Foundation repair on San Antonio's West Side, where the ground moves less than the houses do.

The housing does the rest of the work. Much of the West Side went up between about 1900 and 1940, early bungalows and small frame homes on pier and beam, with slab infill filling the gaps later. Those homes were built before modern grading practice, on flat lots that never drained themselves, and that combination explains more sagging floors and racked door frames out here than the soil ever has.

PROSPECT HILL, AVENIDA GUADALUPE, CATTLEMAN SQUARE, THE WEST END AND THE STREETS AROUND OUR LADY OF THE LAKE, A SHORT RUN WEST OF DOWNTOWN AND INSIDE OUR EVERYDAY BEXAR COUNTY ROTATION.

The ground under the near West Side

West Side San Antonio sits on Lewisville silty clay, moderate soil on a flat lot.

The USDA map unit under most of the near West Side is Lewisville silty clay, 0 to 1 percent slopes, about 90 percent Lewisville with roughly 10 percent Branyon in the mix. Its linear extensibility is 7.5 percent, and that is the number that matters most to a foundation. Linear extensibility measures how far a soil sample swells and shrinks as its water content changes, so a high figure means ground that lifts in a wet spring and drops away in a dry August. At 7.5 percent Lewisville is moderate. The Branyon and Houston Black clays that take over west and south of here run closer to 12 percent, and those are the ones behind the dramatic San Antonio clay stories. On the West Side the clay is a background character rather than the lead.

The slope figure in that map unit name is the part homeowners actually feel. Zero to 1 percent is flat, and flat lots do not shed water. Roof runoff, a hose bib left running, a neighbor's regrade and a hundred years of added walkways all end up parked against the foundation instead of heading for the street, and soil that stays soaked loses bearing strength even when it is only moderately expansive. That is why drainage correction settles more West Side houses than piers do, and why an inspection out here starts with a slow walk around the perimeter looking at where the water lands.

A century of pier and beam

Early bungalows and frame homes built before modern grading practice.

Much of the West Side's housing dates from roughly 1900 to 1940. Early bungalows and small frame homes, nearly all of them originally built on pier and beam with a crawlspace underneath, with later infill dropping slabs into the gaps. A single block can carry both systems, and the two fail in completely different ways. A slab telegraphs its movement upward into brick and drywall. A pier and beam house tells you from the floor first, with a dip toward the center of a room, a bounce when you walk across it, and a gap opening along a baseboard.

That difference changes the repair entirely. On a pier and beam house the work happens underneath, replacing rotted or split cedar posts, resetting blocks and shims, sistering a cracked joist, and getting the crawlspace dry so the cycle does not start over. It is a different trade from driving perimeter piers and it is usually a smaller invoice. Our pier and beam foundation repair page walks through the method, and crawl space moisture control covers the part that keeps the fix from unwinding. Where a West Side house does need piers, Motmot installs steel and hybrid piers only, pressed to refusal, at $600 to $1,000 each, and the pier work carries a lifetime transferable warranty.

Old lines under old houses

On the West Side a plumbing leak moves a foundation more often than the clay does.

When a West Side house moves in a way the weather does not explain, the next suspect is water underneath it. These blocks were plumbed with cast iron and clay long before anyone poured a slab here, and those lines are decades past their design life. A sewer leak carries fines out from under a footing or a pier pad. A supply leak keeps the soil saturated through seasons that should have dried it out. Either way the bearing soil goes soft in one spot while the rest of the lot behaves, which is exactly the uneven pattern that shows up on the elevation survey.

The order of operations matters more than the diagnosis. A hydrostatic plumbing test isolates the leak before anyone talks about support, because supporting a house over a line that is still leaking only buys time. We measure first, say plainly when the plumber should go ahead of us, and about a third of the inspections we run end with no repair needed at all. The elevation survey and the written report are free whichever way it lands, and ICC-certified inspectors are the ones taking the readings.

Costs, warranty and inspections

The straight numbers on foundation repair in West Side San Antonio.

Nearby

Also serving the communities around West Side San Antonio.