Concrete slabs move for different reasons, and the repair depends on which one applies. A slab-on-grade that has dropped usually has a void or a soft subgrade beneath it. Heave often points to expansive clay, frost or a plumbing leak. A hairline crack with no offset is usually shrinkage or a missing control joint; a crack that is offset or still widening points to settlement, heave or an overloaded section. Ground Force Engineering sorts these out before recommending anything.
Repairs range from doing nothing beyond caulking a shrinkage crack, to foam injection under a sound slab, to pinning a structural slab on piers, to saw-cutting and replacing a section with a proper base and reinforcing. Homeowners, warehouse operators and buyers in a real estate transaction get a written evaluation with photographs, a diagnosis and a repair specification a concrete or injection contractor can price.
Scope of services
- Crack mapping with width, offset and pattern recorded against the joint layout
- Elevation survey showing the high and low areas of the slab and the difference between them
- Subgrade probing and void detection at the slab edge and along cracks
- Moisture and drainage review where erosion or a leak is suspected
- Polyurethane foam injection specifications for voids under sound slabs
- Pier support design where the slab carries columns, walls or equipment
- Replacement details with base, vapor retarder, reinforcing and joint spacing
- Load rating of existing warehouse and shop slabs for racking or forklifts
How we approach it
Evaluation begins with a level survey and crack map, then a look beneath the slab wherever access allows: a probe rod at the edge, a core if needed, and the crawlspace or basement side where one exists. The report separates cosmetic cracking from structural movement, and says where monitoring is needed to tell whether the movement is still active. Where a repair is warranted, the specification names the method, the limits on lift, the materials and the acceptance check, so the contractor's bid matches the engineer's intent.