Fosroc Nitoproof RS
A single-component, water-based acrylic copolymer coating that waterproofs, reflects and decorates roofs in one system, reinforced with Fosroc Scrim 2250 for full crack-bridging protection.
What is it?
A single-component, solvent-free, water-based acrylic copolymer liquid coating that cures to a flexible, elastic, weather-resistant waterproofing and decorative membrane for roofs.
Where is it used?
Old and new roofs across concrete, asbestos-cement and corrugated sheeting, felt and timber substrates, plus gutters and ancillary roof areas (it is not applied over bare bituminous surfaces).
Why use it?
It combines waterproofing, UV-reflective decoration and crack-bridging in one easy brush, roller or spray application, with excellent opacity, good adhesion to concrete and metal, and high elongation for movement.
How is it applied?
Apply two coats over a clean, sound, primed substrate at roughly 5 m2 per litre per coat (200 microns WFT), allowing each coat to dry; embed Fosroc Scrim 2250 between coats at detailing and over cracks for a fully reinforced membrane.
About Fosroc Nitoproof RS
Fosroc Nitoproof RS (the product formerly marketed as Nitoproof RS200) is a liquid-applied roof waterproofing and protective decorative coating from Fosroc’s constructive-solutions range. It is a single-component, water-based acrylic copolymer that is supplied ready to use and cures by simple evaporation of water to form a continuous, seamless elastomeric film. Because the polymer backbone is naturally elastic, the cured coating stays flexible over a wide temperature range and resists ozonolysis and oxidative degradation, which are the slow ageing mechanisms that cause many roof coatings to chalk, embrittle and crack over time. For Indian conditions, where flat and low-slope roofs swing between intense summer heat and monsoon saturation, this combination of flexibility and weathering resistance is the main reason specifiers reach for an acrylic system of this type. Nitoproof RS is intended as a maintenance and refurbishment coating as much as a new-build product. It bonds well to aged concrete roof slabs, asbestos-cement and corrugated metal sheeting, bituminous felt that has already been laid, and timber, making it a practical overlay for tired roofs that are leaking but not structurally failed. Its high opacity and pigmented finish mean it also serves as a reflective, decorative topcoat, so a single material both stops water ingress and improves the roof’s appearance and solar reflectance. Where genuine crack-bridging and reinforcement are required, the coating is designed to be used together with Fosroc Scrim 2250, a polyester reinforcing fabric that is sandwiched between coats to create a tough, monolithic, fully reinforced membrane at gutters, upstands, junctions and over moving cracks. Space Arc Engineering, an authorised Fosroc distributor and applicator serving Delhi NCR and Pan-India, supplies Nitoproof RS alongside the primers and reinforcement needed for a complete, warranty-grade roof system.
The technical insight
The performance of Nitoproof RS comes from its acrylic copolymer chemistry rather than from a chemical cure. As a water-dispersed system it contains no isocyanates or solvents, so it is low-odour, non-flammable and safe to apply on occupied buildings, but it must be applied and allowed to dry above the minimum film-forming temperature and out of imminent rain, because the film forms only as water leaves the coating. The cured membrane is genuinely elastomeric: published data indicate elongation at break greater than 300 percent (typically around 400 percent) with tensile strength building from over 1.2 N/mm2 at 24 hours to over 2.0 N/mm2 at full cure around 7 days. That high extensibility is what allows the coating, especially when reinforced with Scrim 2250, to bridge fine shrinkage and thermal cracks without splitting. Coverage is governed by wet film thickness: at the recommended 200 microns WFT the practical rate is about 5 m2 per litre per coat, and Fosroc’s two-coat regime therefore lays down roughly 0.4 mm of dry film, with heavier builds (down to about 1 m2 per litre) used where a thicker, more robust membrane is wanted. Because the binder is acrylic, the system is best kept off bare bituminous substrates, where bleed and incompatibility can occur, and off areas of permanent water immersion such as tanks or ponds, for which Fosroc’s polyurethane and cementitious membranes are the correct choice.
