Foundation Crack Repair

Most foundation cracks in Connecticut are hairline vertical cracks in poured concrete walls, caused by normal settling and shrinkage as the concrete cured. They leak, sometimes impressively, and they are also the simplest, cheapest thing in waterproofing to fix: a technician injects polyurethane or epoxy into the crack from inside, sealing it through the full thickness of the wall. Typical cost: $500–$1,500 per crack.

Polyurethane vs. epoxy injection

• Polyurethane foam expands to fill the crack and stays flexible, so it tolerates the small seasonal movement every foundation has. It is the standard choice for a leaking crack.
• Epoxy injection bonds the crack rigidly and restores the wall's original strength across the crack. It is the right choice when the crack is stable and structural continuity matters — and the wrong choice for a crack that is still moving, because a rigid repair on a moving wall just cracks again beside the repair.

When a crack is not just a crack

Some cracks mean the wall is moving, and injection alone will not hold. Get a structural evaluation first if you see any of these:

• Stair-step cracks in block walls — the classic sign of differential settlement or lateral pressure.
• Horizontal cracks or bowing walls — lateral soil pressure pushing the wall inward, common where clay soil expands when wet and freezes in winter.
• Cracks that keep reopening after a previous repair, or cracks wider than about a quarter inch.
• Doors and windows sticking on the same side of the house, or floors sloping toward the cracked wall.

Moving walls need bracing — carbon fiber straps, steel I-beams, or wall anchors depending on severity — and that is foundation repair, not crack repair, with a different price range entirely. A contractor who injects a bowing wall and calls it waterproofed has sold you a delay.

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