Foundation issues are one of the most stressful discoveries an Ontario homeowner can make. Here is a guide to understanding types and appropriate responses.
Types of Foundation Cracks
Vertical cracks: Usually from concrete shrinkage or minor settlement. Manageable with crack injection. Monitor for widening. Horizontal cracks: Structural. Indicate lateral soil pressure. Require immediate engineering assessment — do not delay. Diagonal/stair-step cracks: Indicate differential settlement. Require engineer evaluation. Wide cracks (6mm+): Always get a structural engineer opinion.
Repair Methods
Polyurethane injection: Flexible after curing. Best for active water-leaking poured concrete cracks. Cost: $500-$2,000/crack. Epoxy injection: Rigid repair. Restores structural integrity for inactive cracks. Cost: $400-$1,500/crack. Carbon fibre straps: For bowing block or poured walls with less than 2 inches of movement. $400-$700/strap, typically 6-10 straps/wall.
When to Call a Structural Engineer
Horizontal cracking. Wall bowing or leaning. Stair-step cracking in block foundations. Any crack over 6mm. Cracks that reopen after repair. Foundation movement is progressive — early intervention is always less expensive.
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