Fosroc Nitoflor EPU
Flexible, tar-free epoxy-polyurethane protective coating for concrete floors, walls and sub-structures — chemical-resistant, waterproof and primerless on sound concrete.
What is it?
A two-pack, flexible protective floor and wall coating based on a hybrid combination of epoxy and polyurethane resins. The grade most commonly specified in this family is Nitoflor EPU100, applied as a two-coat system.
Where is it used?
Warehouses, factory and workshop floors and walls, car parks and traffic decks, clean rooms, and the waterproofing protection of foundations, sub-structures and buried concrete.
Why use it?
It combines the chemical and abrasion resistance of epoxy with the flexibility and crack-accommodation of polyurethane, while being totally free of coal tar, pitch and aromatic hydrocarbons — and it cures primerless on properly prepared concrete.
How is it applied?
Mix both packs mechanically for 3-5 minutes, then apply two coats by brush, roller or spray, each at a minimum 200 micron wet film thickness, with the second coat following 2-4 hours after the first at 35 degree C.
About Fosroc Nitoflor EPU
Fosroc Nitoflor EPU is a flexible, protective floor and wall coating built on a hybrid of epoxy and polyurethane resins. It is supplied as a two-pack (resin and hardener) system in pre-weighed quantities, ready for on-site mixing, and is positioned as a corrosion-resistant, tar-free coating for concrete and steel. Within the range, Nitoflor EPU100 (formerly Nitoflor EU100) is the standard grey-coloured grade for which Fosroc publishes a full technical data sheet; other shades are available subject to minimum order quantities, and conductive/dissipative and higher-build EPU2000/EPU3000 variants exist for static-control and screed applications.\n\nThe product’s defining idea is balance. Pure epoxy floor coatings give excellent chemical and abrasion resistance but are relatively rigid and can craze over hairline movement; pure polyurethanes are flexible and UV-stable but softer. Nitoflor EPU’s epoxy-polyurethane hybrid is engineered to deliver meaningful chemical and abrasion resistance together with genuine flexibility — the cured film records roughly 25% elongation at break and 10 N/mm-square tensile strength — so it tolerates minor substrate movement without losing its barrier. Equally important for Indian project specifications, it is environment-friendly: totally free of coal tar, pitch and aromatic hydrocarbons, which makes it suitable where carcinogenic coal-tar epoxies are no longer acceptable.\n\nFunctionally, Nitoflor EPU does three jobs at once. It is a chemical and abrasion-resistant wearing/protective coat for industrial floors and walls; it is an impermeable, waterproof barrier with very low water absorption (about 0.2%); and it offers excellent resistance to aggressive underground environments — alkalis, salt solutions, acidic ground water and sewage — making it a practical choice for foundations, pile caps, retaining walls and other buried concrete. On properly prepared, laitance-free concrete it is primerless, which removes a labour step and cost from the application sequence. On steel it is used after grit blasting (Sa 2.5), with Nitoprime 25 only where the prepared surface cannot be coated immediately.\n\nFor a contractor or consultant in India, the headline practical numbers are straightforward: a theoretical coverage of 5.0 m-square per litre per coat at 200 micron WFT, a workable pot life of 3 hours at 23 degree C (1.5 hours at 35 degree C), and a two-coat protective film typically around 0.3-0.4 mm built dry. It is supplied in 10 litre packs with a 12-month shelf life below 35 degree C.
The technical insight
The single most useful thing to understand about Nitoflor EPU is that it is a coating, not a screed — its job is a thin (roughly 200 micron-per-coat wet, two coats) chemically resistant, flexible, waterproof skin over sound concrete or blasted steel, not a thick self-levelling wearing floor. That distinction governs where it succeeds. The hybrid epoxy-polyurethane chemistry is what lets a thin film survive on a moving or buried substrate: with about 25% elongation at break (BS 2782) and 10 N/mm-square tensile strength, the film bridges shrinkage and thermal micro-movement that would craze a rigid pure-epoxy coat, while still resisting 10% HCl, 25% sulphuric acid, 10% nitric and 15% phosphoric acid plus sea water, ground water and sewage (ASTM D1308, 7-day immersion at 23 degree C). The two practical levers an applicator controls are temperature and film continuity. Pot life and recoat windows compress sharply with heat — pot life roughly halves from 3 hours at 23 degree C to 1.5 hours at 35 degree C, and tack-free time drops from 6 hours to 3 hours — so in Delhi NCR summer conditions the material must be kept cool, applied early or late in the day, and recoated within the 2-4 hour window (at 35 degree C) to guarantee intercoat adhesion. Because waterproofing and chemical resistance depend on an unbroken film, the 200 micron-per-coat minimum WFT and the two-coat minimum are not nominal — thin spots and pinholes are where corrosion and water ingress start. Where slip resistance is needed, the same coating doubles as an anti-slip system by blinding the base coat with Nitoflor Antislip Grain and sealing with a top coat at 5.0 m-square/litre, building a 0.75-2.0 mm textured finish.
