISIONS, WEST OF SAN ANTONIO AND INSIDE OUR NORMAL DAILY RUN.

The ground in the valley

Castroville sits in the Medina valley, where the survey marks the river-bottom ground as occasionally flooded.

Monteola and Quihi are the soils the survey maps around Castroville, and this ground reads 7.5 percent linear extensibility. Linear extensibility is the plain measure of shrink and swell. It says how far a soil expands as it takes on water and how far it pulls back as it dries, so a high number means ground that travels a long way between a wet spring and a hard August. At 7.5 that is moderate. The Houston Black and Branyon clay running under most of Bexar County sits near 12 percent, and houses over there take a harder ride than houses here do. Our foundation risk map scores ZIP 78009 at 56 out of 99, in the elevated band rather than the high one, and that matches what we read off Castroville floors.

The flood classification is the part that changes the work. Occasionally flooded means the river-bottom ground here is low enough, often enough, to take river water. Bottomland does not wet from the top down a few inches the way an upland lot does. It soaks through, and then it gives that water back across a long dry summer. The result is a wider moisture swing on a milder soil, which is why Castroville slabs respond to wet years and dry years more sharply than the number alone would suggest. Drought pulls the dried edges down, and the first hard rain after it heaves the clay back unevenly. Reading which half of that cycle a house is in is what the free elevation survey is for.

The two kinds of building here

Nineteenth century stone walls and modern slabs get read two different ways.

Castroville was settled in 1844 by Henri Castro with colonists from Alsace, and the stone and limestone buildings they put up are still standing. Those walls do not sit on an engineered slab. They sit on stone footings laid on valley ground, and they were built with soft mortar joints that take up small movement instead of resisting it. A hairline in a joint that has been there since the 1800s is usually history rather than news. What matters is whether the pattern is still opening, and the only way to settle that is to measure the floor and come back to the same points later. Raised and pier and beam structures in town get the same treatment, and a measured lift on an older building is worked in small increments for the same reason the mortar was soft in the first place.

Modern Castroville is slab on grade like the rest of the metro, and those houses read the way slabs read everywhere on moderate clay. A corner dries out, the edge drops, doors start to rub in late summer, and brick stair-steps above the corner that moved. Where the readings call for support, the fix is steel or hybrid piers pressed to refusal on bearing strata below the zone the weather reaches, then a measured lift back toward the original plane. Piers run $600 to $1,000 each regardless of method, and every pier we set carries a lifetime transferable warranty that follows the house to the next owner. The method rundown is on our slab foundation repair page.

Where the water goes

In the Medina valley the drainage conversation comes before the pier conversation.

About a third of the inspections we run end with no repair needed, and in a river valley that share is not an accident. Low, flat lots shed water slowly. Roof water that leaves a downspout and stops short of the grade break sits against the slab, and on ground already prone to taking water, one concentrated wet spot beside a drying perimeter is enough to tilt a reading. Poor drainage does more slab damage in Central Texas than most homeowners credit, and the correction is usually gutters, extensions and grade rather than anything structural. Where the water genuinely needs somewhere to go, drainage correction and french drains are a job of their own.

Plumbing belongs in the same conversation. A line leaking under a slab wets one patch continuously while the rest of the lot cycles with the season, and on a moderate soil that single source can outweigh the weather. When the pattern points that way we send homeowners for a hydrostatic plumbing test before we scope anything, because fixing the leak and leaving the slab alone is sometimes the whole answer.

Inspections are free, including the floor elevation survey and the written report, and they are run by ICC-certified inspectors. If the answer is that nothing needs doing, you still leave with the numbers in writing, and the yearly performance follow-up inspection measures the same points again a year on so you can see whether anything moved. Start at foundation inspection.

Costs, warranty and inspections

The straight numbers on foundation repair in Castroville.

Nearby

Also serving the communities around Castroville.