Where it is used
- Waterproofing and refurbishment of old and new flat or low-slope roof slabs
- Overcoating aged or leaking bituminous felt roofs (over the felt, not bare bitumen)
- Protective decorative coating for asbestos-cement and corrugated metal roofing sheets
- Reflective, UV-stable finish coat to reduce roof surface temperatures
- Waterproofing of roof gutters, valleys, upstands and parapet junctions
- Crack-bridging treatment over hairline and thermal cracks when reinforced with Scrim 2250
- Maintenance recoating of previously coated acrylic roof membranes
- Protective coating on exposed concrete and metal roof elements requiring good opacity and adhesion
Key advantages
- Single-component and ready to use, so no on-site mixing of two parts and minimal wastage
- Water-based and solvent-free, giving low odour, low flammability and safer use on occupied buildings
- Excellent weather and UV resistance with high opacity for a durable decorative finish
- High elongation (typically around 400 percent) for genuine crack-bridging when reinforced
- Good adhesion to concrete, metal, asbestos-cement, felt and timber substrates
- Simple application by brush, roller or spray, suiting both detailing and large open roof areas
- Compatible with Fosroc Scrim 2250 for a fully reinforced, monolithic membrane at vulnerable details
- Economical whole-of-roof solution that combines waterproofing, decoration and reflectivity in one product
Limitations & considerations
- Not suitable for direct application over bare bituminous or coal-tar surfaces due to incompatibility and bleed risk
- Not designed for permanent water immersion such as water tanks, ponds or below-grade tanking
- As a water-based film former it cannot be applied in rain, fog or when rain is imminent before the film has dried
- Application and curing require ambient and surface temperatures above the minimum film-forming temperature; cold or very humid conditions slow drying
- Requires a clean, sound, properly prepared and usually primed substrate to achieve stated adhesion
- Crack-bridging over larger or live cracks needs reinforcement with Scrim 2250 rather than the coating alone
- Coverage and final film build depend heavily on substrate texture and applied wet film thickness, so site rates can differ from theoretical figures
- Pedestrian or trafficked areas need a separate wearing or protection layer, as the coating is a protective membrane, not a traffic-deck system
Selection & best practice
Always begin with substrate preparation: the roof must be clean, sound, dry and free of laitance, loose material, oil, fungal growth and ponded water, with cracks and defects made good and a suitable Fosroc primer applied where the substrate calls for it. Apply Nitoproof RS in two coats, allowing the first coat to dry fully before the second, and target the recommended 200 microns wet film thickness (about 5 m2 per litre per coat) using a brush, roller or spray to suit the area. At all vulnerable details, gutters, upstands, parapet junctions and over cracks, embed Fosroc Scrim 2250 into the wet first coat and overcoat it so the fabric is fully sandwiched and wetted out. Plan application around the weather: do not coat when rain is imminent or in fog, and avoid application below the minimum film-forming temperature. For an audited specification, correct primer selection and trained applicators across Delhi NCR and Pan-India, work with Space Arc Engineering as the authorised Fosroc partner.
Specifications
| Product type | Single-component, water-based acrylic copolymer roof waterproofing and decorative coating |
| Former name | Nitoproof RS200 |
| Curing mechanism | Air-drying by evaporation of water (no chemical cure, no solvents) |
| Coverage | Approx. 5 m2 per litre per coat at 200 microns WFT (heavier builds down to ~1 m2/litre) |
| Number of coats | 2 coats minimum |
| Wet film thickness | 0.4 – 1.0 mm WFT per coat (200 microns at recommended rate) |
| Elongation at break | >300% (typically ~400%) |
| Tensile strength | >1.2 N/mm2 at 24 hours; >2.0 N/mm2 at 7 days (full cure) |
| Reinforcement | Fosroc Scrim 2250 polyester fabric, sandwiched between coats at details and cracks |
| Suitable substrates | Concrete, asbestos-cement, corrugated metal sheet, existing felt, timber (excludes bare bitumen) |
| Application method | Brush, roller or spray |
| Colours | White / Stucco Grey (regional ranges also list Black, Neutral, Oxide Red, Grey) |
| Pack size | 20 litre pail |
Industry use cases
Residential and housing societies
Refurbishing leaking RCC terrace slabs and chajjas on apartments and independent houses, where a reflective white acrylic coat both stops monsoon ingress and lowers top-floor heat gain.
Industrial and warehouse roofing
Overcoating large spans of asbestos-cement and corrugated metal roofing sheets to seal fastener leaks and rust pinholes while adding a protective, decorative, UV-stable finish.
Commercial and institutional buildings
Maintenance recoating of office, school and hospital roofs and gutters, using a low-odour water-based product that can be applied while the building stays occupied.
Heritage and ageing-stock refurbishment
Overlaying tired bituminous-felt and timber roofs with a scrim-reinforced membrane to extend service life without full tear-off, a cost-sensitive route for older Indian building stock.
Infrastructure and utility structures
Protecting and waterproofing exposed concrete and metal roof elements on pump houses, substations and ancillary buildings where opacity, adhesion and weathering resistance matter.
Frequently asked questions
What exactly is Fosroc Nitoproof RS and what was it called before?
How many coats are needed and what coverage should I expect?
Can Nitoproof RS bridge cracks on its own?
Which surfaces is it suitable for, and which should be avoided?
Is it safe to apply on an occupied building in Indian conditions?
How does Nitoproof RS compare with other Fosroc roof membranes?
How we position Fosroc Nitoproof RS
Nitoproof RS sits at the economical, acrylic end of Fosroc’s waterproofing portfolio, purpose-built for roof refurbishment, reflectivity and decoration rather than heavy-duty or immersed duty. Within the Fosroc range it pairs naturally with Fosroc Scrim 2250 reinforcement and the appropriate Nitoproof primer, and it complements rather than competes with the polyurethane Nitoproof family (such as Nitoproof 600, 600PF and 800) used where a thicker, more elastomeric or trafficable membrane is specified, and with Brushbond cementitious coatings used for masonry and below-grade positive and negative side waterproofing. Against the wider Indian market, an acrylic roof coating of this class competes with Sika’s acrylic roof products (for example the Sikalastic and SikaGuard ranges), Pidilite Dr. Fixit’s Roofseal and Newcoat acrylic coatings, STP Limited’s acrylic roof coatings, and MBS-type acrylic systems; the practical differentiator for an Indian specifier is usually the combination of Fosroc’s documented data, scrim-reinforced detailing system, and the local specification and applicator support provided by an authorised partner such as Space Arc Engineering across Delhi NCR and Pan-India. Buyers should choose Nitoproof RS when the objective is a cost-effective, UV-reflective, crack-bridging refurbishment coat on an exposed roof, and step up to a polyurethane or cementitious Fosroc system when the application involves permanent immersion, foot traffic, or below-grade tanking.
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