Fosroc Nitoprime 150
A single-component solvent-based re-activator that reopens the overcoating window on cured Fosroc polyurea and polyurethane membranes, restoring chemical intercoat adhesion without removing the existing coat.
What is it?
A clear, single-component, solvent-based surface treatment that chemically re-activates cured polyurea and polyurethane waterproofing films so a fresh coat can bond when the manufacturer’s maximum overcoating time has already been exceeded.
Where is it used?
On Fosroc polyurea and PU membrane systems – Nitoproof 800, Nitoproof UVR Topcoat and sprayed Fosroc Polyurea – on podiums, terraces, water-retaining structures, tunnels, car parks and industrial decks where a recoat was delayed.
Why use it?
Once a polyurea or PU film fully cures it loses surface reactivity, so a new coat physically peels off. Nitoprime 150 reopens that bond window in minutes, avoiding the cost and downtime of mechanically abrading or stripping an otherwise sound membrane.
How is it applied?
Wipe the cured surface with a clean lint-free cloth charged with the product at about 10 g/m2 (roughly 100 m2 per kg), overlapping 50-100 mm onto the previous coat, then apply the next coat once the surface is touch-dry, typically after 20-30 minutes at 20-35 C.
About Fosroc Nitoprime 150
Fosroc Nitoprime 150 is a specialist ancillary product within the Fosroc waterproofing range, and it solves a problem that is far more common on Indian sites than most specifiers admit: the recoat that did not happen on time. High-performance liquid membranes such as polyurea and aromatic polyurethane cure by reacting at the surface, and they will chemically knit to the next coat only within a defined overcoating window. Miss that window – because of an unexpected monsoon shower, a labour shortage, a delayed material delivery, or simply a curing day that ran longer than planned in Delhi NCR’s summer heat – and the freshly applied coat can no longer form a chemical bond with the cured film beneath it. The result is a mechanical, peelable interface that fails in service. Nitoprime 150 is the engineered answer to exactly this situation. It is a clear, low-viscosity, single-pack solvent-based treatment that softens and reactivates the cured polymer surface so that intercoat adhesion is restored, allowing work to continue without the expensive alternative of grinding, blasting or completely stripping a membrane that is otherwise perfectly sound. Because it is wiped on at a very thin film and flashes off in well under an hour, it adds minimal time to the programme. For a distributor like Space Arc Engineering serving applicators across Delhi NCR and pan-India, it is the kind of small-pack product that quietly rescues large waterproofing contracts – turning a potential tear-out into a 30-minute remedial step. It is important to understand what Nitoprime 150 is not: it is not a primer for fresh concrete or for first coats, it is not a corrosion primer, and it is not a stand-alone waterproofer. It is a system-specific re-activator that belongs to, and is only used with, Fosroc’s cured polyurea and polyurethane coatings.
The technical insight
The functional chemistry of Nitoprime 150 is surface re-activation rather than priming. Polyurea and polyurethane films build their final cohesive strength as residual isocyanate, urea and urethane groups at the surface complete their reaction; once that reaction is complete, the surface is essentially inert and a new coat has nothing to react with. Nitoprime 150 works by carrying active solvent into that cured film: the solvent briefly swells and softens the top few microns of the polymer, re-exposing reactive sites and creating a tacky, partially mobile zone into which the next coat can diffuse and form a continuous, monolithic bond instead of sitting as a discrete peelable layer. This is why dosage discipline matters – the published rate is roughly 10 g/m2 (around 100 m2 per kg), applied as a wiped film with a lint-free cloth, and puddling must be strictly avoided. Too little solvent and the surface is not adequately reactivated; too much, or pooled, and the solvent can over-soften and damage the membrane or leave a weak, slow-drying boundary layer. The treatment must flash off to touch-dry before overcoating – 20-30 minutes at 20-35 C, extending to roughly 45-90 minutes at 10-20 C – and the overlap onto the previous coat is kept at 50-100 mm so the reactivated zone always exceeds the new coat’s edge. Because the active ingredient is a flammable organic solvent (density around 1 kg/litre), the product is governed by its solvent behaviour, not by film-forming resin chemistry.
