Foundation crack injection
Foundation crack injection is the essential solution in Quebec in 2026, especially after the historic drought of the summer of 2025 that exacerbated the movements of clay soils in Montérégie, around Montreal, Laval, Longueuil, Boucherville, Saint-Hyacinthe and on the Rives.
Thousands of homeowners have seen cracks appear or worsen on their concrete walls this fall and winter. Water infiltrates, humidity rises, mold threatens… and the value of the house drops.
Fortunately, more than 95% of basement cracks can be effectively treated with high-pressure polyurethane injection . It’s fast (often a day), clean (from the inside), economical and guaranteed.
Why Cracks Are Exploding Now
The summer of 2025 will be remembered. Prolonged drought, abnormally low levels of the St. Lawrence (up to 1 m below normal), cracking soils, drying wells. In Montérégie and the greater Montreal area, clay soils (present on 70-80% of residential lots) have lost their moisture and contracted violently.
Then came the autumn rains and winter frosts of 2025-2026. The clay swelled suddenly, exerting enormous hydrostatic pressure on the foundation. The result: a marked increase in calls for crack repairs, as reported by experts and media (Radio-Canada, La Presse, Le Droit).
The freeze-thaw cycles, already aggressive in Quebec, have multiplied. The water freezes in the ground (+9% volume), pushes the walls like a hydraulic jack, and then everything contracts when it thaws. Houses from the 1950s and 1980s (and even more recent ones that are poorly drained) are paying the price.
The APCHQ is clear: 60% of Quebec homes over 20 years old have cracks. It recommends a visual inspection every 5 years for these properties. In 2026, with climate extremes intensifying, this figure will only increase if we don’t act.
The good news? Most of these cracks do not require excavation or demolition. High-pressure injection solves 95% of active infiltration cases, with an average 10-year transferable warranty (up to 20 years with some RBQ contractors).
Understanding Foundation Cracks: Types, Causes, and Hazards
Main causes in Quebec:
- Shrinkage-swelling of clay soils (drought 2025 + rainfall)
- Repeated freeze-thaw cycles
- Poor drainage (clogged French drain, poorly prolonged gutters)
- Cold joints, formwork rods, window corners
- Hydrostatic pressure when sewers are saturated
Types of cracks:
- Thin verticals (< 2 mm): often for removal, cosmetics if dry
- Vertical 2-5 mm with humidity: active infiltration
- Stairs or diagonals near windows: differential movement of the floor
- Horizontal or > 5 mm: structural risk (consult a professional engineer)
- Active (“living”) cracks: they change in width according to the seasons
Signs that don’t lie:
- Brown spots, white bloom (salts), musty smell
- Door that jams, floor that tilts slightly
- Sump pump that runs non-stop
- 25¢ coin that goes askew into the crack
Consequences if we wait:
- Mould → respiratory problems (especially children and seniors)
- Resale value loss: $10,000 to $30,000 easily
- Refusal or increase in insurance premiums
- Exploding costs: a small crack repaired in time = $400-900. Wait = full drain or reinforcement at $10,000+
Why injection? Advantages over other methods
Injection is the preferred method in 2026 because it:
- Treats the problem at the source without breaking everything
- Works from the inside (ideal in winter)
- Tracks ground movements (polyurethane)
- Provides an immediate and long-lasting seal
- Costs 5 to 10 times less than excavation
- Done in one day, with no major dust
Compared to:
- Manual repair (sealant): temporary, does not fill deeply
- Outer membrane: invasive, expensive, impossible in winter
- Exterior French drain: excellent in prevention, but does not repair the existing crack
- Wall section replacement: extreme and very expensive
Injection is the perfect “surgical” solution for our Quebec conditions.
Our expertise at your service
You will be able to benefit from all the expertise of Groupe Fissure Expert and see all the difference in quality existing on our repairs!
For any questions or repairs to the cracks in your home, contact one of our experienced technicians at Groupe Fissure Expert inc.
Flexible Polyurethane vs Rigid Epoxy: The Choice That Changes Everything
Here is the clear and updated comparison for 2026:
| Criterion | High-pressure | Rigid epoxy |
|---|---|---|
| Flexibility | Very high (10-400% elongation) | None (0-1%) |
| Ideal | Active cracks, seepage, 2-5 mm, “living” | Dry Structural Cracks, < 3 mm, Reinforcement |
| Water | Excellent (swollen on contact) | Good (must be dry) |
| Freeze-thaw adaptation and clay | Perfect (moves with you) | Limited (risk of new cracks next to it) |
| Duration approx. | 10-20 years | 15-25 years old |
| Average cost per crack | 400-900 | $300-1,000 |
| Working | A few hours | A few hours |
| Typical | 10 years transferable | 10-15 years old |
95% of residential cases → polyurethane (the No. 1 choice in Quebec).
Very large, horizontal or structural crack confirmed by → epoxy engineer or a combination of both.
At Fissure Expert, we evaluate for free and explain why a particular resin is perfect for YOUR crack.
The step-by-step injection process (what really happens in your home)
Step 1: Free Diagnosis (30-60 min) RBQ technician on site. Interior + exterior inspection if possible. Exact measurement of width, depth, humidity, dated photos. Evaluation if injection is sufficient or if structural study is required. Clear and transparent submission on the same day or within 24 hours.
Step 2: Preparation (1-2 hrs)
- Cleaning of the crack (industrial vacuum cleaner + sometimes mild acid to remove dust and milt).
- Drilling of injection ports every 15-20 cm (staggered, at 45° to better reach the bottom of the crack).
