Basement wall crack repair
A single crack that leaks when it rains is one of the more fixable basement problems, if the crack isn't a sign of something structural.
Concrete shrinks as it cures, and most poured foundation walls develop a few thin vertical cracks over the years. Many stay dry. Others open just enough to let water through when the soil outside is saturated. The repair depends on what the wall is made of and whether the crack is still moving.
Which cracks are worth calling about?
- A crack that drips, weeps or leaves a wet stain after rain
- A horizontal crack, or a wall that looks like it's leaning in
- Stair-step cracking through the mortar joints of a block wall
- Cracks that taper, or that you've watched get longer or wider
- Doors or windows upstairs that have started sticking at the same time
The last four can point to soil pressure or settlement, and they need a structural look, possibly by an engineer, before anyone seals them shut.
How are leaking cracks in poured walls fixed?
The usual approach is injection from the inside. The technician cleans the crack, sets injection ports along it, seals the surface, and pumps in polyurethane or epoxy until the material comes out the next port. Polyurethane foams and stays flexible, which suits cracks that only leak. Epoxy cures hard and is more often used when restoring strength across the crack matters. Ask which one the company plans to use, and why.
What about block and stone walls?
Block and fieldstone walls don't respond to injection the way a solid poured wall does, because water moves through hollow cores and mortar joints instead of one clean crack. Repointing, interior drainage, exterior membranes or wall reinforcement are more common answers. A crew that recommends injecting a block wall should be able to explain why it will work on yours.
Questions to ask
- Is this crack structural, or just a leak path?
- What material will you inject, and what's the warranty if it leaks again?
- Does the job need an engineer's letter or a permit?
What affects the price?
- Number and length of cracks
- Wall thickness and how easy the crack is to reach
- Injection material
- Any structural reinforcement or engineering involved
The waterproofing company sets the price, and it should do that only after someone has been in the basement, looked at the walls, floor joint and sump, and walked the outside of the house. We don't quote prices. A figure offered over the phone before anyone has seen the foundation is a rough guess, not a quote.
Where we connect you with help
Common questions
Can I seal a basement crack myself?
Surface patches and caulk often fail because water pushes them off from behind. Injection fills the crack through the wall's thickness. If a crack keeps leaking after a patch, have a pro look.
Does a horizontal crack mean my wall is failing?
Not always, but horizontal cracks and inward bowing often come from soil pressure and should be checked by a foundation specialist or engineer before any waterproofing is done.
Related services
More background: Lycoming County basement water guide.
Wet floor after every storm, or a sump that runs all night?
Call and a Lycoming County waterproofing company will set up a visit.