Foundation crack repair
A crack is either a leak to seal or a sign the wall is under pressure. Telling the difference is the first step.
Poured concrete shrinks as it cures, so thin vertical cracks are normal in many basement walls. They become a problem when water comes through or when they keep opening. Cracks that run sideways, step diagonally through block, or show one side shifted past the other are a different matter: they usually mean soil pressure is pushing the wall.
How do I read a crack?
| What you see | Usually means | Typical next step |
|---|---|---|
| Thin vertical crack, dry | Shrinkage | Mark the ends and watch it |
| Vertical crack that leaks | Water path through the wall | Injection |
| Horizontal crack mid-wall | Soil pressure | Inspection for bracing |
| Stair-step crack in block | Wall movement or settling | Inspection; possible bracing or drainage |
| Crack with offset faces | Ongoing movement | Structural evaluation |
How does injection work?
The installer cleans the crack, attaches injection ports along it, seals the face, and pumps resin in from the bottom up until it comes out the next port. Flexible polyurethane is used when the goal is a watertight seal. Rigid epoxy is used when the crack needs to be bonded structurally. The surface seal can be ground off afterward.
Block walls are different
Hollow block walls don't hold injected resin the way solid concrete does, and water can travel through the cores. Leaks in block are usually handled with interior drainage at the base of the wall, repointing open joints, and bracing if the wall has moved.
Fix the cause
Water and frost drive most crack problems. Pair any repair with downspout extensions and grading that sends water away from the house, and if the crack is horizontal, look at bowing wall repair.
Pricing comes from the waterproofing company after it has seen the basement, checked the walls and figured out the water's path in. We don't quote prices, and a phone estimate before anyone has looked is only a ballpark.
Where we connect you with help
Common questions
Should I worry about a hairline crack?
A thin, dry vertical crack in a poured wall is common. Pencil a mark at each end with the date and check it after spring thaw. If it lengthens, widens or leaks, have it inspected.
Will crack injection last?
Done properly on a poured wall that isn't moving, injection is a lasting repair for that crack. It won't stop new cracks or hold back a wall that's being pushed.
Related services
More background: Mankato basement waterproofing guide.
Seepage along the floor, a cracked wall or a sump that can't keep up?
Call and get connected with a waterproofing company that works in the Mankato area.