Fosroc Nitocote EPU
Flexible, UV-resistant hybrid epoxy-polyurethane coating that waterproofs and chemically protects concrete and steel in aggressive underground, sewage and marine environments.
What is it?
A two-component, solvent-borne hybrid epoxy-polyurethane protective coating supplied in pre-measured packs that cures to a flexible, impermeable film with combined chemical, abrasion and UV resistance.
Where is it used?
Concrete and steel in corrosive service: wall/floor protective linings, manholes and pipes, secondary containment bunds, sewage and effluent treatment works, seawater tanks and intakes, reservoirs, water-treatment plants and foundation waterproofing.
Why use it?
It pairs the chemical and adhesion strength of epoxy with the flexibility and UV stability of polyurethane in one primerless system, so a single coating resists acids, salts, sewage, seawater and sunlight while bridging minor movement that rigid epoxies cannot.
How is it applied?
Two coats of 200 microns each (400 micron total DFT) applied by brush, lamb’s-wool roller or airless spray onto a clean, sound, dry substrate; the second coat follows the first within 8 to 48 hours at 25 degrees C.
About Fosroc Nitocote EPU
Fosroc Nitocote EPU is a high-performance protective coating built on hybrid epoxy-polyurethane resin chemistry. It is supplied as a two-component system (base and hardener) in pre-measured quantities, so the only site step is thorough mixing before application. Once the components react, the material cures to a tough yet flexible film that behaves very differently from a conventional rigid epoxy: it carries the chemical resistance and concrete-bonding strength typical of epoxy, but adds the elongation, surface toughness and ultraviolet stability associated with polyurethanes. The result is a single coating that protects concrete and steel against the corrosive cocktail of conditions found in water, wastewater and industrial assets. For Indian contractors and consultants, Nitocote EPU sits in the protective-coatings/corrosion-control part of the Fosroc range and is specified where a structure faces both aggressive chemistry and the practical need for a coating that can flex slightly and withstand exposure without rapid chalking or embrittlement. It is explicitly free of coal tar, pitch and aromatic hydrocarbons, which makes it a cleaner replacement for older coal-tar epoxy linings still found on legacy water and sewage assets. Space Arc Engineering, as an authorised Fosroc distributor and applicator covering Delhi NCR and pan-India, positions Nitocote EPU as a go-to lining where a project needs waterproofing, chemical resistance and a degree of crack-accommodation in one product rather than a stack of separate systems.
The technical insight
The defining feature of Nitocote EPU is its hybrid backbone. A pure epoxy coating bonds superbly and resists chemicals but is rigid and chalks under UV; a pure polyurethane flexes and holds colour but is more sensitive during application. By hybridising the two, Fosroc delivers roughly 25 percent elongation at break (ASTM D412) and a tensile strength of about 10 N/mm2, so the film can bridge fine static cracks, especially when reinforced with an open-weave glass cloth of 100 to 300 g/m2 laid into the wet first coat. Adhesion to properly prepared concrete is reported as greater than the cohesive strength of the concrete itself (ASTM D4541), meaning failure occurs in the substrate, not the coating interface. Water absorption is very low at 0.2 percent (ASTM C413), underpinning its use as an impermeable waterproof barrier, and abrasion loss is only 0.1 g per 1000 cycles on a CS17 wheel (ASTM D4060). Chemical-resistance testing per ASTM D1308 (7-day immersion at 25 degrees C) confirms resistance to 10 percent hydrochloric acid, 25 percent sulphuric acid, 10 percent nitric acid and 15 percent phosphoric acid, plus tap water, seawater, groundwater and sewage. Specific gravity is about 1.48 at 25 degrees C. The practical engineering consequence is that one 400-micron two-coat system replaces what would otherwise need separate waterproofing and chemical-barrier products.
