Sequential Polyurethane-Then-Epoxy Crack Repair That Stops Leaks and Bonds Structure.

And the diagnosis decides the order. Polyurethane alone stops the leak but leaves no structural bond, which is fine on a non-structural shrinkage crack and a problem on a settlement-driven crack. Epoxy alone bonds the structure but doesn't seal the leak path under hydraulic pressure, which is fine on a dry crack and a problem on an actively leaking one. Most basement cracks in Nebraska, Iowa, Kansas, and Missouri sit in the middle, leaking under spring hydrostatic load and carrying enough structural meaning that polyurethane alone leaves the wall weaker than it should be. Epp Foundation Repair injects polyurethane first to stop the active leak, then epoxy after the crack dries to bond the structure. Sequential, not either-or. The scope covers diagnosis, a crack monitor if needed, polyurethane injection, epoxy follow-up, and a written warranty. The diagnosis decides which.

This page covers basement-specific water-driven crack repair: the leaking poured-concrete crack, the seeping block joint, the hydrostatic-pressure crack that opens every spring. The companion page at /foundation-repair/foundation-crack-repair/ covers all crack types broadly: settlement cracks, shrinkage cracks, structural cracks across the foundation system, including non-basement contexts like garage slab cracks, exterior wall cracks, and stem wall cracks. If your crack is leaking, this page is the right one. If your crack is dry but you're tracking movement, the foundation-repair crack page is the right one.

A crack that's actively widening is not a crack that gets injected. Injection bonds the crack as it exists today; if the wall is moving, the injection can fail at the same crack or nearby. Epp Foundation Repair installs a glass or plastic crack monitor on any crack where active movement is suspected and re-measures it over time before committing to injection.

Polyurethane and epoxy are often treated as alternatives. The honest answer for most basement cracks is both, in sequence. Polyurethane foam injection is hydrophilic. It foams aggressively in the presence of water, expanding to fill the crack and seal against active hydraulic pressure. The foam cures flexible, which lets the seal absorb minor wall movement without cracking the repair. Specified first when a crack is actively leaking, because it's the only injection product that works against water flow. Epoxy injection is structural. It bonds two faces of a stable, dry crack with a high-strength resin that cures harder than the parent concrete. Specified on a dry, stable crack where structural bond is the goal. The sequence Epp uses on most leaking basement cracks. Step one is polyurethane injection to stop the active leak and seal the crack against further water intrusion. Step two is a cure and dry-out period. Step three is epoxy injection through the same ports, displacing or bonding to the cured polyurethane and adding structural bond across the crack face. The sequential approach addresses both the leak and the structural bond in the same scope of work. ## Carbon Fiber Reinforcement for Block Walls and Active Cracks

Block walls don't behave like poured walls. A horizontal crack in a block wall is rarely a shrinkage crack; it's almost always a lateral pressure crack from expansive clay or hydrostatic load against the exterior. Injection alone on a block-wall horizontal crack solves nothing because the wall is still under load that can reopen the crack. The right tool is carbon fiber strap reinforcement: unidirectional carbon fiber bonded vertically across the crack and epoxied to a prepared block surface, which stabilizes the wall against further bowing or crack propagation. Vertical cracks in block walls are sometimes injectable (if shrinkage or minor settlement) and sometimes not (if active wall movement). Diagnosis decides. Same rule as poured walls. Crack monitor when in doubt.

The single most important honesty on this page. Targeted crack repair works for ISOLATED leaking cracks. One crack, two cracks, occasionally three. When a basement has many leaking cracks, or when the seepage is wall-wide rather than crack-specific, or when the cove joint is leaking along the full perimeter, the right tool is full interior waterproofing. That means drain tile at the cove, sump pump sized to contributing area, and a wall vapor barrier, not crack-by-crack injection. Epp Foundation Repair will say so on the inspection. Injecting a hairline cosmetic shrinkage crack is also the wrong scope. Concrete shrinks as it cures, which on a long poured wall often produces a hairline crack. Hairline cracks this narrow are rarely water entry points, because surface tension holds the water out. Epp will tell you. Injecting a widening crack is also the wrong scope: if the crack is moving, the repair fails. Reinforcement (carbon fiber, wall anchor) or settlement work (pier) comes first. Injection is the last step after the movement source is addressed.

Crack inspection and monitor. Visual inspection notes crack width (with a crack gauge or feeler), crack length, leak rate during recent rain or active leak, surrounding wall condition, and any indicators of movement (offset, displacement, secondary cracking). A glass or plastic crack monitor is installed if movement is suspected and re-measured over time before committing. Surface prep and port installation. Crack is cleaned with a wire brush and compressed air to remove loose concrete and prior caulk. Mechanical injection ports (plastic nipples) are surface-mounted along the crack at a spacing set by crack width. The crack between ports is sealed with a surface paste (fast-set epoxy) to contain the injection material. Polyurethane injection to stop the leak. Polyurethane resin is injected through the lowest port first, working upward as foam emerges from the next port up. Foam expansion fills the crack from the back of the wall to the front, sealing against any active hydraulic pressure. Each port is sealed off as the next one begins to bleed. Cure and re-inspect. After a cure period, the wall is re-inspected after the next significant rain event to confirm the leak is stopped. If any port shows residual seepage, the port is re-injected. Epoxy injection for structural bond. Same port array is used to inject epoxy resin, displacing or bonding to the cured polyurethane and creating a continuous structural bond across the crack face. Injection works lowest-port-up. Port removal and finish. Surface ports are snapped or ground off at the wall plane. Surface paste is ground flush. Wall is left ready for paint, drywall, or finish framing, depending on the homeowner's plan. Written warranty documents the crack location, injection sequence, and materials used.

Eastern Nebraska and western Iowa loess soil over glacial till applies hydrostatic load against basement walls in spring when the perched water table rises. That load opens hairline shrinkage cracks in poured concrete walls just enough to admit water. Polyurethane is the right first injection here because it works under active hydraulic load. Kansas and Missouri expansive clay applies lateral pressure against block walls that can open horizontal courses. That's carbon fiber strap territory, not injection territory. Across the four-state region, repeated freeze-thaw cycles each winter open and close existing cracks, which is why epoxy bond (which cures rigid) is paired with polyurethane (which cures flexible). The polyurethane absorbs the freeze-thaw movement that would otherwise crack the epoxy.

Epp injects cracks and installs carbon fiber. Three adjacent scopes Epp does not perform. Exterior excavation to install a membrane on the outside of a single crack. That's exterior waterproofing scope, covered on a separate page, and rarely the right call when interior injection works. Surface caulking of cosmetic hairline cracks. Settlement repair (pier installation) as part of a crack scope. If the crack indicates settlement, the pier work is the primary scope and the crack repair follows; Epp quotes both but separates the scopes so the homeowner understands which work is doing which job.

Customized Repair Estimate after on-site inspection reflects your scope. Epp Foundation Repair is BBB A+ accredited and a BBB Integrity Award winner. When the crack count justifies it, Epp recommends full basement waterproofing instead of per-crack repair.