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Foundation crack repair is the targeted side of basement waterproofing work: sealing the specific cracks where water enters, without excavating the whole house.
Normal Crack or Structural Problem?
| Crack | Usually means | Action |
|---|---|---|
| Thin vertical or slightly diagonal crack in poured concrete | Shrinkage as the concrete cured | Seal if it leaks (polyurethane injection) |
| Hairline crack in the floor slab | Normal shrinkage | Monitor; seal under flooring if moisture shows |
| Crack wider than 1/4 inch, or one side offset | Movement or settlement | Structural engineer evaluation |
| Horizontal crack in a basement wall | Soil pressure pushing the wall | Structural engineer evaluation |
| Stair-step cracks in block walls | Settlement or pressure | Structural engineer evaluation |
| Wall bowing inward | Significant soil pressure | Structural engineer evaluation promptly |
Horizontal cracks, bowing walls and cracks that keep widening are structural concerns. Get an evaluation from a licensed structural engineer before any cosmetic or waterproofing repair.
In newer subdivisions like Overland, Eagle Mountain, photograph and date every crack so it can be raised under the builder warranty.
Crack Width Guide
| Width | Usually | What to do |
|---|---|---|
| Hairline (under 1/16 inch) | Normal shrinkage | Monitor; seal only if it leaks |
| 1/16 to 1/4 inch | Shrinkage or minor movement | Seal if it leaks; mark and monitor for growth |
| Over 1/4 inch, offset, or growing | Movement or settlement | Structural engineer before any repair |
Crack width is only part of the story. Two cracks of the same width can mean very different things if one is a straight vertical line in the middle of a wall and the other runs horizontally along a block course. Direction, offset and whether it is growing matter as much as width.
How to Monitor a Crack
- Mark the endsDraw a short pencil line across each end of the crack and write the date.
- Photograph itHold a tape measure or coin next to the widest point so you can compare later.
- Check each seasonEspecially after spring snowmelt. A crack that grows past your marks or gets wider needs an engineer.
Why Cracks Leak in Spring
A crack can stay dry all year and leak only in March or April. Melting snow saturates the soil against the wall, water pressure builds, and the crack becomes the easiest way in. If your crack only weeps in spring, fixing the grading and window wells on that side can reduce the pressure, and injection seals what is left.
Crack Injection: Epoxy vs. Polyurethane
Polyurethane foam injection
Expands to fill the crack and stays flexible. Best for stopping water in non-structural shrinkage cracks.
Epoxy injection
Cures rigid and bonds the concrete back together. Used when a crack needs structural bonding as well as sealing.
- Clean the crackSurface prepared and injection ports installed along the crack.
- Seal the surfaceA paste seals the crack face so resin cannot escape.
- InjectResin is pumped from the lowest port upward until it fills the full wall thickness.
- FinishPorts are removed and the surface smoothed after curing.
If a crack has already leaked onto carpet or drywall, budget for what mold cleanup will cost alongside the repair.
DIY Crack Kits and Patches
Home polyurethane injection kits ($50 to $100) can work on a small, dry, non-structural crack if you follow the directions carefully. Hydraulic cement smeared over the surface usually fails, because it only seals the face while water keeps moving through the crack behind it. Any crack in the structural rows of the table above is not a DIY job.
New Homes and Builder Warranties
Many builders offer a short workmanship warranty and a longer structural warranty. Read yours for how and when to report problems, and report in writing. Keep dated photos of each crack and any water, and if you are near the end of the first year, a basement check before your builder warranty ends gives you documentation while it still counts.
Cost
| Service | Typical cost |
|---|---|
| Polyurethane or epoxy crack injection | $400 – $1,200 per crack |
| Structural engineer evaluation | $300 – $800 |
| Wall bracing or anchors (structural) | $4,000 – $15,000+ |
A leaking crack behind finished drywall almost always means mold on the back of the wall. Ask about basement mold removal when cracks let water in.
Frequently Asked Questions
Are foundation cracks normal in new Utah homes?
Thin vertical shrinkage cracks are common in poured concrete as it cures. They are usually not structural but can still leak.
Is epoxy or polyurethane better for foundation cracks?
Polyurethane is the usual choice for stopping leaks because it stays flexible. Epoxy is used when the crack also needs structural bonding.
When should I call a structural engineer?
For horizontal cracks, cracks wider than about 1/4 inch, offset cracks, bowing walls or cracks that keep growing.
Why does my foundation crack only leak in spring?
Snowmelt saturates the soil against the wall and builds water pressure, and the crack becomes the easiest way in.