Foundation Underpinning Castle Hills, TX.
Underpinning carries your slab past the deep, seasonal clay under Castle Hills and seats it on ground that holds. Galvanized steel piers, a written engineer-backed plan, and a lifetime transferable warranty.
Many of the slabs poured across Castle Hills when the area was first built have already moved at least once. Decades of wet winters and bone-dry Augusts have cycled the clay underneath them, and the cracks over a doorway or the door that suddenly drags are usually that history surfacing. Underpinning is how you stop the cycle for good, by extending support below the soil that keeps shifting and transferring the home's weight onto strata that actually carry a load.
The catch in this pocket of Bexar County is depth. The reactive clay here runs deep enough that a short pier can find early resistance on a dense clay lens and feel solid while it is still sitting inside the moving zone. Getting underpinning right in Castle Hills means knowing how far down the active soil goes on your specific lot before you decide where, and how deep, the piers belong.
The clay under Castle Hills, and why it dictates the repair
The soils through this part of Bexar County are largely the Houston Black series, dark, high-plasticity prairie clay with a plasticity index that often runs from roughly 40 to over 60. That number is the whole story: it tells you how aggressively the ground swells when it takes on water and shrinks when it gives it back. A wet winter followed by a dry summer can move a slab measurably in a single year, which is why patching a crack rarely holds for long.
Most of that movement happens in what engineers call the active zone, the depth over which seasonal moisture swings actually matter. In Central Texas that band typically reaches 8 to 15 feet below grade, but it isn't uniform. Drainage patterns, nearby impervious cover, and big thirsty trees all change where it ends on a given property.
That last factor catches a lot of older Castle Hills lots. Mature live oaks and Arizona ash can pull moisture out of the soil well below 10 feet during a drought, so a home shaded by a large canopy may need its piers driven deeper than an identical house two doors down with an open yard. We don't assume a depth. We let the soil and the drive pressure tell us where stable ground begins.
How a Castle Hills underpinning project runs
Free elevation survey
We map the entire slab to within plus or minus 0.01 in. (1/64 in.), pinpointing the high and low spots and the magnitude of movement across the footprint.
Engineered pier plan
Pier locations and spacing are set from your survey numbers and load paths, not a generic grid, so the plan answers your home's actual distortion.
Drive, lift, and lock
Galvanized steel piers are driven hydraulically through the active clay to refusal on load-bearing strata, the slab is raised, and the weight is transferred onto steel.
Re-survey and warranty
We re-shoot the elevations to document the recovered lift, then leave you with written results and a lifetime transferable warranty.
Why driven steel
Pressed-concrete piers are stacked in segments and rely on friction and the home's own weight to seat, in deep, plastic Houston Black clay, they can stop short inside the zone that's still moving.
Steel piers are driven hydraulically until they meet real resistance, and the drive pressure at every pier is logged. That gives a verifiable installation depth for the whole job instead of a guess.
Castle Hills underpinning questions
What will underpinning a home in Castle Hills actually cost me?
How deep do the piers have to go on a lot like mine?
Half my floor slopes one way and another spot feels raised, what's going on?
Once you underpin it, can the foundation move again?
Should I change how I water the yard after the work is done?
Do we have to move out while the crew works?
Is a warranted underpinning repair a help or a hurt when I sell?
Book your free
foundation inspection.
Tell us where you are and what you’re seeing. A GroundLock structural advisor confirms within one business hour.
All foundation services in Castle Hills
Every GroundLock service, available throughout Castle Hills and the surrounding area:
Get your free foundation inspection.
A licensed inspector measures your slab elevation to ±0.01 in. (1/64 in.) and gives you a written, engineer-backed plan with zero pressure.