Floor Cracks
in Your
Maryland Home

Concrete slabs crack as they cure, and these shrinkage cracks are common and generally not structural. They tend to be hairline width, run in no particular pattern, and don't show displacement, meaning one side of the crack isn't higher than the other.

A settlement crack behaves differently. It's typically wider, a quarter inch or more, shows displacement across the crack, follows a pattern consistent with soil movement below the slab, or shows up alongside other signs like sloping floors or wall cracks elsewhere in the house. If you're only looking at the crack itself and not what else is happening nearby, you're missing half the picture.

In Maryland, slab settlement cracking usually traces back to soil conditions beneath the slab: a void that's formed as soil erodes or washes out, fill material that was never fully compacted, or Piedmont clay that has shrunk and pulled away from the slab during a dry stretch. A crack that's widening over time, or that's paired with a section of floor that feels noticeably lower than the rest, is worth having assessed rather than just patched over.

If it's a stable shrinkage crack, yes, sealing against moisture is a relatively simple fix. A crack tied to settlement needs the underlying cause addressed first, whether that's a void beneath the slab or ongoing soil movement, or the repair reopens as the soil keeps moving. Sealing a settlement crack without addressing what's under it just delays the next crack.

Where the cause is a void beneath the slab, polyurethane foam injection can fill that void and support the slab from underneath, which is an appropriate use of foam. Foam is a tool for concrete lifting, slab repair, and void filling, not a substitute for structural underpinning when a wall or foundation section itself needs support. OBW matches the diagnosis to what the inspection actually finds and says which method the slab needs. Foam work itself is not part of OBW's service line; where the cause is structural rather than a void, the repair is.

We measure the crack width, check for displacement across it, and look at the pattern of the crack itself, then check the rest of the house for signs that point to the same underlying cause: sloping floors, wall cracks, or other settlement signs. OBW's free inspection distinguishes a stable shrinkage crack from a settlement crack before recommending anything. Backed by a written workmanship guarantee, terms vary by service, ask your inspector.