Cracks in Your Floor Often Start With the Soil Underneath It

The cause depends on where you are. In the Piedmont, around Charlotte, Greensboro, Winston-Salem, and the Triangle, clay soils swell when wet and shrink when dry, lifting and dropping the slab on top of them and cracking the concrete over repeated cycles. In the Sandhills near Fayetteville and Pinehurst, sandy soils let water wash out the fine particles that support a slab, opening voids beneath it. Around Asheville and the mountains, hillside lots and heavy rainfall drive runoff and washout under foundations. In coastal markets like Wilmington and Leland, a high water table and saturated sandy soils reduce the ground's bearing strength. Poorly compacted fill under newer homes can be a driver in both states.

It can often be repaired at the cause of the crack. If the crack comes from foundation settlement, a common approach is to underpin the affected footings with piers that reach firmer soil below the layer that moves, soil that carries the load. The piers carry the weight of that section down to that soil. If a settled slab needs raising, concrete lifting with polyurethane foam can fill the voids beneath it and bring it back toward level. Simply patching a crack without addressing why the floor moved does not stop the underlying soil or settlement, so the crack tends to return.

Sometimes. Tile and grout are rigid, so they crack when the floor beneath them flexes or drops. A single cracked tile from an impact is one thing, but tiles cracking in a line across a room, grout splitting along the same path, or tiles loosening and popping often mean the slab or the floor framing below has moved. When that pattern shows up with a sloping floor or other settlement signs, it is worth having the floor inspected to find what is happening underneath.

There is no set price, because the cost follows the cause. A stable shrinkage crack may need no structural repair at all. Settlement may call for piers under the affected footings, and a settled slab may be raised with polyurethane foam, so the price depends on how much of the floor has moved, the repair method that fits, and the soil beneath it. The free inspection finds the cause, and you receive a written estimate at no cost before any work is scheduled.

How foundation repair services are priced

An inspector measures floor elevations throughout the home to map where it has dropped, then inspects the slab, foundation, crawl space, and the soil and drainage conditions around the house to find the cause. You receive a clear explanation of whether the crack is cosmetic or structural, whether anything is still moving, and the repair options that fit your situation. The inspection is free, and HydroHelp911 offers financing options for repairs.