PU Injection Resin & Grouting Chemicals
Hydrophilic and hydrophobic injection resins that seal cracks, fill voids and stop active water leaks — supplied with the packers and pumps to inject them, from a distributor whose own crews use them daily.
The Only Chemistry That Chases Water Into the Crack.
Coatings and membranes work on surfaces. Injection resins work inside the structure: pumped under pressure through drilled ports, a low-viscosity resin travels along the crack or void, reacts — usually with the very water causing the leak — and cures into a foam or gel that blocks the path permanently.
That is why injection grouting is the specified method for leaking basements, tunnels, lift pits, dams and construction joints, where breaking open the structure is not an option. It installs fast, with minimal disruption, on both new construction and occupied buildings.
- Low viscosity penetrates deep, then expands on contact with moisture
- Cured resin stays flexible — it moves with the structure instead of cracking off
- Durable against moisture, temperature swings and chemicals
- Non-disruptive: suitable for retrofit and live buildings
- Cheaper over the life of the structure than repeated surface repairs
Three Chemistries. Three Different Jobs.
Picking the wrong resin is the most common injection failure. Match the chemistry to the crack, the water and the movement.
Flexible PU Foam Resin
Polyurethane that expands on contact with water into a flexible closed-cell foam. The workhorse for sealing small cracks and stopping live leaks; it adapts to minor structural movement after curing.
Polyacrylic Injection Gel
Hydrophilic, ultra-low-viscosity material that reacts with water to form a flexible gel. First choice for active leaks under hydrostatic pressure and for curtain grouting behind walls and slabs.
MDI-Based PU Resin
Two-component polyurethane forming rigid or flexible foam with high strength, durability and chemical resistance — used where the repair must also be structural, not just watertight.
Which Resin for Which Problem.
Verified, specification-grade products we stock from MC-Bauchemie and Sika — the two brands consultants name most often for injection work.
| Site condition | Resin chemistry | Products we stock |
|---|---|---|
| Active, gushing leak — water entering under pressure | Fast-foaming water-reactive PU | MC-Injekt 2033 · Sika Injection-101 IN |
| Fine cracks and joints that must stay flexible and watertight | Very low-viscosity elastic PU | Sika Injection-201 IN |
| Curtain injection behind walls, rafts, masonry; leaking joints in wet soil | Acrylate hydrogel / polyacrylic gel | MC-Injekt GL-95 |
| Voids and repairs needing strength as well as sealing | Two-component MDI-based PU | Rigid/flexible PU grouts — specified per site |
Where Injection Resins Earn Their Keep.
Handle It Right
Injection is skilled work: resin choice, drilling pattern, injection pressure and curing all affect the result, and uncured resins demand protective gear and ventilation. If you don’t run your own injection crew, our applicators do this every week — see injection grouting services.
Resin Is One-Third of the Job.
You also need packers that hold pressure and a pump that delivers it. We stock all three — and they’re matched to work together.
NRV Grouting Nipples
Dseal non-return-valve packers in metal, plastic and rubber — the one-way ports that stop grout flowing back out.
Packers & nipplesInjection Pumps
High-pressure PU grouting pumps in 2, 3 and 5 HP, plus cement grouting and epoxy machines — for sale with guidance.
Pumps & machineryInjection Grouting Service
Our trained crews arrest the leak for you — material, machinery and workmanship under one accountable name.
Get it donePU Injection Resin FAQs.
Can injection resin really stop an active, flowing leak?
Yes — that is exactly what fast-foaming water-reactive PU resins like MC-Injekt 2033 and Sika Injection-101 IN are made for. The resin reacts with the incoming water itself, foaming and expanding to block the flow path, so the leak’s own water triggers the cure.
Which resin should I use for a leaking basement?
For live seepage, start with a fast-foaming PU; for fine cracks that must stay flexibly sealed, a low-viscosity elastic PU such as Sika Injection-201 IN; for wide-area dampness through walls or rafts, curtain injection with an acrylate gel like MC-Injekt GL-95. Send photos on WhatsApp and we’ll confirm before you order.
What is the difference between PU and epoxy injection?
PU resins are for waterproofing — they foam or gel, stay flexible and tolerate wet, moving cracks. Epoxy injection is for structural repair — it cures rigid and restores monolithic strength, but needs drier conditions. Many jobs use PU first to stop water, then epoxy to restore strength.
How long does an injection repair last?
Cured PU resins are resistant to moisture, temperature and chemicals and are engineered to give decades of performance. The usual causes of early failure are wrong resin selection or poor workmanship — both avoidable with proper specification and a trained crew.
Do I need special equipment to inject resin?
Yes — a high-pressure injection pump and non-return packers. We stock PU grouting pumps (2/3/5 HP) and Dseal NRV nipples, and we train buyers on drilling pattern, pressure and cleanup. Trained application matters: uncured resin requires protective gear and ventilation.