How do I repair cracks in my concrete foundation in New Brunswick?

Foundation crack repair in New Brunswick depends on the type of crack, whether it is leaking, and whether it is structural or non-structural — and the honest answer is that most foundation cracks in NB warrant a professional assessment before you start applying products. Choosing the wrong repair method for your crack type can seal in problems, give false confidence, or miss an ongoing structural issue.

NB foundations deal with some of Canada's most challenging conditions: 4-5 foot frost depth, spring hydrostatic pressure from snowmelt, saturated clay soils in the Saint John River valley and Fredericton area, and 150+ annual freeze-thaw cycles. These forces cause two broad categories of cracks: non-structural shrinkage cracks (hairline vertical or diagonal cracks from normal concrete curing and minor settlement) and structural cracks (wider cracks, horizontal cracks, or cracks with step displacement indicating active pressure or movement).

Hairline shrinkage cracks — thin vertical or diagonal cracks under 3mm (1/8 inch) wide that are dry and have not changed in years — are extremely common in NB poured concrete foundations and are typically non-structural. These can be sealed from the interior using polyurethane or epoxy injection, which is the most reliable repair method for dry or dormant cracks. Polyurethane is flexible and better for cracks that may experience slight movement; epoxy creates a rigid bond stronger than the surrounding concrete but requires a completely dry crack. Interior crack injection typically costs $500-$1,500 per crack professionally done, and is worthwhile for cracks you want to prevent from becoming water pathways.

Active leaking cracks — cracks that show water infiltration during rain or snowmelt — require a different approach. Hydraulic cement can stop active water infiltration (it sets in under 3 minutes in contact with water), but it is a temporary measure that does not address the exterior water pressure driving the leak. A proper repair for a leaking crack is polyurethane foam injection under pressure, which expands to fill and seal the crack even while wet. This is a professional application.

Horizontal cracks in foundation walls are the most serious category. They indicate lateral soil pressure is bending the wall inward — a structural failure mode that is not repairable with crack fillers. Horizontal cracks in NB foundations require structural assessment and typically structural repair (carbon fibre straps, wall anchors, or underpinning depending on severity).

Exterior waterproofing — excavating down to the footing, repairing the crack from outside, applying a waterproofing membrane, and installing or replacing weeping tile — is the most comprehensive repair for any foundation crack that is leaking or at risk of leaking. It costs $5,000-$15,000 per wall but addresses the root cause rather than managing symptoms from the interior. This is the right call for NB foundations with significant water pressure issues.

For any crack that is wider than 3mm, showing displacement (one side higher than the other), or has appeared suddenly after significant rain or frost thaw events, get a professional structural assessment before attempting any repair. New Brunswick Concrete can match you with experienced foundation repair contractors across the province.