Two distinct chemistries, one diagnosis. Polyurethane expands when water touches it, sealing active leaks in foundation walls and slabs. Epoxy bonds dormant cracks back to monolithic strength. We assess the crack first, then inject the right Sika product to full depth. No guessing. Free estimate.
The concrete is cracked. Water may be flowing through it, or the crack may be stable and dry. The slab may be load-bearing or cosmetic. These conditions determine which Sika chemistry will work. Polyurethane reacts with moisture and expands to fill and seal. Epoxy hardens into a rigid bond that restores structural continuity. Mixing them up wastes material and fails the repair.
Our first step is always diagnosis. We examine the crack for signs of movement, water presence, and structural role. Then we specify the matched Sika product. Polyurethane goes into active wet conditions; epoxy into dormant dry cracks where structural restoration is the goal. The port spacing, injection pressure, and cure time all follow from that choice.
We look for water flow, measure depth and width, check for movement, and determine if the crack is structural or cosmetic. This assessment drives the chemistry choice.
Install ports and seal
Injection ports are placed at intervals along the crack based on Sika's specifications for the chosen product. The crack surface is sealed with paste between ports to contain the injection material.
Inject under pressure
Sika polyurethane or epoxy is pumped through each port in sequence at controlled pressure, filling the crack from bottom to top and ensuring no voids remain.
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 leaking through a crack cannot be sealed with epoxy. The water prevents the epoxy from bonding. Polyurethane is designed for this exact scenario. It reacts with the water in the crack, expanding as it cures, and fills the void while bonding to the wet concrete surface. The leak stops during injection. This is the only chemistry that works in active wet conditions.
Pair polyurethane injection with our basement waterproofing strategy for comprehensive protection, and review Sika floor systems if the basement floor also needs attention.
Polyurethane vs epoxy, 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, Laval
★★★★★
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, Montreal
★★★★★
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, Terrebonne
★★★★★
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, Longueuil
From the blog
Concrete Guides & Articles
Practical reading on planning, finishes and caring for concrete in Laval.
Describe the crack (active or dormant, wet or dry, structural or cosmetic), and we will diagnose, specify the matched Sika product, and quote in writing.
