What is slab-on-grade foundation repair?
Most homes built in the Dallas area after the 1960s sit on a slab-on-grade foundation: a single concrete slab poured directly on prepared ground, thickened into deeper grade beams under the perimeter and along interior bearing lines. The grade beams carry the structural load. The flat field of the slab in between carries the floor.
Slab repair means stabilizing that foundation where it has moved, and recovering elevation where it can be recovered safely. In practice that means installing piers beneath the grade beams, down to a layer of soil or rock capable of carrying the load, then transferring the building’s weight onto those piers with hydraulic jacks under continuous elevation monitoring.
What it does not mean is replacing the slab. Full replacement is rare and is reserved for documented, widespread structural failure. If a proposal jumps straight to replacement without an elevation survey supporting it, ask what measurements led there. That evidence-first standard applies across all of our foundation repair work in Dallas, not just slab projects.
Why slabs move in North Texas
The soil across most of Dallas County is expansive clay. It swells when it takes on moisture and shrinks when it dries, and it does this in the upper few feet, the active zone, where a residential foundation sits. A long drought pulls moisture out and the soil contracts. Heavy rain after that drought puts it back and the soil expands. When that happens unevenly across a lot, because of a tree on one side, a downspout on another, or fill that was never uniform, the foundation moves unevenly with it. That is differential movement, and it is what produces the cracks, sloping floors, and binding doors homeowners call about.
What the evaluation examines
Before anyone talks about piers, we measure. A digital manometer records relative floor elevations across the whole plan, producing a contour picture of where the slab sits high and where it sits low. Alongside that, a visual distress survey documents crack locations, widths, and directions inside and out, separations at trim and brick, door and window behaviour, and the condition of the grade and drainage around the house.
The survey also looks for things that change the answer: an addition poured at a different time, evidence of prior repair, a large tree within influence distance of a grade beam, or a wet patch that suggests a plumbing leak rather than soil movement. Those findings determine whether a pier plan is the right response at all.
Types of slab repair we perform
Perimeter underpinning. Piers installed along exterior grade beams where the survey shows the perimeter has dropped. This is the most common scope and the least disruptive, because all access is outside the house.
Interior pier installation. Where an interior grade beam has dropped, piers are required inside the footprint. Access is either by breaking out a section of flooring and slab, or by tunneling in from the perimeter. Tunneling costs more per access point and protects finished floors.
Combined lift with plumbing coordination. On older slabs, we coordinate hydrostatic testing with a licensed plumber before the lift and again afterwards. A leak found before work starts changes the scope. A post-lift test confirms the elevation change did not open a line.
Stabilization without a full lift. Sometimes the correct scope is to stop further movement rather than chase elevation recovery that would crack finishes without improving the structure. We will say when that is the better outcome.
When do you actually need slab repair?
Not every crack means repair. The combination that usually does warrant attention is measurable elevation difference across the plan, paired with functional symptoms: doors binding on one side of the house, diagonal cracks running from door and window corners, separation at the brick veneer, or floors that have visibly changed slope over time.
The combination that usually does not is hairline cracking along drywall seams that opens in late summer and closes after the fall rains, with no elevation variance behind it. That is seasonal movement in clay, and patching it is a decorating job, not a foundation job.
If you are unsure which describes your house, the honest next step is a foundation evaluation rather than a repair quote.
Access, disruption, and restoration
Perimeter work requires a working trench at each pier location, which means excavation through beds, turf, and sometimes hardscape. Irrigation heads and lines are located before digging, and cut lines are repaired. Spoil is staged where you agree it can be staged and removed at the end.
Interior work through the slab means a room becomes a work area, with dust containment and a finished floor to reinstate afterwards. Tunneling avoids that at the cost of more excavation outside and a tunnel that must be properly backfilled and compacted.
Restoration expectations belong in the written scope. Ours states what gets backfilled, what gets replanted, what gets replaced, and what is explicitly excluded, such as interior cosmetic repair of drywall and paint after a lift.
What you receive
Your documented scope includes the elevation survey results, a floor plan marked with pier locations, the pier system specified, the access approach, permit and inspection handling, restoration included, exclusions stated plainly, the schedule, payment terms, and the written warranty. After the work, you receive post-lift elevation records, the city inspection sign-off, and any plumbing test results.
That package is what makes a repair defensible later, to a buyer, an agent, or an engineer. It is also what makes our quote comparable, line by line, against anyone else’s. If you are holding a second proposal right now, our guide on how to compare two foundation repair quotes walks through the comparison properly.
