Sika Sikadur-53 FLV
A solvent-free, two-part epoxy injection resin built for the cracks that stay wet — the ones ordinary low-viscosity resins simply cannot hold.
What is it?
A two-part, moisture-insensitive epoxy injection resin (Part A : Part B = 4:1 by weight) that pressure-injects and seals cracks in damp, wet and even submerged concrete.
Where is it used?
Water-retaining and below-grade structures — basements, tanks, reservoirs, STPs, dams, canals and marine works where cracks are actively wet.
Why use it?
Standard injection resins de-bond against moisture. Sikadur-53 FLV cures without shrinkage under water and still develops around 70 N/mm² compressive strength, so the repair holds where water is present.
How is it applied?
Mix Parts A and B for at least 3 minutes to a uniform colour, then pressure-inject through packers into cracks wider than 5 mm using standard injection equipment.
About Sika Sikadur-53 FLV
On a live water-retaining structure, the crack you most need to seal is almost always the one that is weeping. That is precisely where conventional epoxy injection resins fail — moisture on the crack faces stops the resin wetting the substrate, and the bond never forms. Sika engineered Sikadur-53 FLV around that problem. It is a solvent-free, two-part epoxy resin loaded with special fillers that let it be pressure-injected into cracks that are dry, damp, wet or fully submerged, displacing water off the crack faces as it advances rather than being defeated by it. For engineers and applicators working on basements, tanks and marine substructures across India, that single property is what turns an un-fixable leak into a routine repair.
The resin is supplied in pre-batched 5 kg units (4 kg Part A, 1 kg Part B) mixed at a fixed 4:1 ratio by weight, so there is no field guesswork on proportioning. Once combined and injected, it cures without shrinkage and gains structural strength even under water, reaching roughly 70 N/mm² in compression at 14 days and a tensile adhesion above 10 N/mm² — high enough that a pull-off test fails in the parent concrete rather than at the bond line. The trade-off worth stating up front is the filler system: it needs a crack width greater than 5 mm to flow, which makes Sikadur-53 FLV a specialist for wider, water-bearing cracks rather than a hairline-crack resin. Space Arc Engineering supplies and applies it as an authorised Sika channel across Delhi NCR and Pan-India.
The technical insight
The mechanism that sets Sikadur-53 FLV apart is water displacement at the crack face. Ordinary epoxy needs a clean, dry surface to wet out and bond; introduce a film of water and the resin simply sits on top of it, curing into a weak, de-bonded skin. Sikadur-53 FLV is formulated as a moisture-insensitive (hydrophobic) epoxy whose chemistry and filler package let the resin push residual water aside and make intimate contact with the concrete as it is injected under pressure. The special fillers give it enough body — a mixed viscosity around 900 cps at +30°C — to stay in the crack and build against injection pressure rather than washing out, which is exactly why it is rated for cracks wider than 5 mm and not for fine ones. Because the cure reaction is not disrupted by moisture and the system is essentially non-shrink, the resin develops its compressive and adhesive strength on schedule even when the cured mass is permanently under water. The result is a monolithic, load-transferring seal that restores structural continuity across the crack instead of a cosmetic surface fill.
