Sika Sikadur-53 UF
A two-component, solvent-free epoxy injection resin engineered to seal cracks that are damp, wet or fully submerged, where conventional resins simply refuse to bond.
What is it?
A two-part, moisture-insensitive epoxy crack-injection resin from Sika, designed to penetrate and structurally seal cracks in concrete and masonry even when they are damp, wet or under water.
Where is it used?
Water-retaining and water-excluding structures, basements, tunnels, bridge decks, foundations, retaining walls and marine works, where cracks stay wet and cannot be dried before repair.
Why use it?
It displaces water and bonds to saturated substrates, so leaking or submerged cracks can be sealed and re-bonded in situ without dewatering, achieving high adhesion where standard dry-crack resins fail.
How is it applied?
Parts A and B are machine or hand mixed 2:1 by weight, allowed a short pre-reaction, then pumped through injection ports into the crack under pressure until the resin runs clean.
About Sika Sikadur-53 UF
Sikadur-53 UF is Sika’s answer to one of the most stubborn problems in concrete repair: a crack that will not stay dry. On any live water-retaining structure, a basement raft, a tunnel invert or a bridge abutment, water keeps seeping into the very crack you are trying to seal. Ordinary epoxy resins bead off a wet surface and cure with poor adhesion, leaving the repair to fail within months. This resin is formulated to do the opposite. It is moisture-insensitive, meaning it chemically tolerates and displaces water at the crack face, wetting out saturated concrete and steel and curing to a hard, shrinkage-free solid that both re-bonds the structure and blocks further ingress.
For Delhi NCR and Pan-India project teams, that translates into fewer shutdowns and faster remediation. Instead of dewatering a wet shaft or waiting weeks for a slab to dry, the contractor can inject through installed ports while water is still present and hand over a monolithic, load-transferring repair. Space Arc Engineering supplies Sikadur-53 UF as an authorised Sika channel partner, along with the injection ports, capping sealer, packers and pumps that make up a complete system. We also advise on where this wet-tolerant grade is genuinely needed versus where a simpler dry-crack resin will do the job at lower cost.
The technical insight
The performance of Sikadur-53 UF comes down to how its epoxy chemistry behaves at a wet interface. Standard epoxies are hydrophobic and cannot form a continuous bond film through a layer of water, so they cure with entrapped moisture and weak, patchy adhesion. This grade uses a modified resin and hardener system that is deliberately moisture-tolerant: on mixing, it is allowed a short pre-reaction period so that the components begin to build molecular weight and can then actively displace water from the substrate as they are injected, wetting the mineral and steel surface directly rather than sitting on a water film. Its relatively high density supports that water-displacement action, pushing water ahead of the resin front as it fills the crack. Because it hardens without shrinkage, the cured resin stays in intimate contact with the crack walls, so the repair transfers load across the crack and seals it against continued water and oxygen ingress, which is what arrests the corrosion cycle in the embedded reinforcement.