Where it is used
- Internal protective lining of sewage and effluent treatment tanks, channels and structures
- Manhole, wet-well and concrete pipe linings exposed to septic and sulphate attack
- Secondary containment bunds and dyke walls in chemical and industrial plants
- Seawater tanks, channels, intakes and marine concrete subject to chloride and salt attack
- Reservoirs, clear-water tanks and water-treatment plant structures (potable use subject to local approval)
- Wall and floor protective coating for concrete in corrosive process areas
- Foundation and below-ground waterproofing of concrete subject to groundwater
- Over-coating and refurbishment of previously coated, abraded concrete or grit-blasted steel surfaces
Key advantages
- Primerless on sound, dry, good-quality non-porous concrete, cutting one full coat and labour pass from the system cost
- Hybrid chemistry combines epoxy chemical/adhesion performance with polyurethane flexibility (~25% elongation) and UV resistance in a single product
- Free of coal tar, pitch and aromatic hydrocarbons, a cleaner alternative to legacy coal-tar epoxy linings
- Acts as an impermeable waterproof barrier with very low 0.2% water absorption
- Broad chemical resistance to dilute acids, alkalis, salt solutions, oils, fuels, seawater and sewage
- Does not support bacterial growth, valuable in sewage and water-treatment service
- Versatile application by brush, roller or airless spray, with higher builds achievable by spray
- Can be reinforced with glass-fibre cloth to increase thickness and bridge static cracks
- Adhesion reported greater than concrete tensile strength, so the bond is rarely the weak link
- 12-month shelf life in unopened packs for predictable procurement and stockholding
Limitations & considerations
- Must not be thinned with any solvent during mixing or application; Fosroc Solvent 102 is for tool cleaning only
- Pot life is short and temperature-dependent (3 hours at 25 degrees C, only 1.5 hours at 35 degrees C), demanding adequate labour to place mixed material
- Not to be applied below 5 degrees C, at 5 degrees C and falling, or when relative humidity exceeds 90%
- Must be protected from contact with water for the first 24 hours after application or discoloration can occur
- Slight UV discoloration may occur on exposure (cosmetic only, no loss of performance), and the cured film is not colour-stable in direct sunlight or against some chemicals
- Concrete must be cured at least 28 days or have moisture content below 5%; porous concrete or w/c ratio above 0.5 needs Nitoprime 31
- Steel substrates require grit blasting to Sa 2½ and immediate priming with Nitoprime 28 before coating
- Standard supply colour is grey only; other colours require minimum order quantities
- Hot-weather working practices are mandatory above 35 degrees C to manage the reduced pot life
Selection & best practice
Treat substrate preparation as the make-or-break step. For concrete, confirm at least 28 days cure or moisture content below 5%, remove all laitance, curing compound and release oils by grit blasting or diamond grinding, and fill blowholes and imperfections with Nitomortar TC2000 before coating. Prime only where needed: porous concrete or w/c ratio above 0.5 takes Nitoprime 31, while grit-blasted steel (Sa 2½) must be primed immediately with Nitoprime 28 and over-coated within 24 hours before rust forms. Mix the full hardener into the full base with a Jiffy mixer on a slow drill for 3 to 5 minutes until uniform, scraping sides and bottom, and apply at once. Lay each coat at a true 200 microns (5.0 m2/litre per coat) and apply the second coat within the 8 to 48-hour window at 25 degrees C. In Indian summer site conditions, schedule application for early morning or evening, store unmixed material in the shade, and mobilise enough crew to place each batch inside the 1.5-hour pot life at 35 degrees C. Keep fresh coating away from water for the first 24 hours.
