Foundation Repair for Uneven Floors: Map the Slope Before You Fix Anything

Two foundations, two different uneven floors

Central Texas homes get uneven floors two ways, and the repairs have almost nothing in common. On a slab foundation, the floor is the foundation: when drought shrinks the clay under one edge, the slab follows it down and every room above tilts with it. The telltale is a slope that drains toward an exterior corner, usually with company — stair-step cracks in the brick outside, drywall cracks inside, doors racking near the same corner. On a pier-and-beam home, the floor is a wood structure riding on posts and beams over a crawlspace, and it fails differently: floors get bouncy or soft, sag toward the middle of a room rather than a corner, and the cause is usually a beam, sill, or block that moisture got to — often far cheaper to fix than slab work.

The distinction matters because it flips the repair. Slab settlement gets support — piers below the active clay at the low sections, then a measured lift. Pier-and-beam sag gets carpentry — beams, sills, and blocks in the crawlspace. Selling one house the other house's repair is how uneven floors get expensive without getting fixed.

The floor map: what an elevation survey actually shows

The centerpiece of our free inspection is the floor elevation survey: a ZipLevel altimeter reading 40+ points across the house to a tenth of an inch, drawn into a color-coded map you can hold. Green is level, red is the low corner — and the pattern, not any single number, is the diagnosis. Slopes that all drain toward one exterior corner read settlement at that corner. Slopes radiating away from a center high spot read heave, which has a different cause (water — often a plumbing leak) and a different fix. A random scatter of small readings reads like what it usually is: a house being a house on expansive clay.

The map is also your baseline. Whatever it shows, it's dated — so six months from now, "is it getting worse?" has a measured answer instead of a feeling. If we recommend monitoring, the re-survey is free too.

When an uneven floor is cosmetic — and when it isn't

Here's the honest part most sloping-floor searches never find: some slope is normal. Builders' own tolerances allow noticeable variation in a brand-new slab, and decades of clay seasons add more. The working scale we use in the field: under about half an inch across 20 feet is background noise; three-plus inches is where active movement is the likely story; and the wide country between them is decided by trend — is it moving, or has it been that way since the Carter administration? Direction beats degree, too: a uniform old lean rarely matters, while a newer slope aimed at a corner with fresh cracks around it deserves attention. We wrote a full deep-dive on exactly this call, including how to measure it yourself with a marble and a level: sloping floors — cosmetic or structural?

And some “foundation” slopes aren't foundation at all — a gap opening beneath an interior wall, for instance, is structural and worth measuring, while a hump under one hallway can be a framing or subfloor issue on a pier-and-beam house. The survey sorts these without drama, and “no repair needed” goes in writing when that's what the readings show.

What fixing an uneven floor involves — and costs

When the map says slab settlement, the fix is house leveling: piers installed below the active clay at the low sections, then a lift in measured stages that brings the floor back toward its original plane — with before-and-after elevation maps documenting the recovery. Pricing runs on pier count, not square footage: piers run about $600–$1,000 each installed, a settled corner (4–6 piers) typically lands around $2,500–$6,000, and a full side runs $5,000–$12,000. When the cause is pier-and-beam framing, crawlspace beam and block work frequently lands in the low four figures. The cost guide walks the full math, and every number we quote traces to a reading on the map — never to a quota.