Foundation repair King William.

The homes along King, Madison, and Guenther streets weren't built to modern slab standards, many of them predate the automobile, and they sit on deep river clay a stone's throw from the San Antonio River and the Mission Reach. That combination is exactly what turns a proud Victorian into one with doors that stick in August and a bay window pulling away from its brick. The soil under this neighborhood swells when the river and the rains are up, then shrinks and cracks through a dry Texas summer, and a century-old pier-and-beam or a mid-century slab has been riding that cycle its whole life.

GroundLock works on that movement the way an engineer would rather than the way a salesman would. Before anyone talks about cost or scope, a local inspector shoots a free elevation survey across the whole structure, accurate to ±0.01 in. (1/64 in.), so we know precisely how far the house has drifted and in which direction. From there the fix is galvanized steel piers driven hydraulically past the active clay zone to strata that don't move with the seasons, and in a historic district, doing that with minimal disruption to original finishes matters as much as the numbers.

Why King William foundations drift

This is San Antonio's first historic district, and its lots sit on the deep, high-plasticity clays that follow the river bottom rather than the thin limestone soils out west. Those clays carry plasticity indices well into the 40-to-70 range, which means they expand and contract with real force as moisture moves through them. The active zone, the depth over which that seasonal swelling and shrinking happens, commonly runs 8 to 15 feet below grade here, and near the river it can go deeper where the clay is uninterrupted.

A concrete pressed pier stopped inside that zone doesn't escape the cycle; it just resets the clock until the next wet spell heaves it again. That's why we drive galvanized steel piers past the active clay to competent load-bearing material, monitoring driving resistance in real time so each pier is confirmed to have reached a stratum that actually carries the load. On the older pier-and-beam homes common in King William, that same principle applies to the perimeter beam and interior supports alike.

Water management is half the battle on these lots. Mature live oaks and pecans pull moisture unevenly, river-adjacent grade can trap water at the edge beam, and a century of added-on porches and additions complicates drainage. Getting runoff to fall away from the structure is often the difference between a lasting repair and a recurring one, see our drainage and erosion-control approaches for how we handle the water alongside the piers.

How a King William repair goes

King William foundation questions