Fosroc Nitoprime 115
A non-flammable, low-odour, water-based adhesion primer that lets water-based paints, coatings, membranes and adhesives grip smooth, dense, non-porous surfaces — a clean alternative to grinding and acid etching.
What is it?
A single-component, water-based adhesion primer engineered to bond onto smooth, dense and non-porous substrates such as metals, glazed tiles and dense concrete.
Where is it used?
Used as the tie-coat beneath Fosroc Nitoproof water-based waterproofing membranes and water-based paints/adhesives on non-absorbent surfaces in bathrooms, balconies, terraces and refurbishment work.
Why use it?
It replaces hazardous solvent primers and mechanical etching/grinding, is low-VOC (22 g/L), non-flammable, fast-drying and gives excellent water resistance — saving labour and dust on site.
How is it applied?
Lightly stir, then roller or brush a thin film onto clean, prepared substrate (vertical, horizontal or overhead); it is tack-free in ~15 minutes and dry-film in ~30 minutes at 23°C before overcoating with a water-based system.
About Fosroc Nitoprime 115
Fosroc Nitoprime 115 solves a recurring headache on Indian sites: getting water-based waterproofing membranes, paints and adhesives to stick to surfaces that simply will not absorb them. Smooth metals, glazed tiles, powder-coated sections, dense polished concrete and rigid plastics all reject conventional water-based coatings, and the traditional fixes — acid etching, sanding or grinding — are slow, dusty, hazardous and often impractical inside an occupied flat or above a finished ceiling. Nitoprime 115 is a water-based primer formulated specifically to create a chemical key on these non-porous substrates so that subsequent water-based systems develop a reliable bond.\n\nThe product is a green, water-soluble (in its wet state) primer with a mixed specific gravity of about 1.3 kg/litre and a VOC content of only 22 g/litre, which keeps it compliant with low-emission specifications and pleasant to use in enclosed wet areas. Because it is non-flammable and free of hazardous solvent odours, applicators can prime bathrooms, lift pits, basements and balconies without the ventilation and fire-safety constraints that solvent etch primers demand. It is applied by roller or brush as a thin, lightly stirred film and reaches tack-free condition in roughly 15 minutes and a dry film in about 30 minutes under normal 23°C conditions, allowing fast turnaround between trades.\n\nWithin the Fosroc system, Nitoprime 115 is the recommended adhesion primer ahead of Nitoproof water-based membranes on non-porous substrates, and it can also be rendered or tiled over (referencing the Nitoprime 120 render route) using a polymer-modified cementitious tile adhesive for direct fixing. For Space Arc Engineering clients across Delhi NCR and pan-India — applicators, waterproofing contractors and PMC teams — it is the clean, code-friendly answer to the ‘how do we bond over this glazed tile / metal deck / dense slab?’ question that comes up on almost every refurbishment and wet-area job. It is important to note that Fosroc lists more than one product under the Nitoprime 115 name across regions; this page describes the water-based non-porous primer documented in the dated TDS, not the two-pack epoxy bridge-deck primer of the same number in some legacy catalogues.
The technical insight
Adhesion onto non-porous substrates is fundamentally different from priming concrete or screed. On absorbent surfaces a primer keys mechanically by soaking into open pores; on glazed tile, stainless steel or dense slab there are effectively no pores, so the bond must come from the primer’s own surface chemistry. Nitoprime 115 is engineered as a water-based film with adhesion-enhancing polymers that wet out and grip these smooth surfaces, then leave a receptive dried film that a following water-based membrane, paint or adhesive can lock onto. This is why the TDS is emphatic that only water-based finishing systems may be applied over it — a solvent-based topcoat can re-soften or interfere with the thin primer film and break the bond chain. The dual drying behaviour (tack-free at ~15 min, full dry film at ~30 min at 23°C) reflects water evaporation rather than chemical cure, which is why Fosroc instructs at least doubling the drying time at 10°C and not applying membrane until the primer is completely dry — trapping moisture under a membrane is the classic cause of blistering. With a pH of around 8 and 100% water-solubility when wet, clean-up and overspray control are simple, but once cured the film must be removed with Fosroc Solvent 10 or mechanically, confirming it has crosslinked into a water-resistant layer.