Where it is used
- Sealing live, water-bearing cracks in basement rafts and retaining walls
- Crack injection in water tanks, clear-water reservoirs and sewage treatment plants
- Repairing submerged or tidal-zone cracks in dams, canals and marine structures
- Structural re-bonding of cracks in damp industrial and commercial substructures
- Bonding concrete and steel elements in wet or damp conditions by water displacement
- Sealing leaking cracks in tunnels, shafts and below-grade infrastructure
- Arresting active seepage through cracked lift pits, sumps and underground chambers
- Watertight repair of cracked hydraulic and containment structures
Key advantages
- Injects and cures in damp, wet and fully submerged cracks where standard resins de-bond
- Solvent-free two-part epoxy — no flammable solvents and no solvent entrapment in the crack
- Cures without shrinkage, so the seal stays in full contact with the crack faces
- Develops around 70 N/mm² compressive strength even when cured under water
- Tensile adhesion above 10 N/mm², typically failing in the parent concrete
- Supplied in pre-batched 4:1 units, removing on-site proportioning error
- Restores structural load transfer across the crack, not just a surface seal
- Suited to India’s warm climate with an application window up to +40°C
Limitations & considerations
- Requires a crack width greater than 5 mm — the filler system will not flow into fine or hairline cracks
- Working time is limited: pot life is only about 18 minutes for a 100 g mass at +30°C, so mix in workable batches
- Application is restricted to product temperature +10°C to +40°C and substrate +5°C to +40°C
- Full mixed unit must be used within pot life; partial mixing off the 4:1 ratio compromises cure and strength
- Needs proper injection packers and pressure equipment plus trained applicators — not a caulk-and-brush product
- Shelf life is limited to 12 months from production in sealed, dry storage
Selection & best practice
Start by routing and cleaning the crack and setting mechanical injection packers along its length at spacings suited to the wall thickness. Add the whole of Part B to Part A and mix continuously with a slow-speed drill and paddle for at least 3 minutes until the colour is a uniform reddish-brown with no streaks — under-mixing is the most common cause of soft, uncured resin. Only mix what you can inject inside the roughly 18-minute pot life, and remember that pot life shortens as temperature rises, so plan smaller batches in Indian summer conditions. Inject under pressure from the lowest packer upward, moving to the next port once resin appears, so the resin displaces water and air ahead of it and fills the crack fully. Keep product between +10°C and +40°C and the substrate between +5°C and +40°C. On submerged work, confirm the resin is advancing and not washing out before committing the full sequence. Store unopened units dry, between +5°C and +40°C, and use within the 12-month shelf life.
Specifications
| Type | Two-part, solvent-free, moisture-insensitive epoxy injection resin |
| Chemical base | Epoxy resin with special fillers |
| Mixing ratio | Part A : Part B = 4 : 1 by weight |
| Pot life | ~18 minutes (100 g mass at +30°C) |
| Mixed viscosity | ~900 cps at +30°C |
| Compressive strength | ≥70 N/mm² at 14 days (cured under water at +30°C) |
| Tensile adhesion strength | ≥10 N/mm² at 14 days (concrete failure) |
| Minimum crack width | Greater than 5 mm |
| Packaging | 5 kg pre-batched unit (Part A 4 kg + Part B 1 kg) |
| Shelf life | 12 months from production, sealed and dry at +5°C to +40°C |
Industry use cases
Water & Wastewater
Sealing active cracks in clear-water reservoirs, service tanks and STP structures where the concrete is permanently wet and downtime for drying is not an option.
Infrastructure & Tunnelling
Arresting seepage through cracks in tunnels, shafts and below-grade box structures by injecting directly into damp, water-bearing joints.
Marine & Hydraulic
Repairing submerged and tidal-zone cracks in dams, canals, jetties and sea-facing structures where curing must proceed under water.
Commercial & Industrial Basements
Stopping leaks in basement rafts, retaining walls, lift pits and sumps of high-rise and industrial buildings without dewatering the crack.
Frequently asked questions
Can Sikadur-53 FLV really be injected into a crack that is actively leaking water?
What is the minimum crack width it can be used on?
How is it mixed and what is the working time?
Does it need special equipment to apply?
How strong is the cured repair?
What pack size does it come in and how should it be stored?
How we position Sika Sikadur-53 FLV
Sikadur-53 FLV is the specialist to reach for when the crack is wet and wider than 5 mm — its moisture insensitivity is the whole point. For dry or hairline cracks it is the wrong tool; there, a genuine low-viscosity injection resin is correct, whether from Sika’s own low-viscosity range or, from our other lines, Fosroc Nitofill EPLV. To complete a wet-crack repair, pair it with Sika injection packers and, for the surface crack-capping needed to contain injection pressure, a fast-setting epoxy paste. Where the underlying problem is broad water ingress rather than a discrete crack, treat the structure with a cementitious crystalline or coating system such as Sika’s waterproofing range or Dr. Fixit alternatives from our portfolio, and use Sikadur-53 FLV specifically to seal the structural cracks within that scheme.
Fosroc Nitofill EPLV — Choose the Fosroc option for dry, fine-to-medium structural cracks (from about 0.25 mm) where a very low-viscosity resin is needed — but not for the damp, wet or submerged cracks that Sikadur-53 FLV is specifically built to seal.
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Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.