Specifications
| Chemical type / system | Two-component hybrid epoxy-polyurethane coating |
| Standard colour | Grey (other colours subject to minimum order quantity) |
| Number of coats | 2 coats |
| Wet/dry film thickness | 200 microns per coat; 400 microns total DFT |
| Coverage (theoretical) | 5.0 m2/litre per coat at 200 microns |
| Specific gravity | ~1.48 at 25 degrees C |
| Pot life | 3 hours at 25 degrees C / 1.5 hours at 35 degrees C |
| Tack-free time | 6 hours at 25 degrees C / 3 hours at 35 degrees C |
| Full cure | 7 days at 25 degrees C / 4 days at 35 degrees C |
| Overcoat interval | 8 to 48 hours at 25 degrees C |
| Adhesion strength (ASTM D4541-95) | Greater than concrete (substrate failure) |
| Water absorption (ASTM C413) | 0.2% |
| Tensile strength (ASTM D412) | 10 N/mm2 |
| Elongation at break (ASTM D412) | Approx. 25% |
| Abrasion resistance (ASTM D4060) | 0.1 g / 1000 cycles (CS17 wheel) |
| Chemical resistance (ASTM D1308, 7-day soak) | Resistant to HCl 10%, H2SO4 25%, HNO3 10%, H3PO4 15%, tap/sea/ground water, sewage |
| Pack sizes | 10 and 20 litre packs |
| Shelf life | 12 months, unopened, stored 5 to 30 degrees C |
| Application methods | Brush, lamb’s-wool roller or airless spray |
| Application temperature limits | Not below 5 degrees C or RH above 90% |
Industry use cases
Water & Wastewater
Lining of sewage treatment tanks, manholes, wet wells and effluent channels where the coating must resist septic conditions, dilute acids and sulphate attack while not supporting bacterial growth.
Marine & Coastal
Protection of seawater tanks, intakes and channels and other coastal concrete against chloride-laden water and salt-solution attack, helped by the coating’s low water absorption and flexibility.
Industrial & Chemical Plants
Coating of secondary containment bunds, process-area floors and walls exposed to dilute acid, alkali and oil/fuel spillage, where one chemical-resistant barrier is preferred over multiple systems.
Infrastructure & Buildings
Foundation and below-ground waterproofing plus protective lining of reservoirs and water-treatment structures, combining an impermeable barrier with crack-bridging when reinforced with glass cloth.
Refurbishment
Over-coating of damaged or aged coal-tar epoxy linings on legacy water and sewage assets with a cleaner, coal-tar-free hybrid system after abrasion and surface preparation.
Frequently asked questions
Is Fosroc Nitocote EPU an epoxy or a polyurethane coating?
What total thickness and coverage should I specify?
Does Nitocote EPU need a primer?
What chemicals and environments can it resist?
Can it be used on water-retaining or potable-water structures?
What are the key application precautions in Indian site conditions?
How we position Fosroc Nitocote EPU
Within the Fosroc range, Nitocote EPU is the flexible, UV-resistant, coal-tar-free option in the protective-coatings family. It sits alongside Nitocote EPS (an epoxy coating in the same series) and the Nitoflor EPU flooring line, and is supported by Fosroc ancillaries used in the same system: Nitoprime 31 and Nitoprime 28 as situational primers, Nitomortar TC2000 to fill blowholes, and Fosroc Solvent 102 for tool cleaning. Where a project needs a rigid high-build chemical-resistant lining rather than flexibility, a straight epoxy such as Nitocote EPS or a Nitoflor epoxy screed may be more appropriate; where heavy negative-side or tanking waterproofing is the priority, Fosroc’s membrane systems come into play. Against competitor products, Nitocote EPU competes with Sika’s epoxy and PU protective coatings (for example the Sikagard and Sikafloor chemical-resistant ranges), MBS (MYK Schomburg) protective and tanking coatings, Dr. Fixit’s industrial waterproofing and protective-coating line, and STP’s epoxy/PU corrosion-protection systems. Its differentiator is the hybrid epoxy-PU balance of chemical resistance plus flexibility and UV stability in one primerless coat, which makes it a strong fit for sewage, marine and containment assets in Indian conditions. Space Arc Engineering can advise on the right Fosroc system, primer selection and reinforcement detailing, and supply Nitocote EPU and its ancillaries across Delhi NCR and pan-India.
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