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. Diagnosis, 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 fails within 90 to 180 days at the same crack or 6 to 18 inches over. Epp Foundation Repair installs a glass or plastic crack monitor on any crack where active movement is suspected and re-measures at 30, 60, and 90 days before committing to injection.

Polyurethane and epoxy are often treated as alternatives. Polyurethane shops emphasize leak-stopping; epoxy shops emphasize structural bond. 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 4 to 8 times its liquid volume 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. Tensile strength of cured injection epoxy is roughly 7,000 to 12,000 psi, well above the 3,000 to 5,000 psi of typical foundation concrete. Specified on a dry, stable crack where structural bond is the goal. The sequence Epp uses on most leaking basement cracks. Step one. Polyurethane injection to stop the active leak and seal the crack against further water intrusion. Step two. 7 to 14 day cure and dry-out period. Step three. Epoxy injection through the same ports, displacing or bonding to the cured polyurethane and adding structural bond across the crack face. The sequential approach gives the homeowner a dry crack and a structurally bonded crack from 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. Usually at the third or fourth course from the top. 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 will reopen the crack within 12 to 24 months. The right tool is carbon fiber strap reinforcement. 12-inch-wide unidirectional carbon fiber bonded vertically across the crack at 4 to 8 foot spacing, epoxied to a prepared block surface. Each strap carries roughly 80,000 pounds of tensile load and prevents further wall 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 5 or more cracks leaking, 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. Drain tile at the cove, sump pump sized to contributing area, wall vapor barrier. Not crack-by-crack injection. The math shifts at 4 or 5 cracks, and Epp Foundation Repair will say so on the inspection. Also wrong scope. Injecting a hairline cosmetic shrinkage crack. Concrete shrinks roughly 0.05% as it cures, which on a 30-foot wall produces a hairline crack every 8 to 12 feet. These are not water entry points unless they're 0.020 inch or wider. Narrower than that, surface tension holds the water out. Epp will tell you. And wrong scope. Injecting a widening crack. 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. Re-measured at 30, 60, and 90 days 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. 1/4-inch plastic nipples. Are surface-mounted along the crack at 6 to 12 inch spacing, depending on crack width. The crack between ports is sealed with a surface paste (fast-set epoxy) to contain the injection material. Polyurethane injection. Leak stop. Polyurethane resin is injected through the lowest port first, working upward as foam emerges from the next port up. Foam expansion (4 to 8 times liquid volume) 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. 7 to 14 day cure period. 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. 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. Epoxy cures at 60 to 80°F for 24 to 48 hours to full bond strength. 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 for 60 to 90 days each spring when the perched water table sits 4 to 8 feet below grade. That load opens hairline shrinkage cracks in poured concrete walls just enough to admit water. Typical crack width during peak load is 0.015 to 0.030 inch, well above the 0.020-inch threshold where surface tension fails. Polyurethane is the right first injection here because it works under active hydraulic load. Kansas and Missouri expansive clay with plasticity index above 30 applies lateral pressure against block walls that opens horizontal courses at the third or fourth row from the top. That's carbon fiber strap territory, not injection territory. Across the four-state region, 50-plus freeze-thaw cycles per winter open and close existing cracks 0.005 to 0.010 inch per cycle, 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 in 3 to 5 winters.

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.

Basement crack repair from Epp Foundation Repair runs across these anchored components. Customized Repair Estimate after on-site inspection reflects your scope. Epp Foundation Repair is BBB A+ accredited and a two-time BBB Integrity Award winner (2011 and 2016). Recognition tied directly to the practice of installing crack monitors before injecting, declining to inject hairline shrinkage cracks, and shifting homeowners from per-crack pricing to full basement waterproofing when the crack count justifies it.