Foundation Crack Repair

How we diagnose and repair your foundation crack

In Quebec, foundation cracks appear mainly because of differential soil settlement, freeze-thaw cycles, hydrostatic pressure from a failing French drain, vibration from nearby work, and the age of the concrete itself. Homes built before 1980 and houses on clay soils, common around Mascouche and Joliette, are at higher risk. A good diagnosis starts with identifying the cause, not just the visible crack. A hairline that keeps coming back in the same spot after a surface seal almost always points to an exterior drainage problem, not a defect in the concrete itself.

Not every crack carries the same level of risk. Hairline cracks under one millimetre are mostly cosmetic but should be monitored. Vertical cracks of one to five millimetres usually repair very cleanly by injection. Horizontal cracks are a warning sign because they reveal lateral pressure pushing on the foundation wall. Staircase cracks, which follow the joints in a block wall, and full structural cracks must be taken seriously and require quick intervention. Five signs always warrant a professional inspection: width greater than 5 mm, visible progression over four weeks, staircase branching, water seepage, or a noticeable level shift in the floor above.

Our repair methods come down to four proven approaches. Epoxy injection is for dry, stable structural cracks because it restores the mechanical strength of the concrete and literally welds both faces of the crack back together. Polyurethane injection is the preferred choice for active or weeping cracks: the product expands on contact with water, seals the crack, and tolerates small structural movements, which matters for a house that keeps shifting slightly with the seasons. Surface sealing applies to non-structural cracks, often for cosmetic reasons or to block a single localized leak. Interior coating becomes necessary when a crack runs through a wall below grade and exterior waterproofing isn't accessible, for instance under a deck or an attached garage.

Our four-step process frames every job. Step one, the on-site inspection, free and no-pressure, where our technicians document each crack with photos, measurements, and notes. Step two, a written diagnosis with the recommended method and a detailed estimate, so you can compare everything transparently. Step three, the repair itself, generally a half-day to two days depending on complexity and the total length of crack to treat. Step four, the written warranty and a six-month follow-up to confirm the seal holds, with a free return visit if any seepage reappears.

Why not wait? An ignored crack leads to basement water infiltration, mould growth, progressive structural damage, and a drop in property value that can even qualify as a hidden defect at resale. The faster the intervention, the more targeted and affordable it stays. Imperméabilisation GSV usually comes out within five business days across Lanaudière, and cracks that are actively letting water through are treated as a priority.

Cost is one of the first questions every homeowner asks, and the honest answer is that it varies. The price of a foundation crack repair depends on the type of crack, its length, whether interior or exterior access is required, and the chosen method. A single vertical interior injection of about one metre sits in an accessible range. Multiple cracks, exterior excavation, or interior coating along a long wall section all push the price up. We give you a firm, itemized written estimate after the on-site inspection, with no obligation to proceed. If a related issue, such as a clogged French drain or exterior waterproofing failure, is contributing to the cracking, we'll flag it so you can decide whether to address the root cause at the same time.