Sinking Foundation Repair Cibolo, TX.

A foundation in Cibolo rarely drops all at once. It tilts. One corner over by the downspout goes low, a hallway starts to pitch, and a bedroom door that latched fine last winter now scrapes the jamb. By the time you notice, the soil has already been working on the slab for a couple of seasons, and on the floodplain clays here, that work compounds every dry summer.

The reason is in the ground itself. Cibolo sits on high-plasticity floodplain clay (geotechnically, CH soil with a plasticity index that frequently tops 40) laid down by the creek and never compressed under deep overburden. It drinks water and holds it, swelling when wet and contracting hard when dry. We don't guess at how much your slab has settled, we survey it to within a hundredth of an inch and let the numbers set the plan.

What the floodplain clay does to a slab

The settlement here follows a fairly predictable mechanical sequence. In a drought the clay pulls back from the perimeter beam first, opening a gap that lets the next rain rush straight down alongside the foundation. That re-wetting is never even, it's heaviest near downspouts and shallowest toward the middle of the slab, so the structure rotates rather than dropping uniformly.

All of that plays out in what's called the active zone, the band of soil that wets and dries with the seasons. In Cibolo's floodplain clays that zone runs roughly 8 to 15 feet deep, and year after year the soil beneath the edge of your slab loses the support it once had. A stiff floor system fights the differential movement and hands the stress off to the building as cracks.

One thing worth knowing before anyone quotes you piers: not every low slab is sinking. Over-irrigation can lift the center of a slab instead, and perimeter settlement and center heave call for opposite responses. Treating one like the other makes the damage worse, which is exactly why we start with a deflection map instead of a hunch.

How a Cibolo repair actually goes

Signs your Cibolo slab is settling

A little seasonal movement is normal on Guadalupe County clay. These patterns are the ones that tell us the soil is actually losing support:

• A visibly low corner or a floor that pitches noticeably toward one side of the house
• Stair-step cracks climbing the mortar joints in brick or block veneer
• Diagonal drywall cracks fanning out from the top corners of doors and windows
• Doors and windows racked out of square, sticking, dragging, or no longer latching
• Cracks that widen at the top and pinch at the bottom near corners (a tell for perimeter rotation)
• Gaps opening between the slab and the perimeter beam, or between walls, trim, and ceiling

Cibolo sinking foundation repair, answered