How to Fix Concrete Cracks

Seal cracks before they get worse.

Small cracks in concrete are normal as it cures and the ground shifts, but water getting into them freezes, expands, and makes them worse. Sealing cracks early keeps a slab lasting much longer.

Clean the crack

Chip out any loose, crumbling concrete and clear debris and dust from the crack with a brush or shop vac. Filler bonds far better to a clean, sound surface.

Fill it

For hairline and small cracks, a concrete crack sealant or patching compound works. For wider cracks, a backer rod pushed in first gives the sealant something to bond to without sinking. Tool it flush and let it cure.

When a crack is serious

Hairline cracks are cosmetic, but wide cracks with one side higher than the other, cracks that keep growing, or cracks in a foundation wall can signal settlement or structural movement and warrant a professional assessment.

Frequently asked questions

How do I fix a crack in a concrete driveway?

Clean out loose material, then fill with concrete crack sealant or patching compound — use a backer rod for wide cracks. Seal early so water can't widen it through freeze-thaw.

When is a concrete crack serious?

Cracks with vertical displacement, ones that keep growing, or cracks in foundation walls can indicate settlement or structural issues and should be assessed by a professional.