How much does it cost to repair and seal a leaking basement wall crack in Toronto?

Repairing a leaking basement wall crack in Toronto typically costs between $300 and $800 per crack for interior injection, making it one of the more affordable waterproofing repairs available. The price depends on the crack length, the type of injection material used, and whether the crack is actively leaking at the time of repair. Most GTA waterproofing contractors charge a minimum service call fee of around $400 to $500 even for a single small crack, so addressing multiple cracks at once is more cost-effective per repair.

The two main injection methods are epoxy injection and polyurethane injection, and the choice matters. Epoxy injection creates a structural bond — it's essentially gluing the crack back together — and costs $400 to $800 per crack depending on length and accessibility. Epoxy is rigid when cured, which means it's best suited for stable, non-moving cracks in poured concrete walls. Polyurethane injection costs slightly less at $300 to $600 per crack and remains flexible after curing, making it the better choice for cracks that may continue to move slightly with Toronto's freeze-thaw cycles. Polyurethane also expands as it cures, which helps it fill voids and irregular crack paths more completely. For most residential basement cracks in the GTA, polyurethane is the preferred choice because of its flexibility and waterproofing properties.

It's important to understand what you're actually dealing with before choosing a repair method. Hairline cracks in poured concrete foundations are extremely common and often appear within the first few years as the concrete cures and the house settles. These are typically not structural concerns, but they can allow water infiltration — especially during spring thaw when hydrostatic pressure from GTA's clay soils pushes groundwater against the foundation. A single crack that weeps during heavy rain or spring melt is a straightforward repair. However, horizontal cracks, stair-step cracks in block walls, or cracks wider than a quarter inch may indicate structural movement and should be evaluated by a structural engineer before any cosmetic repair is attempted. A structural assessment typically costs $500 to $1,500.

For homes with multiple leaking cracks or recurring issues after injection, the cracks may be symptomatic of a larger waterproofing problem — failed weeping tiles, poor grading, or high water table conditions common in lakefront neighbourhoods like the Beaches, Mimico, and Port Credit. In these cases, a comprehensive waterproofing approach is more cost-effective long-term than chasing individual cracks. Interior perimeter waterproofing systems run $5,000 to $15,000, while exterior waterproofing with membrane application costs $10,000 to $25,000 but addresses the root cause by keeping water away from the foundation wall entirely.

If you're planning to finish your basement, address every visible crack before any framing or drywall goes up. Repairing a crack behind a finished wall means tearing out drywall, insulation, and framing to access it — turning a $500 repair into a $3,000 problem. Most reputable GTA waterproofing contractors offer warranties of 15 to 25 years on crack injection work, so make sure to get the warranty terms in writing.