Fosroc Nitoprime 57
A damp-tolerant, two-component water-based epoxy primer and concrete bonding agent that keeps protective coatings sticking even when the substrate refuses to dry out.
What is it?
A two-component, water-based epoxy resin primer from Fosroc that bonds protective coatings to damp or freshly cured concrete, and doubles as an adhesive between hardened and new concrete or mortar.
Where is it used?
Damp concrete floors, basements, water-retaining structures, sewage and effluent works, and repair interfaces where the substrate cannot be fully dried before coating or overlaying.
Why use it?
It tolerates moisture that defeats conventional solvent-based primers, is low-odour and water-thinnable, and resists dilute acids, salts, mineral oils and aliphatic hydrocarbons once cured.
How is it applied?
Mix base and hardener in the supplied ratio, then brush, roller or squeegee a thin even film onto a clean, sound, saturated-surface-dry substrate and apply the coating or fresh concrete within the overcoat window.
About Fosroc Nitoprime 57
Fosroc Nitoprime 57 is a two-component, water-based epoxy resin primer engineered for the one problem that derails a large share of coating and overlay failures in India: a substrate that simply will not dry. On most Indian projects, basement rafts, water-retaining tanks, STP and ETP structures, podium slabs and monsoon-soaked floors hold residual moisture for weeks. Conventional solvent-based epoxy primers blush, disbond or trap vapour on such surfaces. Nitoprime 57 is formulated specifically so it can be applied to wet or damp concrete and still develop a sound bond, making it the bridge between a green or moist substrate and the protective or decorative system that follows.\n\nThe product has two distinct roles. As a primer, it seals and keys damp concrete so that subsequent Fosroc coatings, screeds and overlays adhere reliably. As an adhesive, it serves as a bonding agent between hardened concrete and fresh concrete or mortar, which is exactly the interface a repair contractor faces when patching spalled slabs, building up levels, or casting new sections against old. Because it is water-based, it is low-odour and water-thinnable for cleaning, which matters when working inside enclosed tanks, basements and occupied buildings where solvent fumes are a safety and nuisance issue.\n\nOnce cured, the primer film is chemically robust. Fosroc states it resists attack from diluted acids, salt solutions, mineral oils and acyclic (aliphatic) hydrocarbons, so it is a sensible choice at the base of corrosion-protection build-ups in industrial, marine-influenced and effluent environments rather than only in clean, dry interiors. For a distributor like Space Arc Engineering, Nitoprime 57 is the part of a specification that quietly protects everything above it: get the damp-tolerant primer right and the topcoat, screed or repair concrete behaves; get it wrong on a moist slab and the whole system can lift.\n\nIt is worth being precise about what Nitoprime 57 is not. It is a thin-film primer and bonding agent, not a damp-proof membrane, not a structural injection resin, and not a finished wearing surface. It manages the moisture-sensitive bond line; it does not stop bulk hydrostatic water ingress. Specifiers should pair it with the correct membrane, coating or repair mortar for the actual exposure rather than treating the primer as a standalone waterproofer.
The technical insight
The defining technical trait is damp tolerance. A standard solvent or 100%-solids epoxy primer relies on a dry, vapour-stable substrate; applied to moist concrete it suffers amine blush, osmotic blistering or interfacial disbondment as trapped water migrates. Nitoprime 57’s water-based two-component epoxy chemistry is designed to wet out and key to a saturated-surface-dry (SSD) substrate, so the bond develops at the moisture-laden interface instead of fighting it. The trade-off is that water-based epoxies generally cure more slowly and are more temperature- and humidity-sensitive than solvent-borne equivalents, so curing and overcoat windows lengthen in cool, humid or poorly ventilated conditions. The practical engineering lesson is to treat Nitoprime 57 as a moisture-bridging primer: aim for SSD (damp but no standing water, no glistening film, no puddles), respect the manufacturer’s overcoat interval so the next layer is applied while the primer is still chemically active, and confirm the full build-up — primer plus coating or repair mortar — is compatible and rated for the actual chemical and water exposure.
