This page covers cracks as a water problem. Poured concrete walls crack as they cure and as the house settles; most of those cracks are cosmetically irrelevant until groundwater pressure turns one into a channel.
Reading the crack
- Vertical or near-vertical, narrow, in a poured wall. The classic shrinkage crack. Leaks under pressure, seals well by injection.
- Running from a window or door corner. Stress concentrates at openings. Same treatment when the concern is water.
- Wet at the top, dry at the bottom. Water is entering high, which points at surface drainage rather than the water table.
- Horizontal, or stepping through block joints with bowing. This is a soil-pressure and structural question. It needs an engineer or a structural contractor, not a waterproofing injection.
How injection sealing works
Injection ports are set along the crack at intervals and the face is sealed with a surface paste so material cannot escape. Polyurethane resin is then injected under pressure at the lowest port and worked upward, filling the crack through the full wall thickness. The resin reacts with moisture, expands into the void, and stays flexible enough to tolerate the small seasonal movement concrete undergoes.
Epoxy is the alternative and behaves differently: it is rigid and bonds the two faces together, which is appropriate when the goal is restoring monolithic strength. For a wet crack in an Ohio basement, polyurethane is the more common choice because it tolerates water present during the work.
What happens on inspection
A competent inspection maps every crack, notes width and whether it is currently active, checks the floor edge for separate seepage, and looks outside at grading, downspouts and window wells above the crack location. Exterior water hitting one spot repeatedly is often the reason a specific crack leaks while identical cracks elsewhere stay dry.
When sealing is not the answer
If water is also appearing at the wall-floor joint, or on walls with no cracks, the building is dealing with hydrostatic pressure and the crack is one symptom among several. In that case the durable fix is perimeter drainage, with the crack sealed as part of the same project. Read how cove joint seepage works to tell the two apart.
Cost
Single-crack injection in Ohio typically runs a few hundred dollars to roughly $1,200 depending on wall thickness, crack length and access. That is far below drainage system pricing, which is why an accurate diagnosis is worth the effort — details are on the cost page.