- Installation of conical ports (end caps) with surface epoxy to seal.
Step 3: High-pressure injection (2-4 hours depending on the number of cracks)
- We always start from the bottom up to expel the air and water.
- Polyurethane resin injected at high pressure (up to 200-300 bar depending on equipment).
- The product penetrates deeply, swells on contact with residual moisture and fills 100% of the crack (even hairline microcracks).
- Fast curing: 10-30 minutes depending on formulation.
- For epoxy: slower injection, very fluid resin that welds the concrete.
Step 4: Finishing and testing (1 h)
- Port removal, sealing with mortar or sealant.
- Surface smoothing (ready for painting or plastering).
- Hydro test: pressurized water is simulated to confirm zero infiltration.
- Before/after photos.
Indoor vs. Outdoor:
- Interior: 90% of the interventions (no excavation, possible all year round).
- Outside: when easy access and very active crack on the ground side (even more effective against pressure).
Total time: 4 to 8 hours for 1-3 typical cracks. You can stay at home.
Discover our solutions:
- Repair of interior cracks on concrete foundations
- Repair of cold joints or concrete joints
- Repair of concrete pool cracks
- Repair of cracks on concrete slabs
- Repairing cracks in window corners
- Repairing holes in concrete
- Plugging of water infiltration around a formwork rod
- Elevator Pit Repair & Maintenance
- French interior drain
Discounted Costs Quebec 2026
| Intervention | Average | Factors Influencing Price |
|---|---|---|
| Single injection (1 crack) | 400-900 | Length, depth, accessibility |
| Multi-cracks + cold | 800-3,000 | Number, poly/epoxy combo |
| Injection + clogging of formwork rods | 1,200-$2,500 | Complexity |
| Structural study (engineer) | $400-800 (often included) | Severity |
| Vs excavation + outer | $5,000-15,000+ | Avoids this cost altogether |
Factors that vary the price:
- Access (narrow stairs, basement finish)
- Number and length of cracks
- Presence of active water (more suitable polyurethane)
- Geographic Area (Travel)
At Fissure Expert: free quote, transparent pricing, no hidden fees, flexible payment
When to act? Emergency Signs and Long-Term Prevention
Act immediately if:
- Damp or runny water
- Crack that widens from one season to the next
- 25¢ coin in
5 mm or horizontal
- Visible mold or odors
Prevention (actions that save thousands of dollars):
- Gutters cleaned + extended downspouts to a minimum of 2 m
- Slope of the land: 5 cm per meter keeping water away from the house
- Sump pump with battery backup
- Backflow valve on the sewer
- Visual inspection every spring and fall
- Rénoclimat Program: Waterproofing and Drain Subsidies
- Avoid trees within 5 m of the foundation
A well-done injection + good prevention = dry subsoil for 15-20 years.
Is a crack in the foundation still dangerous for my home?
No, not systematically. Many fine (< 2 mm) and dry cracks are cosmetic or due to normal concrete shrinkage. However, if it is wet, allows water to pass through, widens from one season to the next, exceeds 5 mm, is horizontal, stepped or accompanied by a bulging wall, it may indicate an active or structural infiltration problem. In these cases, a professional appraisal is essential to avoid mold, loss of resale value, or worsening.
What is the difference between polyurethane injection and epoxy injection?
- High-pressure polyurethane : Flexible (elongation up to 400%), swells on contact with water, follows the micro-movements of the ground and freeze-thaw. Ideal for active cracks, infiltrations, “living” cracks (2-5 mm), typical Quebec conditions. 100% waterproof, but does not reinforce the structure very much.
- Rigid Epoxy : Welds concrete like reinforced cement, restores structural strength. Perfect for dry, stable structural cracks (< 3 mm), when an engineer confirms a need for reinforcement. Less suitable for cracks that move a lot (risk of new cracks next to it).
Common choice in Quebec : Polyurethane for 95% of residential cases with infiltration; Epoxy or combo for severe cases.
Is injection a permanent solution?
Yes, in the vast majority of cases (more than 95% effective for active infiltrations when well executed). Flexible polyurethane lasts 10-20 years (often guaranteed 10 years transferable), epoxy 15-25 years. It seals throughout, keeps water out, and follows seasonal movements. However, if the root cause (poor drainage, extreme hydrostatic pressure) is not corrected, a new crack can appear elsewhere – hence the importance of prevention.
Can the injection be given in winter in Quebec?
Yes, absolutely – especially from the inside. Polyurethane even works with water in the crack (it reacts with it). No need for excavation, intervention possible 365 days a year. Outdoor work (if crack accessible from the ground) is best from April to October, but indoors is the norm in winter.
Can an outer crack be injected only?
Yes, if the ground is clear and the crack is accessible. External injection is even more effective against hydrostatic pressure (product injected directly at the source). But the interior is sufficient in most cases and is more practical.
If the crack reappears or a new one appears next to it?
Rare with flexible polyurethane (it follows the movements). If this happens, it is often due to an untreated cause (clogged drain, inadequate slope). The warranty covers the work; We come back to adjust. Prevention (gutters, slope of land) avoids this.
Is it covered by home insurance?
Sometimes yes: if sudden infiltration due to a disaster (flooding, backup). Not for normal wear and tear or freeze-thaw. A detailed report is often provided to assist with the claim. Check your policy – many insurers require a certified repair to renew.
Guarantees from Groupe Fissure Expert Fondation
For any inquiries or to obtain the price of repairing your water infiltration, contact the specialists at Groupe Fissure Expert Fondation.