Where it is used
- Sealing damp, wet or submerged cracks in reinforced concrete by pressure injection
- Restoring structural continuity across cracks in water-retaining tanks, reservoirs and treatment plants
- Crack repair in basement rafts, retaining walls and diaphragm walls subject to water pressure
- Injection of leaking cracks in tunnels, culverts and underground metro structures
- Bonding and grouting concrete and steel underwater by water displacement
- Sealing cracks in bridge decks, piers and abutments exposed to moisture and de-icing salts
- Repair of foundations and pile caps where the water table cannot be lowered
- Arresting reinforcement corrosion by cutting off water and oxygen paths through cracks
Key advantages
- Bonds and cures reliably on damp, wet and even submerged substrates where standard resins fail
- Displaces water at the crack face for direct adhesion to saturated concrete and steel
- Hardens without shrinkage, keeping the resin in full contact with the crack walls
- Solvent-free formulation with no shrinkage voids and low health and safety burden
- High tensile adhesion to concrete, so the repair restores structural load transfer
- Seals against ongoing water and oxygen ingress, protecting embedded reinforcement
- Allows repair without dewatering, reducing downtime on live water structures
- Backed by Sika’s global injection track record and locally stocked by Space Arc
Limitations & considerations
- Short pot life at Indian site temperatures (around 15 minutes at +30 degrees C), so only mix what can be injected quickly
- Not a low-modulus sealant; unsuitable for cracks that are actively moving or that open and close with thermal or live loads
- Requires trained applicators, proper port spacing, capping sealer and controlled injection pressure to fill cracks fully
- Crack faces must still be clean and free of oil, grease, laitance and loose debris even when wet
- Application and substrate temperature must stay within roughly +5 to +40 degrees C; low temperatures slow cure and hinder injection
- For dry cracks a standard low-viscosity resin is more economical, so wet-tolerance should be a genuine site requirement
Selection & best practice
Success with Sikadur-53 UF is mostly about discipline at the crack. Map and mark the crack, drill or bond surface ports at a spacing suited to the crack width and member thickness, then seal the crack line with a capping sealer and let it cure so injected resin cannot bleed out. Mix full pre-batched units at the correct 2:1 ratio using a slow-speed paddle to avoid entraining air, and for wet or submerged work observe the short pre-reaction wait before injecting so the resin is primed to displace water. Inject from the lowest port upward on vertical cracks (or from one end on horizontal work), moving to the next port only when resin appears clean and contaminant-free at it. Because pot life is short in Indian heat, batch small, keep the pump moving, and stage materials so the previous unit is used before the next is opened. On critical work, take cores afterwards to confirm the resin has actually penetrated the crack depth, and always carry out a preliminary trial to fix ports, pressures and equipment.
Specifications
| Product type | Two-part, solvent-free, moisture-insensitive epoxy injection resin |
| Colour | Part A colourless, Part B reddish-brown, mixed reddish-brown |
| Mixing ratio | Part A : Part B = 2 : 1 by weight |
| Mixed density | ~1.1 kg/l at +27 degrees C |
| Viscosity (mixed) | ~500 mPa.s at +30 degrees C |
| Pot life | ~15 minutes at +30 degrees C (100 g mass) |
| Tensile adhesion strength | >=8 MPa at 14 days (+30 degrees C) |
| Application / substrate temperature | +5 degrees C to +40 degrees C |
| Packaging | 3 kg pre-batched unit (2 kg Part A + 1 kg Part B) |
Industry use cases
Water & Wastewater
Sealing wet cracks in reservoirs, ESRs, clarifiers and treatment tanks without emptying and drying the structure first.
Metro & Tunnels
Injecting leaking cracks in tunnel linings, cut-and-cover boxes and station rafts where water ingress is continuous.
Bridges & Infrastructure
Re-bonding and sealing damp cracks in decks, piers and abutments exposed to rain, groundwater and de-icing salts.
Basements & Foundations
Repairing cracks in rafts, retaining and diaphragm walls under hydrostatic pressure without lowering the water table.
Marine & Ports
Underwater bonding and grouting of concrete and steel elements by water displacement in jetties and coastal works.
Frequently asked questions
How is Sikadur-53 UF different from a normal epoxy crack injection resin?
Can it really be injected into cracks that are still leaking water?
What is the mixing ratio and pot life?
Is it suitable for cracks that keep moving?
What pack size is available and how do I estimate quantity?
Does Space Arc supply the full injection system and support?
How we position Sika Sikadur-53 UF
Reach for Sikadur-53 UF only when wet-crack tolerance is a real requirement. If your cracks are dry and fine, the Sika family offers more economical low-viscosity grades such as Sikadur-52, an ultra-low viscosity resin for injecting dry hairline cracks, while Sikadur-53 FLV suits wider cracks in the same wet-tolerant Sikadur-53 injection line. For gap filling and general epoxy grouting around the same repair, our wider Sika range covers repair mortars and structural grouts. Across brands, Space Arc also stocks equivalent low-viscosity crack-injection resins from Fosroc and Dr. Fixit, so we can match the product to your specification, pump compatibility and budget rather than pushing a single label.
Fosroc Nitofill EPLV — A specifier working to a Fosroc schedule can use Nitofill EPLV as the low-viscosity epoxy crack-injection resin, though for damp or submerged cracks the moisture-insensitive Sikadur-53 UF is the more direct match.
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Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.