Calgary foundation services
Foundation Crack Repair in Calgary
I have a crack in my foundation. Can it be repaired, and how?
Most foundation cracks in Calgary homes can be repaired without rebuilding the wall. Narrow vertical cracks are usually sealed by injecting polyurethane or epoxy from inside, typically in a few hours. Horizontal cracks, cracks wider than about 6mm, and cracks where one side has moved out of line with the other are a different category: they point to a wall under load, and sealing them without addressing the load means they reopen.
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Concrete cracks. A poured foundation shrinks as it cures and almost every Calgary basement has hairline cracks somewhere, most of which will never do anything. The useful question is not whether you have a crack but which kind you have, because the answer separates a few hundred dollars from a five-figure excavation.
Three characteristics carry nearly all of the diagnostic weight: the direction the crack runs, whether the two sides are still flush with each other, and whether it is changing. Everything below is organised around those three.
What you are probably seeing
- A vertical or near-vertical crack in a poured concrete wall, often starting at a window or corner
- A hairline crack that stays dry most of the year and weeps during spring melt
- A stair-step crack following the mortar joints in a block or brick foundation
- White chalky deposits on the wall beside the crack, left behind as water evaporates
- A crack you can see daylight or feel airflow through
Why foundation cracks form
Shrinkage is the most common and least alarming cause. Concrete loses volume as it cures over the first year, and it relieves that stress by cracking, usually vertically and usually near an opening such as a window or a service penetration. These cracks are narrow, stable and do not indicate anything is wrong with the structure.
Soil pressure is the more serious cause. Clay-rich soil expands as it takes on water and presses inward against the basement wall. When that pressure exceeds what the wall can resist, the wall cracks horizontally, typically around mid-height where the bending is greatest. This is a load problem, not a concrete problem.
Differential settlement produces a third pattern. If the ground under one part of the footing loses support while the rest holds, the foundation is effectively bent, and it cracks on a diagonal running away from the settled corner. Doors and windows in the affected part of the house usually start sticking around the same time.
Freeze-thaw cycling does not usually create the first crack, but it reliably widens one that already exists. Water sits in the crack, freezes, expands, and levers the two faces apart a little further each time.
Repair methods and what each one suits
There is no single best method. Each of these solves a specific problem, and using the wrong one is the most common reason a repaired crack comes back.
Polyurethane injection
A flexible resin is injected into the crack under pressure, where it expands on contact with water and fills the full depth of the wall. Because it stays flexible after curing, it tolerates the small seasonal movement that Calgary's freeze-thaw cycling imposes.
Best suited to: Actively leaking cracks, and any crack in a wall that still moves seasonally.
Epoxy injection
A rigid resin that bonds the two faces of the crack back together, restoring some of the wall's original strength across the break. It cures hard, so it will crack again if the wall keeps moving.
Best suited to: Dry, stable, non-structural cracks where restoring the bond matters.
Carbon fibre reinforcement
Strips of carbon fibre are bonded across the crack and up the wall to resist further inward movement. This restrains a wall; it does not push it back or remove the pressure causing the problem.
Best suited to: Walls with modest bowing where an engineer has confirmed restraint is sufficient.
Exterior excavation and membrane
The soil is dug away down to the footing, the crack is repaired from the outside, and a waterproof membrane and drainage layer are applied to the wall face before backfilling. It addresses the crack and the water path at once.
Best suited to: Repeat failures, badly deteriorated walls, and cases where drainage is the real problem.
What a crack repair visit usually involves
Inspection and measurement
The crack is measured for width and checked for displacement, meaning whether one side sits proud of the other. Direction, length and the position on the wall are recorded, along with any related signs elsewhere in the house.
Cause diagnosis
A repair that ignores the cause fails. This step should produce an explanation of why the crack formed, not just a price to fill it. If nobody offers you one, ask.
Surface preparation
Injection ports are fixed along the crack at intervals and the surface between them is sealed so the resin travels into the wall rather than back out at you.
Injection
Resin is injected from the lowest port upward until it appears at the next port, confirming the void is filled at that depth. The process repeats up the crack.
Cure and finish
The ports and surface seal are removed after curing. Most interior injection repairs are completed in a single visit.
Cost and Calgary conditions
What drives the price
Published Alberta figures for a straightforward interior injection run from a few hundred dollars for a hairline crack to several thousand where the crack is structural. Calgary sources disagree sharply on the same job, and the exterior figures sit an order of magnitude higher.
Why this behaves differently in Calgary
Calgary's roughly 16 freeze-thaw cycles between December and February are the reason flexible polyurethane is so often specified here over rigid epoxy. A wall that crosses zero repeatedly all winter is a wall that keeps moving slightly, and a rigid repair in a moving wall is a repair with a short life.
The other Calgary-specific consideration is the spring pattern. A crack that has been dry since October and starts weeping in March is behaving normally for this city: snowmelt is arriving faster than still-frozen ground can absorb it. That timing points at drainage and grading before it points at the wall.
When to get someone in
Worth acting on now
- Get this looked at: The crack runs horizontally across the wall
- Get this looked at: One side of the crack sits proud of the other, so the wall faces no longer line up
- Get this looked at: The crack is wider than about 6mm, roughly the width of a pencil
- Get this looked at: The crack has visibly widened over weeks rather than years
- Get this looked at: Water is entering through it while you read this
Reasonable to monitor
- A narrow vertical crack that has not changed in years
- Hairline cracking near a basement window that stays dry
- Fine surface crazing with no depth to it
Questions people actually ask
Can a cracked foundation be repaired?
Yes, in the large majority of cases. Narrow and vertical cracks are routinely sealed by injection from inside. Cracks caused by ongoing soil pressure or settlement need the underlying load or support problem addressed as well, but even then full foundation replacement is uncommon and is a last resort rather than a standard remedy.
Can a leaking foundation crack be repaired from the inside?
Often, yes. Polyurethane injection fills the crack through the full thickness of the wall and stops water travelling through it, and it is done from inside without excavation. Interior repair does not change what is happening in the soil outside, so where the underlying issue is drainage or hydrostatic pressure, an interior repair treats the symptom and the drainage still needs attention.
How long does foundation crack repair take?
A single interior injection repair is usually a few hours and is generally completed in one visit. Exterior excavation repair is a multi-day job because the digging, repair, curing and backfilling each take time, and it depends on weather and machine access.
How much does it cost to patch a foundation crack in Calgary?
Published Alberta ranges start around $250 to $800 for a minor hairline crack and $500 to $1,500 for a standard vertical crack, rising to $1,500 and above where the crack is structural. Calgary sources disagree materially on interior repair, with one publishing $2,500 to $10,000 for work another prices per crack in the hundreds, because the same words cover different scopes. Our cost page sets the published figures side by side with their sources.
Is a vertical foundation crack serious?
Usually not, on its own. Vertical cracks are most often shrinkage from the concrete curing. They become worth investigating when they are wider than about 6mm, when the two sides no longer line up, when they are actively growing, or when they are letting water in.
Should I just fill the crack myself?
Surface fillers from a hardware store seal the face of a crack but do not fill its depth, so water continues to travel through the wall behind the patch and the repair typically fails within a season or two. The bigger risk is that filling a crack hides whether it is still moving, which is the single most useful piece of diagnostic information you have.
Get this looked at by a Calgary contractor
Tell us what you are seeing and roughly where you are. We pass it to an independent Calgary foundation contractor who contacts you directly.
We are a referral service, not a contractor. Your request goes to an independent Calgary foundation company.