Foundation Crack Repair
Most leaking basement cracks are thin shrinkage cracks in poured concrete that can be sealed from inside by injection. Professional injection typically costs $200–$1,000 per crack, and a DIY polyurethane injection kit costs about $60–$150. Horizontal, stair-step or widening cracks can be structural and need an engineer's opinion.
Last reviewed September 2026
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Is water coming through a wall crack?
During or after rain, look for water or damp staining along a crack in the foundation wall.
Signs it's this problem
- A damp line or trickle of water along a visible crack after rain
- White, powdery mineral deposits (efflorescence) along the crack
- Rust-colored or muddy streaks running down from the crack
- A crack that feels damp even when the rest of the wall is dry
Why it happens
Concrete shrinks as it cures and the soil around it settles, so thin cracks are normal in many foundations. When the ground outside is saturated, water pressure pushes moisture through any crack that reaches the outside.
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Safety: Horizontal cracks, stair-step cracks in block walls, cracks wider than 1/4 inch or walls that bow inward can mean structural movement. Don't seal these; have a structural engineer or foundation specialist assess them.
Foundation Crack Repair cost
| Job | Typical cost |
|---|---|
| Polyurethane injection, per crack | $200–$1,000 |
| Epoxy injection (dry structural cracks), per crack | $300–$800 |
| Several cracks, whole project | $500–$3,000 |
| DIY polyurethane injection kit | $60–$150 |
Got a quote? Check if it's fair
Typical professional price for this job: $200–$1,000
Common questions
Are foundation cracks normal?
Thin vertical cracks in poured concrete are very common and usually come from shrinkage. They matter mainly if they leak. Horizontal cracks, stair-step cracks in block walls and wide or growing cracks are the ones to worry about structurally.
Epoxy or polyurethane: which is better?
Polyurethane foam expands and stays flexible, so it's the usual choice for stopping leaks, even in damp cracks. Epoxy bonds the concrete back together and is used on dry cracks where strength matters.
Can I seal a foundation crack from the inside?
Yes. Low-pressure injection fills the crack through the full wall thickness from inside, which is how most leaking cracks in poured walls are repaired. Surface caulk alone usually fails because water pushes behind it.