Where it is used
- Re-establishing intercoat adhesion on cured Fosroc Nitoproof 800 polyurethane waterproofing where the overcoating time was exceeded
- Re-activating Nitoproof UVR Topcoat before applying an additional top coat or repair patch
- Reopening the bond window on sprayed Fosroc Polyurea membranes on podium decks, terraces and basements
- Remedial recoating of polyurea/PU membranes in water-retaining structures such as STPs, ETPs and water tanks (with potable approval checked separately)
- Localised repair and feathering-in of damaged areas on existing cured polyurea/PU systems
- Resuming a multi-coat membrane build-up after an unplanned weather or schedule delay on car park decks and industrial floors
- Tunnel, metro and infrastructure waterproofing where access constraints force long gaps between membrane coats
Key advantages
- Restores chemical intercoat adhesion on fully cured polyurea/PU films, avoiding peel failure at the coat interface
- Saves a sound membrane from being mechanically abraded, blasted or completely stripped and re-laid
- Very fast working step – touch-dry and ready to overcoat in as little as 20-30 minutes in warm Indian conditions
- Extremely economical in use, covering around 100 m2 per kilogram at the recommended wipe rate
- Simple cloth-wipe application needs no special spray or mixing equipment and suits remedial and patch work
- Clear, single-component product with no mix ratio, batching error or pot-life to manage on site
- Backed by Fosroc’s documented system compatibility with Nitoproof 800, Nitoproof UVR and Fosroc Polyurea
Limitations & considerations
- Strictly a system-specific re-activator for cured polyurea/PU coatings – not a primer for concrete, metal or fresh first coats
- Flammable solvent-based product; cannot be used near naked flames, sparks or ignition sources and needs good ventilation
- Effectiveness depends on correct dosage – puddling or over-application can over-soften or damage the membrane
- Not a waterproofer or repair compound in itself; it only conditions the surface for the next coat
- Working window is temperature-sensitive – drying slows markedly below 20 C and application is limited to 5-35 C
- Cannot be applied above 85% relative humidity, which constrains monsoon-season and high-humidity coastal work
- Small 1 kg pack and 12-month shelf life mean it is bought for specific remedial jobs, not stockpiled
- Verify potable-water and food-contact suitability separately for the overall system before tank applications
Selection & best practice
Treat Nitoprime 150 as a precision remedial step, not a routine coat. First confirm the existing membrane is sound, fully cured, clean and dry – the re-activator restores adhesion but will not rescue a contaminated, damp or delaminating surface, so wash off dust, grease and laitance and let it dry before starting. Decant only what you can use, keep the container closed, and apply with a clean lint-free cloth at about 10 g/m2 in a thin, even wipe; never pour or flood, and never leave puddles, as pooled solvent can soften and weaken the membrane. Overlap 50-100 mm onto the previous coat so the reactivated zone always sits beyond the new coat’s edge. Let the surface flash to touch-dry before overcoating – allow 20-30 minutes at 20-35 C and 45-90 minutes at 10-20 C – and apply the next coat the same working day rather than leaving the reactivated surface exposed overnight to dust and dew. Work only within 5-35 C and below 85% RH; in Delhi NCR’s summer, schedule wiping for early morning or late afternoon to keep the solvent from flashing off too fast. Because it is flammable, eliminate ignition sources, ensure cross-ventilation in enclosed decks, basements and tanks, and use solvent-rated gloves and respiratory protection per the SDS. Always cross-check the current Fosroc TDS and SDS for the specific membrane being recoated, and contact Space Arc Engineering’s technical desk when in doubt about overcoating intervals.
Specifications
| Product type | Single-component, solvent-based surface re-activator (primer-type ancillary) |
| Primary function | Re-activates cured polyurea/PU surfaces to restore intercoat adhesion after the overcoating window has lapsed |
| Compatible systems | Fosroc Nitoproof 800, Nitoproof UVR Topcoat, Fosroc Polyurea |
| Appearance / colour | Clear liquid |
| Density | Approx. 1 kg/litre |
| Coverage | Approx. 100 m2 per kg (applied at ~10 g/m2) |
| Application method | Wipe with clean lint-free cloth; avoid puddling |
| Overlap onto previous coat | Minimum 50 mm, preferably 100 mm |
| Application temperature | 5 C to 35 C (substrate and ambient) |
| Maximum relative humidity | 85% |
| Dry-to-overcoat time | 20-30 min at +20 C to +35 C; 45-90 min at +10 C to +20 C |
| Flammability | Flammable – keep away from naked flames and ignition sources |
| Pack size | 1 kg |
| Shelf life | 12 months from date of manufacture (unopened, correct storage) |
Industry use cases
Commercial podiums & terraces
On a Gurugram commercial podium coated with Fosroc Polyurea, a monsoon delay pushed the recoat past the overcoating window; Nitoprime 150 reactivated the cured film so the second coat bonded without stripping the membrane.
Water & wastewater (STP/ETP)
For polyurea-lined effluent tanks in industrial estates, the re-activator lets applicators resume a stalled multi-coat build-up, restoring a monolithic lining where access scheduling forced long gaps between coats.
Car parks & industrial decks
Phased recoating of Nitoproof 800 decks in multi-level car parks often runs over the bond window between bays; a quick cloth-wipe of Nitoprime 150 keeps the deck system continuous across construction joints.
Metro, tunnel & infrastructure
In tunnels and basements where ventilation and access slow the work, the re-activator reopens the adhesion window on cured PU/polyurea so coats applied days apart still knit into one membrane.
Remedial & patch repair
Maintenance teams use it to feather new material into localised damaged or worn areas of an existing cured polyurea membrane, avoiding a full re-lay of an otherwise sound roof or deck.
Frequently asked questions
What exactly does Fosroc Nitoprime 150 do?
Is Nitoprime 150 a primer for new concrete or metal?
How much do I need and how is it applied?
How long before I can apply the next coat?
Can it be used during the monsoon or in high humidity?
How does it compare with Sika, Dr. Fixit or STP equivalents?
How we position Fosroc Nitoprime 150
Fosroc Nitoprime 150 occupies a deliberately narrow niche: it is the rescue product for cured Fosroc polyurea and polyurethane waterproofing whose overcoating window has lapsed. It is best understood alongside the membranes it serves – Nitoproof 800, Nitoproof UVR Topcoat and Fosroc Polyurea – rather than against general primers. Within Fosroc’s own range, do not confuse it with the other Nitoprime grades (such as Nitoprime Zincrich for steel corrosion protection or concrete/substrate primers), which solve entirely different problems. Because it is membrane-specific, there is no true like-for-like competitor product; instead, rival systems from Sika, MBCC/Master Builders Solutions (formerly BASF), Pidilite Dr. Fixit and STP Limited each carry their own polyurea/PU coatings with their own intercoat-adhesion and reactivation procedures. The honest recommendation is to match the reactivator to the membrane: use Nitoprime 150 only on Fosroc polyurea/PU, and use a competitor’s equivalent step on a competitor’s membrane, never cross-mixing brands at the bond line. Space Arc Engineering, as an authorised Fosroc distributor in Delhi NCR and pan-India, supplies Nitoprime 150 together with the full Nitoproof and Polyurea system and provides applicator guidance on overcoating intervals so remedial recoats stay within warranty.
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