Most foundation cracks in a Toronto house are not structural, and the ones that are look different from the ones that are not. Knowing which you have is the difference between a $400 injection and a conversation about underpinning.
This page describes what each type looks like, what each costs to fix here, and the specific signs that mean stop reading and call someone.
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Not a brochure. Tell us the basics and we will come back with numbers that reflect your actual foundation.
Read the direction first
Direction tells you more than width does.
Vertical and near-vertical cracks are the most common and usually the least serious. In a poured concrete wall, a vertical crack is frequently a shrinkage crack that appeared as the concrete cured in its first year and has not moved since. It may let water through. It is generally not holding anything up.
Diagonal cracks, typically running from a corner of a window or door opening at roughly 30 to 45 degrees, indicate differential settlement: one part of the foundation has moved relative to another. These are worth a professional opinion. Whether they are active matters more than how wide they are.
Horizontal cracks are the ones to take seriously, particularly with any inward bowing of the wall. A horizontal crack in a block or poured wall generally indicates lateral pressure from the soil, which is a structural condition rather than a cosmetic one.
Stair-step cracks in a block or brick foundation, following the mortar joints, indicate settlement. Whether they matter depends on whether they are still moving.
A horizontal crack with visible inward bowing, a crack you can fit a finger into, or any crack that is visibly wider than it was a few months ago is not something to price-shop. Have a structural engineer look at it.
| Crack type | Usual cause | Usual seriousness | Typical Toronto repair |
|---|---|---|---|
| Vertical, hairline to 3mm | Concrete shrinkage | Low, often water only | Injection, roughly $400 to $900 |
| Vertical, wide or widening | Settlement | Moderate, needs assessment | Depends on cause |
| Diagonal from an opening | Differential settlement | Moderate | Assessment, then repair or underpinning |
| Horizontal | Lateral soil pressure | High | Engineering assessment first |
| Stair-step in block | Settlement | Moderate to high | Assessment, then repair |
| Floor slab cracks | Slab shrinkage or settlement | Usually low | Often cosmetic |
What repair actually costs here
Polyurethane injection, roughly $400 to $900 per crack. The standard treatment for a non-structural crack in a poured wall that is letting water in. Polyurethane is flexible and expands, so it tolerates slight ongoing movement and seals against water. It is a water repair, not a structural one.
Epoxy injection, roughly $500 to $1,200 per crack. Rigid and strong, epoxy bonds the two faces of the crack back together and restores some structural continuity. Because it is rigid, it is the wrong choice where movement is ongoing, and it is normally specified with an understanding of the cause.
Exterior excavation and repair, roughly $2,500 to $6,000 per location. Where the crack needs to be addressed from outside, or where membrane needs to be applied over it, the cost is dominated by the digging.
Carbon fibre straps for bowing walls, roughly $500 to $1,000 per strap, typically several straps. Used to stabilise a wall that is bowing inward, generally on engineering advice.
Underpinning, $500 to $750 per linear foot. When cracking is caused by an inadequate or failing footing rather than by the wall above it, the repair is at the footing.
When cracking means the footing, not the wall
This is the crossover between crack repair and underpinning, and it is worth being clear about because it is where homeowners get sold the wrong thing.
Cracks are a symptom. If the cause is concrete shrinkage, sealing the crack fixes the problem completely. If the cause is that the footing is bearing on soil that is moving, sealing the crack fixes nothing, because the movement continues and the wall cracks again somewhere else.
Signals that the footing rather than the wall is the issue:
- Cracks that reappear after being repaired properly
- Cracks that are visibly progressing over months
- Doors and windows on the floors above that have started to stick or that no longer sit square in their frames
- Sloping floors that were not sloped before
- Separation at the point where a porch, addition or garage meets the main house
- Diagonal cracking at more than one opening on the same wall
Underpinning is the structural remedy when a footing is inadequate, bearing on unsuitable soil, or shallower than adjacent construction. In that situation it is remedial work rather than a basement-height project, though the technique is the same.
How to tell if a crack is still moving
Before spending anything on a crack that is not leaking, establish whether it is active. This costs almost nothing.
- Mark and date it. Draw a pencil line across the crack at several points and write the date. Photograph it with a ruler or a coin in frame for scale.
- Wait through a full season cycle if the situation allows. Toronto's freeze-thaw means a crack that is going to move seasonally will do so between winter and summer.
- Re-photograph from the same position. Same spot, same scale reference.
- A crack monitor is an inexpensive plastic gauge that gives you a numeric reading rather than an impression.
A crack that has not changed in a year is a very different object from one that has opened two millimetres since spring, and no amount of expert opinion substitutes for that observation.
Getting the assessment right
For anything beyond a simple leaking vertical crack, the sequence that protects you is: structural engineer first, contractor second.
An engineer has no product to sell. Their assessment tells you what the cause is and what the remedy needs to achieve, and you then take that to contractors for pricing. Going straight to contractors for opinions on a structural question means asking people who sell repairs whether you need a repair.
For a clearly non-structural leaking crack in a poured wall, this is overkill and an injection specialist can handle it directly.
Common questions
Are foundation cracks normal in Toronto houses?
Vertical shrinkage cracks in poured concrete are extremely common and usually harmless. Horizontal cracks and progressing diagonal cracks are not in that category.
How much does foundation crack repair cost in Toronto?
Polyurethane injection for a typical leaking vertical crack runs about $400 to $900. Epoxy injection runs about $500 to $1,200. Repairs requiring exterior excavation start around $2,500 and rise with depth and access.
Can I inject a crack myself?
Kits exist, and for a hairline non-structural crack some homeowners do it. The risk is not the injection, it is the diagnosis: sealing a crack that is a symptom of movement hides the symptom while the cause continues.
Does a crack mean I need underpinning?
Usually not. Underpinning addresses the footing, and most cracks are not footing problems. It becomes the answer when cracking recurs after proper repair, is actively progressing, or comes with sloping floors and sticking doors above.
Will my insurance cover foundation crack repair?
Gradual settlement and long-term water infiltration are typically excluded from Canadian homeowner policies. Sudden accidental events are treated differently. Read your policy rather than assuming either way.
Should I repair cracks before selling?
A leaking crack shows up in a home inspection and becomes a negotiation. Repairing it properly, with documentation, is generally cheaper than the discount it invites. Repairing it cosmetically to hide it before an inspection is a different thing and it is not something we would help with.
Get a real range
Not a brochure. Tell us the basics and we will come back with numbers that reflect your actual foundation.