Foundation Leveling Converse, TX.

What the Cibolo Creek clay does to a Converse slab

Drive through Converse after a hard spring rain and the ground is doing something you can't see: the dark Blackland Prairie clay lining the Cibolo Creek tributaries is swelling, pressing up against the underside of every slab in the neighborhood within days. Come a dry July, that same clay pulls back and shrinks away from the footings. The slab rides the difference, and over a single wet-winter-then-dry-August cycle it can move enough to measure.

The series under most of this part of Bexar County is Houston Black, and it isn't ordinary expansive soil. It routinely tests with a Plasticity Index above 40, sometimes 60 or higher, which lands it squarely in the very high volumetric-change category geotechnical engineers use. That number is why a house here behaves differently than one on the sandier ground a few miles away, and why leveling has to be done with the clay's behavior in mind rather than against it.

The active zone, the upper band of clay that actually participates in this seasonal shrink and swell, typically runs 10 to 15 feet deep in Converse. Anything resting inside that band moves with it. A real fix has to reach past it.

Settlement and heave look the same until you measure them

Sloping floors, doors that won't latch, and diagonal cracks at window corners can come from two opposite directions, and telling them apart is the whole job. Differential settlement is when a corner or edge loses support and drops, the clay beneath it desiccated, compressed, or washed out. Differential heave is the reverse: a section rises because clay underneath it swelled. Same symptoms on the wall, completely different repair geometry.

Here's a Converse-specific tell that surprises most homeowners. A door that starts binding at its top corner nearest an exterior wall, especially after a wet stretch, often means the perimeter has heaved while the interior load points held still, the inverse of the dropping-corner story people expect. That's exactly the kind of thing a full-footprint elevation survey catches and a quick walkthrough misses.

So we map your slab to ±0.01 in. (1/64 in.) before recommending a single pier. The survey shows which areas settled, which heaved, and where the original design grade sat, then the repair targets the real differential instead of guessing at it.

How a Converse leveling job runs

Slowing the clay between now and the repair

A few habits genuinely moderate how hard the Blackland clay moves under your foundation:

• Keep positive grade away from the slab, about 6 inches of fall over the first 10 feet so storm runoff sheds instead of ponding against the beam.
• Run a soaker hose roughly 18 inches out from the foundation, not against it, during real drought, slowly, so the clay rehydrates evenly instead of shocking on one side.
• Keep large trees and thirsty shrubs more than 5 feet off the beam; their roots pull moisture out of the clay column and can drag one side down.
• Watch interior doors first, a top corner that starts binding near an exterior wall after a wet season is an early heave signal worth a survey.
• Treat any crack wider than 3/16 inch, or any crack with vertical offset between the faces, as a structural flag rather than cosmetic.

Converse foundation leveling, answered