Foundation repair in Las Palmas, where flat ground holds water in the clay.

The houses on top of that are mostly 1950s and 1960s slab-on-grade tract homes, now six or seven decades into the cycle. Old enough that nearly every one of them has cracks, and old enough that most of those cracks stopped moving years ago. The elevation survey is what separates the finished ones from the working ones, and it costs nothing.

LAS PALMAS, LOMA PARK, EDGEWOOD AND PALM HEIGHTS, THE FLAT WEST SIDE STREETS INSIDE 78237, WORKED ON OUR DAILY BEXAR COUNTY ROTATION OUT OF THE VANCE JACKSON SHOP.

The ground under 78237

Branyon clay at twelve percent linear extensibility, on ground that will not drain itself.

The dominant soil across this part of the West Side is Branyon clay on zero to one percent slopes, with Lewisville also mapped through the area. Branyon is deep blackland terrace clay, and its linear extensibility is 12 percent. Linear extensibility is simply how much the soil changes length as its moisture changes, so a 12 percent rating means a column of this ground shrinks about an eighth of its height going from wet to dry and swells back when the rain comes. That is at the strong end of the scale for Texas clay soil, and it is the same family of ground the deeper south side rides.

The slope figure matters as much as the clay figure, and it is the part most homeowners never hear. A lot with real fall sheds most of a heavy rain before it ever soaks in. A Las Palmas lot does not. At zero to one percent the water stands, works its way down, and charges the clay completely. Then August pulls it back out of the exposed perimeter while the slab keeps the middle shaded and damp. That difference between a dry edge and a damp center is the mechanism behind most of what we measure here. The perimeter drops while the middle stays where it was, and it runs on the weather calendar, worst at the end of a long dry summer.

A neighborhood of tract-era slabs

Six or seven decades of cycling under 1950s and 1960s concrete.

The housing here is consistent in a way that actually makes diagnosis easier. These are mostly postwar slab-on-grade tract homes from the 1950s and 1960s, poured before the heavier reinforcement and engineered pads that came later, and every one of them has now been through sixty-odd annual swings of this clay. Cracks are not news in this neighborhood. A drywall crack above a door, a hairline at a window corner, a stair-step in the brick out front: most houses on these streets carry a few, and most of those stopped widening long before the current owner bought the place.

What separates a finished crack from a working one is measurement rather than appearance. A floor elevation survey reads the whole slab against itself and shows where the floor actually sits, and laying that map over where the cracks are tells us whether the house is still moving and which way. Where it is, the answer on ground this active is support that bypasses the layer doing the swelling, which is what steel piers and hybrid piers are for. Where it is not, we write down the numbers, hand them to you, and you keep your money. The survey gives you a baseline either way, which is worth having on a slab this old.

The cheapest fix on this ground

On a flat lot, drainage is the first thing to correct and sometimes the only thing.

At zero to one percent you cannot rely on gravity to do anything for you. Gutters that dump at one corner, a flower bed built up against the brick, an air conditioner condensate line that runs onto the same square foot of soil every day of summer: each of those holds one stretch of clay at a different moisture than the rest, and uneven moisture around a slab is what drives the damage. Getting water away from the foundation and keeping what is left even all the way around is the whole preventive game on Branyon clay. In a long drought the same logic runs in reverse, and a steady soaker hose laid an even distance out from the perimeter keeps the edge from drying ahead of the center.

When the grade itself is the problem, correcting it is its own scope rather than a pier conversation. Drainage correction reshapes the ground and routes the water out, and a French drain carries it off a lot that has nowhere else to send it. Both run well short of a foundation repair, and on soil that swells this much they are often the thing that stops the cycle rather than just slowing it. If that turns out to be the whole answer at your house, you will hear it at the inspection.

Costs, warranty and inspections

The straight numbers on foundation repair in Las Palmas.

Nearby

Also serving the communities around Las Palmas.