Epoxy and Polyurethane Crack Injection: Sealing Foundation Cracks From the Inside

Epoxy cures into a rigid, high-strength material and is used to bond a dry, non-moving crack in a poured-concrete wall back together. Polyurethane cures into a flexible foam that expands when it meets moisture, which makes it well suited to sealing a damp or actively leaking crack and to handling minor movement. Because so many Carolina cracks are leaking when we see them, polyurethane is frequently the better fit, but we confirm which material suits your crack during the inspection.

For a narrow crack in a poured-concrete wall that is letting groundwater seep through, injection is a direct way to seal that path, and polyurethane in particular is designed to chase and stop water inside the crack. What it does not do is lower the water pressure or change the soil conditions outside the wall. If water is also finding other routes in, or if the wall is a concrete block rather than poured concrete, a different waterproofing approach may be needed, which we assess before recommending injection.

Not on its own. Injection seals the crack you can see, but it does not change the force that opened it. In the Piedmont, that force is often clay soil swelling and shrinking against the wall through wet and dry seasons. In coastal areas it is often a high water table pressing on the wall. If the crack is from active movement or foundation settlement, we treat injection as one part of a plan rather than the whole answer and may recommend a structural evaluation so the underlying cause is addressed.

No, and this is where an honest inspection matters. Injection is well suited to many narrow cracks in poured-concrete walls. It is not the right tool for every situation, such as cracks in concrete block walls, cracks that are actively widening from significant structural movement, or cases where the real issue is settlement or wall movement that needs to be stabilized first. We will tell you plainly when injection is not appropriate and what we would recommend instead.

Cost depends on the length and width of the crack, how many cracks are involved, whether epoxy or polyurethane is used, the condition and access of the wall, and whether any structural or waterproofing work is recommended alongside the injection. Because those factors vary from one foundation to the next, we provide pricing after a no-pressure inspection rather than posting a flat number online. The inspection is how we give you an accurate quote for your specific situation.

In most cases, yes. Injection is performed from inside the wall by setting ports along the crack and filling it with resin, so it generally does not require excavating around the outside of the foundation to reach the crack. For a suitable poured-concrete crack, that typically means a less disruptive repair. Whether it is the right approach for your wall depends on the crack and the cause, which is what the inspection confirms.

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A local specialist will inspect your foundation, walk you through the findings, and send a clear estimate. no cost, no pressure.