Concrete Crack Repair Guide: Is That Crack a Problem?
Tell us where it is and how wide it is. You'll get a straight answer: leave it, fix it yourself, or get it checked.
We earn a commission if you buy through links on this page, at no cost to you. How we choose products
Crack identifier
1. Where is it?
2. How wide is it?
Match it to the line that looks closest, or measure the widest point with a ruler.
Seal it from the inside
A polyurethane injection kit fills the crack all the way through the wall, and it works even when the crack is damp or leaking.
Find your crack by where it is
Each guide starts with how to tell if a crack is serious, then walks through the fix and what it costs.
Fixed it last fall and it's back?
It's rarely bad luck. These are the usual reasons, and each one has a fix.
Read why repairs fail- The crack wasn't cleaned out. Dust and debris keep filler from sticking to the sides.
- A rigid patch on a moving crack. Cracks open in winter and close in summer. Hard patches can't stretch.
- Water got behind it and froze. Each freeze pushes the repair away from the concrete.
- No backer rod in a deep gap. Sealant that's too deep tears instead of flexing.
- The wall was patched only on the inside. Water still enters from the soil side.
What to use, by crack
Pro-grade kits matched to each kind of crack. We earn a commission if you buy through these links, at no cost to you.
| Your crack | What to use | Price | Link |
|---|---|---|---|
| Leaking basement wall | Polyurethane foam injection kit, 10 ft, peel-off surface sealer | $239.95 | View kit |
| Dry vertical wall crack | Polyurethane foam injection kit, 10 ft, epoxy paste surface sealer | $204.95 | View kit |
| Driveway or patio | Urethane slab crack kit with UV stabilization, small | $109.95 | View kit |
| Garage or basement floor | Urethane slab crack kit, medium | $149.95 | View kit |
| Expansion joints | Polyurea control and expansion joint filler kit, 30 ft | $159.95 | View kit |
Prices from Concrete Sealers USA as of November 9, 2026. Not sure which? Use the product chooser or compare epoxy vs polyurethane.
Some cracks aren't a weekend job
A sideways crack in a basement wall, a wall that bows inward, or a gap wider than a quarter inch needs a structural engineer's eyes before anyone sells you a kit. Including us.