Foundation cracks, slab fissures, and wall fractures demand the right chemistry. Sika polyurethane flows into active wet cracks and expands on water contact. Sika epoxy bonds dormant dry cracks back to monolithic strength. We diagnose each crack, select the matched Sika formulation, and inject to full depth. No guesswork, no failed repairs.
A crack that is actively leaking cannot accept epoxy. Water present in the fissure will displace the epoxy and prevent adhesion to the concrete faces. Polyurethane, by contrast, reacts with water as part of its cure mechanism. It expands inside the crack, fills voids, and bonds to wet surfaces. For any active seepage or moisture, polyurethane is the only viable choice.
Epoxy enters the picture when the crack is dormant and dry. It cures to a rigid bond that restores the two sides of the slab to structural unity. Test cores often show the injected zone stronger than the surrounding concrete. Epoxy is the structural repair tool; polyurethane is the leak-stopping tool.
We assess the crack condition on-site (active or dormant, wet or dry, load-bearing or cosmetic), then specify the Sika product that matches. See our foundation crack repair page for residential applications, and explore Sika waterproofing for broader moisture control strategies. Our Sika repair services handle surface restoration after injection.
Recent work
The injection sequence
How Sika Crack Injection Gets Done
Assess the crack
We examine the crack for signs of active water movement, measure depth and width, and determine whether it carries structural load. This assessment drives the chemistry choice.
Prepare and port
The crack surface is cleaned and sealed with a paste barrier between injection ports. Ports are spaced according to Sika specifications for the chosen product and crack geometry.
Inject under pressure
Sika polyurethane or epoxy is pumped through each port in sequence at controlled pressure, allowing the material to penetrate the full depth of the crack before advancing.
Cure and finish
The material cures (polyurethane fast, epoxy over several days). Ports are removed, the surface is sealed, and the repair is tested for completeness before handoff.
For active leaks
Why Polyurethane Injection Stops Water
A basement wall seeping water through a crack cannot wait for epoxy to cure. Polyurethane reacts with the moisture in the crack, expanding as it cures and filling every void. The expansion pressure forces the material into hairline branches and micro-fissures that a non-reactive product would miss. The result is a water-tight seal that holds through freeze-thaw cycles and seasonal pressure changes.
Polyurethane injection is a single-visit repair for most residential leaks. The material cures in hours, and the wall is dry. Pair this with Sika waterproofing on the exterior if the broader foundation strategy requires it. For structural follow-up, see basement waterproofing options.
Chemistry selection, active leaks, port spacing, structural restoration, and timeline.
Polyurethane for active wet cracks (it reacts with water to expand and bond), epoxy for dormant dry cracks that need structural restoration (it bonds the crack sides permanently). The wrong chemistry fails immediately.
Yes, polyurethane is specifically designed for this. The water in the crack triggers the polyurethane reaction, the material expands to fill the crack, and the leak stops.
Yes, with epoxy. Properly injected epoxy restores the two sides of the crack to monolithic strength. The crack itself becomes structurally stronger than the surrounding concrete in many cases.
Based on crack width, depth, and the chosen chemistry's flow characteristics. Sika specifies port spacing per product; we follow the spec so material reaches full-depth without gaps.
Most residential crack injections are a single-visit job, a few hours from port install through cure. Large structural projects with many cracks stretch over days. The schedule is in the quote.
Polyurethane injection on an actively leaking basement crack. Water stopped during injection, dry for two years since. The right chemistry made the difference.
Q. Y5
Property Owner, Pittsburgh
★★★★★
Epoxy injection for structural restoration on a foundation crack. Test cores after cure showed the crack zone stronger than surrounding concrete. Real structural repair.
Y. Y5
Engineer, Aliquippa
★★★★★
Multiple cracks across a structure, each classified properly and injected with the right chemistry. The discipline of product-per-crack-condition is rare and showed in the result.
Z. Y5
GC, Monroeville
★★★★★
They diagnosed an injection that another contractor had failed on. Used the right Sika polyurethane this time; held through three winters. Crack chemistry matters.
X. Y5
Builder, Mckeesport
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