Where it is used
- Priming damp or wet concrete floors and walls before applying Fosroc epoxy coatings, screeds or overlays
- Bonding agent between hardened (old) concrete and freshly placed concrete or mortar in repair and build-up work
- Base primer in corrosion-protection build-ups for structures exposed to dilute acids, salts and mineral oils
- Surface preparation inside water-retaining structures, basements and below-grade slabs that cannot be fully dried
- Priming substrates in sewage, effluent (STP/ETP) and industrial wash-down areas before chemically resistant systems
- Interface preparation for concrete repair where curing schedules or monsoon conditions leave the substrate moist
Key advantages
- Can be applied to wet or damp surfaces, eliminating long substrate drying delays on Indian sites
- Water-based and low-odour, suitable for enclosed tanks, basements and occupied buildings
- Water-thinnable, so tools and overspray clean up without solvents
- Dual function as both a damp-tolerant primer and a hardened-to-fresh concrete bonding agent
- Cured film resists diluted acids, salt solutions, mineral oils and aliphatic hydrocarbons
- Part of the wider Fosroc system, so it pairs predictably with compatible Nitoflor, Nitocote and Nitobond products
Limitations & considerations
- It is a thin-film primer and bonding agent, not a waterproofing membrane or a finished wearing surface
- Damp tolerance means saturated-surface-dry, not standing water — puddles and free water must be removed first
- Water-based epoxy cures more slowly and is more sensitive to low temperature and high humidity than solvent-based primers
- Performance depends on correct surface preparation: laitance, oil and loose material must be removed
- Overcoat timing matters — applying the next layer outside the recommended window can compromise adhesion
- Not a substitute for addressing the source of persistent water ingress through the structure
Selection & best practice
Prepare the concrete mechanically (grit-blasting, scabbling or grinding) to remove laitance, curing compounds, oil and loose material, then bring the surface to a saturated-surface-dry condition — visibly damp but with no standing water, puddles or glistening film. Mix the full base and hardener units together in the supplied ratio; do not split-batch by eye. Apply a thin, even, continuous film by brush, roller or squeegee, working it into the surface and avoiding ponding in low spots. Apply the subsequent coating, screed or fresh concrete within Fosroc’s stated overcoat window so the primer is still chemically active. In cool, humid or unventilated areas allow extra cure time and provide ventilation. Always confirm the complete build-up against the current product datasheet for the specific exposure, and obtain the country-specific TDS from Fosroc for exact mixing ratio, coverage, pot life and overcoat times before starting on site.
Specifications
| Product type | Two-component, water-based epoxy resin (per Fosroc) |
| Number of components | 2 (base + hardener), site-mixed |
| Primary function | Primer for coatings on damp/wet substrates |
| Secondary function | Adhesive between hardened and fresh concrete or mortar |
| Damp-surface application | Yes — can be applied on wet or damp surfaces (per Fosroc) |
| Chemical resistance (cured) | Diluted acids, salt solutions, mineral oils, acyclic (aliphatic) hydrocarbons |
| Coverage | Approx. 0.2–0.3 kg/m² (distributor-listed; confirm on country TDS) |
| Cleaning | Water-thinnable / water clean-up |
| Mixing ratio, pot life, overcoat time | As per Fosroc country-specific TDS (confirm before use) |
Industry use cases
Water & wastewater (STP/ETP)
Primes damp internal concrete of sewage and effluent tanks before chemically resistant coatings, where the substrate stays moist and acid/salt exposure is high.
Basements & below-grade
Bridges the bond line on permanently damp basement rafts and retaining walls so epoxy coatings and screeds adhere without drying delays.
Concrete repair & rehabilitation
Acts as the bonding agent between sound old concrete and fresh patch concrete or mortar when casting against moist, recently exposed surfaces.
Industrial flooring
Prepares green or moisture-affected floor slabs ahead of Fosroc epoxy floor systems where production schedules leave no time for full drying.
Coastal & marine-influenced structures
Provides a salt- and dilute-acid-resistant primer base on damp concrete in humid, chloride-laden coastal environments.
Frequently asked questions
What is Fosroc Nitoprime 57 used for?
Can Nitoprime 57 really be applied on wet concrete?
Is Nitoprime 57 a waterproofing product?
What is the coverage of Nitoprime 57?
What chemicals does the cured primer resist?
How is Nitoprime 57 different from solvent-based Fosroc primers?
How we position Fosroc Nitoprime 57
Within the Fosroc range, Nitoprime 57 is the damp-tolerant member of the Nitoprime primer family. Where Nitoprime 25/27/30 (solvent or solvent-free epoxy primers) and Nitozinc/Nitoprime Zincrich (corrosion primers for steel) demand dry substrates, Nitoprime 57 is specified precisely because the concrete is wet. As a bonding agent it overlaps with Nitobond EP (epoxy bonding agent) and Nitobond SBR (acrylic/SBR bonding aid); the distinction is its combined primer-plus-bond function on moist surfaces. Downstream it typically sits beneath Fosroc systems such as Nitoflor epoxy floor coatings/screeds and Nitocote chemical-resistant coatings. Against competitors, the closest equivalents in the Indian market are Sika’s damp-tolerant epoxy primers (e.g. Sikafloor/Sikadur damp-substrate primers), MBS (MYK/MBCC) Emaco and damp-tolerant epoxy primer lines, Dr. Fixit’s epoxy primer and bonding-agent range, and STP (Pidilite) Zentrifix/epoxy primers. For Space Arc Engineering’s customers, the honest positioning is: reach for Nitoprime 57 when the deciding factor is moisture on the substrate; if the surface is genuinely dry, a solvent-free epoxy primer may cure faster, and if the job is purely a hardened-to-fresh concrete bond on a sound dry interface, Nitobond EP is the more direct choice.
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