How Resin Injection Works
Resin injection is a non-invasive repair technique that permanently seals cracks, voids, and cavities in concrete structures. A flowable resin (either epoxy or polyurethane) is injected under controlled pressure into damaged areas, where it hardens to restore strength and prevent further deterioration.
The 7-Step Resin Injection Process
Our specialists inspect the structure to identify cracks, measure their depth and width, and determine if resin injection is suitable. We use moisture testing and structural analysis to ensure the method will be effective.
The surface is thoroughly cleaned to remove dirt, debris, and contaminants. Wire brushing is used along cracks to ensure proper resin adhesion—typically about ½ inch on each side of the crack.
Small holes (typically 19-38mm) are drilled at regular intervals along the crack. Injection ports are installed in these holes, providing access points for the resin application.
A cap seal material is applied over the crack surface, preventing resin from escaping and directing it deeper into the structure. This creates a controlled flow path for optimal penetration.
The two-part resin is mixed according to specifications and loaded into the injection pump. Pressure is gradually applied to fill the crack, starting at the lowest port and working upward to ensure complete penetration.
The resin is left to cure. Initial hardening typically occurs within 6-8 hours, with full strength achieved within 24 hours, depending on ambient temperature and product type.
Once cured, injection ports are removed and access holes are neatly patched. A final inspection confirms structural integrity and proper bond formation.
Types of Injection Resin
| Resin Type | Best For | Key Benefit |
| Epoxy Resin | Structural repairs, load-bearing cracks | Restores 85%+ of original strength |
| Polyurethane | Water-bearing cracks, waterproofing | Expands to seal voids, flexible |
| Polyacrylic | Fine cracks, reinforcement protection | Low viscosity, deep penetration |
Typical Project Timeline
| Phase | Duration | Activity |
| Preparation | 2-4 hours | Assessment, drilling, cleaning, port setup |
| Injection | 1-3 hours | Resin application, pressure monitoring |
| Curing | 24 hours | Full hardening, no foot traffic |
| Finishing | 1-2 hours | Port removal, patching, inspection |
Why Choose Resin Injection?
- Minimal Disruption: No excavation required—occupants can continue working in the space
- Fast Execution: Most projects complete within 1-3 days, versus weeks for traditional methods
- Permanent Solution: Creates watertight, durable seals that prevent future deterioration
- Cost-Effective: Significantly cheaper than demolition, reconstruction, or traditional underpinning
- Structural Restoration: Restores up to 85% of original strength in damaged concrete
- Environmentally Friendly: Non-invasive repair reduces construction waste
Common Applications
Resin injection is ideal for:
- Basement wall cracks and water seepage
- Foundation repair and subsidence stabilisation
- Structural concrete repairs in bridges and buildings
- Industrial floor strengthening
- Water tank and below-grade vault waterproofing
- Post-tensioned concrete repair