Foundation cracks, slab splits, and wall fractures demand different repair chemistries. Sika polyurethane expands on water contact to seal active leaks; Sika epoxy bonds dormant cracks for structural restoration. We diagnose the crack type, select the right Sika formulation, and inject to full depth. No guesswork, no failed repairs.
A crack that is actively leaking water cannot be sealed with epoxy. The water blocks the epoxy from bonding to the crack faces. Conversely, polyurethane is designed to react with water and expand, making it ideal for wet, moving cracks but wasteful for dry structural restoration. The chemistry must match the crack condition.
Sika offers both formulations in injection-grade systems with engineered port hardware and controlled-flow equipment. We assess each crack for activity level, moisture presence, and structural role, then specify the matched Sika product. Polyurethane for active leaks; epoxy for dormant structural work.
We examine the crack for signs of movement, water seepage, and structural significance. Active wet cracks get polyurethane; dormant dry cracks get epoxy. This diagnosis determines the entire repair strategy.
Prepare and port
The crack surface is cleaned and sealed with paste between injection ports. Ports are spaced per Sika specifications based on crack width and depth, ensuring material reaches the full depth of the fracture.
Inject under pressure
Sika polyurethane or epoxy is pumped through each port in sequence at controlled pressure. The material fills the crack from bottom to top, displacing air and water, and bonding to both crack faces.
Cure and finish
After cure (fast for polyurethane, slower for epoxy), ports are removed and the surface is sealed. The repair is tested for proper fill and handed off ready for any follow-up work.
For active leaks
When Polyurethane Injection Stops Water
Basement walls and foundation slabs that are currently leaking need polyurethane, not epoxy. The water in the crack triggers the polyurethane to expand and harden, filling the void and stopping the leak. Epoxy cannot bond in the presence of water and will fail on injection. Polyurethane is the only chemistry that works in wet conditions.
After polyurethane injection stops the leak, coordinate with basement waterproofing if the larger wall strategy needs review. See also Sika floor systems for any interior finishing after the leak is sealed.
Chemistry selection, active leaks, port spacing, and structural restoration.
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, Oshawa
★★★★★
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, Toronto
★★★★★
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, Brampton
★★★★★
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, Mississauga
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Describe the crack location and condition (active or dormant, wet or dry, structural or cosmetic), and we will diagnose, specify the matched Sika product, and quote in writing.
