Foundation Crack Repair Cost in Ontario: What Drives It
Updated June 2026
There is no flat rate for a foundation crack repair in Ontario, because the price depends on what kind of crack you have. Most cracks are harmless shrinkage that takes a simple injection from inside the basement. A small number are structural and need reinforcement or excavation, which is a much bigger job. The first step is figuring out which one you have, and the honest way to do that is a free site visit and a written quote. This guide walks through what moves the price.
A crack in your foundation looks alarming, and the internet is happy to make it worse. The honest news is that most foundation cracks are not an emergency. They’re shrinkage from the concrete curing, and they take a straightforward fix. A smaller number are real structural problems that cost more to put right. The price of the repair tracks almost entirely to which kind you have, so understanding that is worth more than any number on a web page. Here’s what actually moves it.
Hairline or structural, which is the first question
This is the factor that decides everything else. A thin vertical or diagonal hairline crack is the most common thing we see in a Southern Ontario basement, and it’s almost always shrinkage. Concrete shrinks slightly as it cures, and the wall relieves that stress as a fine crack in its first year or two. It isn’t the house failing. It’s the concrete doing what concrete does.
A structural crack is a different animal. The signs are width, growth, and direction. A crack wider than a coin’s edge, one that keeps opening over the seasons, a horizontal crack, or a stair-step crack running through block all point to pressure or movement rather than simple curing. Those need an engineer’s eye and a real fix. The repair for a harmless hairline and the repair for a structural crack are not the same job and they are not the same price, which is exactly why a contractor who quotes sight-unseen is guessing.
One crack or many
A single crack is a single repair. When a wall shows several cracks, or the same crack pattern repeats around the foundation, that changes both the scope and what the cracks are telling you. A few unrelated shrinkage cracks are still minor work. A run of cracks along one wall, or matching cracks on opposite walls, can mean the soil outside is loading the foundation, and then you’re solving the cause and not just the symptom. Count the cracks before you compare quotes, because the number is part of the job.
Simple injection or structural reinforcement
Most cracks are fixed by injection, and that’s the small end of the work. A two-part resin is injected into the crack so it fills the full thickness of the wall and either bonds it back together or seals it against water. It’s done from inside the basement, in a few hours, with no digging. For the common shrinkage crack, this is the whole repair.
Structural reinforcement is the larger end. When a crack is moving or a wall is bowing, sealing it isn’t enough, because the force that opened it is still there. Carbon-fibre straps or steel bracing across the wall hold it against further movement, and that’s more material, more labour, and sometimes an engineer’s sign-off. The jump in price from injection to reinforcement is the single biggest swing in foundation work, so the real question on any quote is which one your wall actually needs.
Inside or outside, the small fix versus the big one
Where the crack gets fixed is the other big lever. Injecting from inside the basement is the small fix. The crew works against the interior face, the resin fills the crack, the basement stays usable, and there’s no excavation. That’s the route for the great majority of cracks.
Excavation is the big one. To repair a crack from outside, the crew digs down the full height of the foundation to expose the wall, which means moving soil, working around landscaping and walkways, and backfilling and compacting afterward. It’s reserved for the cases the interior fix can’t solve, like a wall that needs exterior waterproofing membrane or a leak that won’t respond to injection. Digging is what turns a half-day basement job into a multi-day excavation, and it’s the reason two foundation quotes can look so far apart. When you compare quotes, the first thing to find is whether the fix is interior or exterior, because that line decides the rest.
Epoxy or polyurethane injection
The two injection resins do different jobs, and a good contractor matches the resin to the crack.
- Epoxy is the structural one. It cures into a rigid, high-strength glue that bonds the two faces of the crack back into a single piece of concrete. It needs a crack that’s dry and dormant, because it sets hard and won’t tolerate water in the crack or future movement. Epoxy is the choice when the point of the repair is to restore strength.
- Polyurethane is the flexible one. It foams and expands as it cures, pushing into a damp crack to seal it against water, and it stays flexible enough to move a little as the wall expands and contracts through the seasons. Polyurethane is the choice when water is the problem and the crack is active or might shift.
In plain terms: a dry crack that needs strength gets epoxy, a wet crack that needs to stop leaking gets polyurethane. A wall that’s leaking during the spring melt is usually a polyurethane job. The material itself is a small part of the cost. Picking the right one is what makes the repair last.
Why the cheap surface smear keeps coming back
There’s a tempting cheap fix that almost always fails: troweling hydraulic cement or caulk over the crack on the inside face. It looks repaired for a season. The problem is that the crack runs through the full thickness of the wall, so water keeps tracking through behind the patch and pops it loose, usually by the next spring. You’ve sealed the face, not the crack.
A real repair fills the crack through the entire wall, which is what injection does and a surface smear can’t. If a quote is cheap because it’s a surface patch, it’s the expensive option in disguise, because you pay again next year when it leaks. Spec to look for on a real injection job is full-depth resin penetration, not a skim of cement on the wall.
How to get a real number for your crack
A foundation crack quote should start with someone actually looking at the crack, because the spread between repairs is enormous and only an inspection tells you which one you’re in. A fair quote names the type of crack, whether the fix is injection or reinforcement, which resin and why, and whether any digging is involved. A one-number quote over the phone can’t know any of that.
The honest way to price a foundation crack is a free site visit and a written quote that holds. Most of the time the news is good and the fix is small. When it isn’t, you want to know that from someone standing in your basement, not from a rate on a web page that was never about your house.
How much does it cost to fix a foundation crack?
It depends entirely on the crack. A single shrinkage crack injected from inside the basement is the small, common job. A structural crack that needs reinforcement, or a leak that has to be chased from outside with excavation, is a much larger one. That's why no honest contractor gives a flat rate over the phone. The size, the number of cracks, the type of repair, and whether the fix is interior or exterior all move the number, so a free site visit and a written quote is the only real answer.
Epoxy or polyurethane injection, which one do I need?
It depends on what the crack is doing. Epoxy is a rigid structural glue. It cures hard and bonds the two sides of a dry, dormant crack back into one piece, so it's used when the crack needs strength restored. Polyurethane is flexible. It foams and expands to seal an active leak and can move slightly with the wall, so it's used when water is the problem and the crack may shift with the seasons. A wet, leaking crack is usually a polyurethane job. A dry structural crack is usually epoxy. The contractor reads the crack and picks.
Are hairline cracks in my foundation normal?
Usually, yes. Thin vertical or diagonal hairline cracks are the most common thing we see, and most of them are shrinkage from the concrete curing in its first year or two. They are not a structural emergency. They matter when they let water in, or when they're wide, growing, horizontal, or stepped through block, because those can point to pressure or movement. If you can watch a hairline crack for a season and it stays put and stays dry, it's almost always cosmetic.
Why does a surface patch on a foundation crack keep failing?
Because a smear of hydraulic cement or caulk on the inside face only seals the surface. The crack runs through the full thickness of the wall, so water still tracks through behind the patch and works it loose, usually by the next spring melt. A proper repair fills the crack through the whole wall, which is what injection does. The cheap surface fix almost always comes back, and you pay twice.