Where it is used
- Adhesion primer over glazed/ceramic tiles to enable re-tiling or membrane application without etching or grinding
- Primer over dense, smooth concrete and polished slabs before water-based waterproofing membranes
- Primer over metals — galvanised iron, zincalume, stainless steel, copper, brass and most metals — and Scyon/CFC fibre-cement sheeting
- Tie-coat beneath Fosroc Nitoproof water-based membranes on non-porous wet-area substrates (bathrooms, balconies, terraces)
- Priming sound painted or powder-coated surfaces (with light 240-grit abrasion) prior to water-based recoating
- Priming PVC and other non-PE rigid plastics (with light abrasion) before water-based coatings or adhesives
Key advantages
- Low VOC content of just 22 g/litre — suitable for enclosed wet areas and low-emission specifications
- Non-flammable and free of hazardous solvent odours, unlike traditional etch/solvent primers
- Cost-effective, dust-free alternative to mechanical grinding or acid etching of non-porous surfaces
- Fast drying — tack-free in ~15 minutes and dry film in ~30 minutes at 23°C for quick trade turnaround
- Excellent water resistance once cured, with proven compatibility as the primer for Nitoproof water-based membranes
- Can be applied to vertical, horizontal and overhead surfaces by simple roller or brush
- Easy wet-state clean-up with water; can be rendered or tiled over with polymer-modified cementitious adhesive
Limitations & considerations
- Only water-based finishing systems may be applied over it — not suitable for solvent-based finishes
- Not designed as a stand-alone UV-exposed or trafficable sealer
- Not to be used as a stand-alone product in permanently immersed areas
- Must be completely dry before applying membrane; drying time must be at least doubled at 10°C to avoid trapped moisture and blistering
- Over powder-coated metals, PVC and rigid plastics, light 240-grit abrasion (and Fosroc Solvent 10 wipe for powder coat) is required first
- On CFC sheeting a water-droplet porosity test is advised — porous grades should instead be primed with Nitoprime 120
- Once cured it can only be removed by Fosroc Solvent 10 or mechanical means
Selection & best practice
Always start with a clean, sound, stable substrate — free of dust, loose material, degraded coatings, laitance, curing compounds, release agents and oil/grease. Wipe down with a damp cloth and let the surface dry to lift residual dust. Lightly abrade powder-coated metal, PVC and rigid plastics with 240-grit paper (wipe powder-coat with Fosroc Solvent 10) before priming, and run a water-droplet test on CFC to confirm it is genuinely non-porous. Stir Nitoprime 115 lightly and apply a thin, even film by roller or brush; do not over-build. Allow tack-free (~15 min) and full dry film (~30 min at 23°C) and double the wait at 10°C — never overcoat until completely dry. Overcoat only with water-based systems (e.g. Nitoproof membranes). Plan stock and lead times with Space Arc Engineering, your authorised Fosroc distributor in Delhi NCR and pan-India, to ensure fresh, in-date material and the correct companion membrane.
Specifications
| Product type | Water-based adhesion primer for non-porous substrates |
| Colour | Green |
| Specific gravity (mixed product) | 1.3 kg/litre |
| Viscosity | 8000 mPa.s |
| pH | 8 |
| VOC content | 22 g/litre |
| Water solubility (wet state) | 100% soluble |
| Flammability | Nil (non-flammable) |
| Tack-free time (23°C) | 15 minutes (varies with surface porosity) |
| Dry film time (23°C) | 30 minutes |
| Low-temperature application | Double drying time as a minimum at 10°C |
| Application method | Roller or brush; vertical, horizontal and overhead |
| Overcoating | Water-based systems only (e.g. Nitoproof membranes) |
| Clean-up | Water while wet; Fosroc Solvent 10 or mechanical once dry |
| Pack size (example) | 4 litre (product code FC000600-4L) |
Industry use cases
Residential wet-area waterproofing
Priming glazed tiles and dense bathroom/balcony slabs so Nitoproof water-based membranes bond without ripping out old tiling — ideal for occupied-flat refurbishments in Delhi NCR high-rises.
Commercial & institutional refurbishment
Re-tiling over existing glazed surfaces in hospitals, hotels and schools without dusty grinding, keeping spaces usable and reducing downtime.
Metal substrates & MEP
Bonding water-based coatings/membranes onto galvanised, zincalume, stainless, copper and brass surfaces — duct enclosures, metal decks and plant areas.
Podiums, terraces & balconies
Acting as the adhesion tie-coat over dense, power-trowelled concrete before water-based waterproofing on roofs, terraces and planter areas.
Frequently asked questions
Is Fosroc Nitoprime 115 water-based or epoxy?
What surfaces is it designed for?
How long before I can overcoat it?
Can I use a solvent-based paint or membrane over it?
Can it be tiled or rendered over?
Where can I buy Fosroc Nitoprime 115 in India?
How we position Fosroc Nitoprime 115
Nitoprime 115 is best understood as a specialist non-porous adhesion primer, not a general concrete primer. Within the Fosroc range it pairs with Nitoproof water-based membranes (its intended topcoat) and complements Nitoprime 120, which is the correct choice when a surface such as porous-grade CFC proves absorbent. Where a different substrate or chemistry is needed, Fosroc also offers Nitoprime Zincrich for steel corrosion protection and two-pack epoxy primers for solvent-based or structural build-ups. Against competitor systems, the equivalent ‘bonding/adhesion primer for difficult non-porous surfaces’ roles are filled by products like Sika’s bonding primers and Sikalastic primer range, Dr. Fixit’s Primeseal/bonding primers, STP (Shalimar/STP Limited) primer coats, and MBS/MYK Laticrete tile-bonding primers. Honestly, the right choice depends on the specified membrane manufacturer — the primer should match the membrane system. Nitoprime 115’s distinct edge is its low-VOC, non-flammable, water-based formula that genuinely avoids grinding and etching on glazed tile and metal. Space Arc Engineering can advise on the correct Fosroc primer-and-membrane pairing or a like-for-like alternative based on your project specification.
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