Basement foundation crack repair
Most foundation cracks aren't structural emergencies, but a crack that lets water in will keep leaking until it's sealed properly.
Ask three Elmira homeowners about their foundation cracks and you'll hear about three different walls. A 1990s ranch in Big Flats might have a poured wall with one thin vertical crack under a basement window, where concrete shrank as it cured. A house near the Near Westside might have a fieldstone wall with mortar that has turned to sand in spots. A mid-century Cape in Elmira Heights might have block with a crack that steps up through the joints. Each one leaks for a different reason, and each one gets a different repair.
Is my crack a leak or a warning?
Most thin vertical cracks in poured walls are shrinkage cracks. They let water in but don't mean the wall is failing. These patterns deserve a closer look before anyone reaches for a sealer:
- Cracks that run sideways along the wall, or a wall that leans or bulges inward
- Cracks that climb in steps through block or brick mortar joints
- A gap that's visibly wider at the top or bottom
- A patched crack that has opened up again
- New sticking doors, sloping floors or drywall cracks upstairs at the same time
If you see those, a structural engineer can tell you whether the wall is still moving. Sealing a wall that's being pushed in only hides the problem.
What repairs are used on each kind of wall?
- Poured concrete: crack injection. The crew sets small ports along the crack and pumps in polyurethane foam or epoxy from the inside until it travels through the wall. Polyurethane flexes with small movement and is the usual pick for leaks; epoxy glues the concrete back together and is sometimes chosen where strength is the goal.
- Concrete block: leaking joints are repointed, and because hollow block can fill with water, the cores are often weep-drilled at the bottom so they drain into a perimeter drain.
- Fieldstone and brick: loose mortar is raked out and replaced. The new mortar should be compatible with the old masonry, since mortar that's much harder than the stone or brick can push moisture into the units and wear them out.
Will the city want a permit?
The City of Elmira requires a building permit for work that must conform to New York's Uniform Code, and it lists structural changes among the projects that need one. It also says the contractor is typically the one who obtains it. Routine leak sealing and reinforcing a moving wall may be treated differently, so have the company tell you which applies before work starts. In Horseheads, Southport, Big Flats or any other town or village, ask that municipality's code office.
What affects the price?
- Number of cracks and their total length
- Whether the wall is poured, block, brick or stone
- Paneling, framing, pipes or ducts that have to be moved for access
- Whether bracing, anchors or other structural work is needed
Prices come from the waterproofing company once someone has stood in your basement, checked the walls, the floor joint and the sump, and looked at where roof and yard water goes outside. We don't quote prices, and an honest number can't be given over the phone before anyone has seen the water's path.
Where we connect you with help
Common questions
Can I plug a leaking crack with hydraulic cement?
It may slow a trickle for a while, but it only fills the first inch or so of the crack, and water usually finds a way around. Injection fills the full depth of a poured wall, which is why it tends to hold up better.
When should an engineer look at the wall?
Call one for sideways cracks, bulging or leaning walls, or any crack that's measurably growing. A waterproofer can seal a crack, but only an engineer can tell you whether the wall is stable.
Related services
More background: Chemung County basement water guide.
Water at the base of the wall, a crack that drips, or a sump you don't trust?
Call and a Chemung County waterproofing company will come trace where the water is getting in.