Where it is used
- Protective and chemical-resistant coating for warehouse, factory and workshop concrete floors
- Wall coating for concrete protection in industrial and process buildings
- Car park decks and traffic deck protection systems
- Waterproofing and chemical protection of foundations, pile caps, sub-structures and buried concrete
- Lining and protection of concrete exposed to alkalis, salt solutions, acidic ground water and sewage
- Clean-room floors and walls requiring a non-absorbent, impermeable, bacteria-resistant surface
- Anti-slip floor finishes when combined with Nitoflor Antislip Grain (medium or fine texture)
- Over-coating and refurbishment of previously coated, abraded sound concrete or steel
Key advantages
- Flexible epoxy-polyurethane film (approx. 25% elongation at break) that tolerates minor substrate movement better than rigid epoxy coatings
- Environment-friendly and tar-free — totally free of coal tar, pitch and aromatic (carcinogenic) hydrocarbons
- Primerless on properly prepared concrete, saving a coat, labour and programme time
- Impermeable and waterproof with very low water absorption (~0.2%), giving a genuine barrier coat
- Excellent resistance to underground/buried conditions — alkalis, salt and acidic solutions, ground water and sewage
- Broad chemical resistance to dilute acids (HCl, sulphuric, nitric, phosphoric) verified by 7-day immersion testing
- UV resistance and resistance to bacterial growth, suiting clean rooms and exposed surfaces
- Versatile application by brush, roller or spray, and convertible to an anti-slip system
- Two-pack, pre-weighed packs reduce on-site dosing error; 12-month shelf life
Limitations & considerations
- It is a thin protective coating, not a high-build wearing screed — not a substitute for trowel-applied epoxy/PU screeds where heavy mechanical wear or thickness is required
- Performance depends entirely on substrate preparation: concrete must be laitance-free (grit blasted) and steel blasted to Sa 2.5 or equivalent
- Must be protected from contact with water for the first 24 hours after application, otherwise discolouration can occur
- Pot life and recoat windows shorten significantly in heat (pot life ~1.5 hours at 35 degree C), demanding disciplined hot-weather practice in Indian summers
- Not intended for application below 5 degree C; accelerated heating to force cure is not permitted
- Aromatic epoxy-PU chemistry can chalk/discolour under prolonged sunlight — an aliphatic topcoat such as Nitocote PU is preferable where long-term colour stability outdoors is critical
- Standard colour is grey; other shades require minimum order quantities
- Cured film thickness per coat is modest, so continuity and freedom from pinholes are essential for the waterproofing claim to hold
Selection & best practice
Begin with the substrate: remove all laitance and contamination by grit blasting (or equivalent mechanical preparation) so concrete is clean, sound and dust-free, and fill surface irregularities with Nitomortar FC or FCB before coating; on steel, blast to Sa 2.5 and coat immediately, using Nitoprime 25 only if there will be a delay. Skip priming on correctly prepared concrete. Mix the full resin and hardener packs together with a slow-speed drill and Fosroc Mixing Paddle MR3 for 3-5 minutes to a uniform consistency, and apply only as much as can be used within the pot life. Lay the first coat to a minimum 200 micron WFT, allow at least 2 hours at 35 degree C, then apply the second coat within the 2-4 hour window (at 35 degree C) again at minimum 200 micron WFT — do not exceed the over-coating interval or the bond suffers. In Delhi NCR summer conditions, store unmixed material in the shade or temperature-controlled store, keep tools and surfaces cool, avoid mid-day and direct-sun application, and crew the job so placement finishes within pot life. Keep the fresh film off water for 24 hours, clean tools with Fosroc Solvent 102 immediately, and for anti-slip finishes blind the base coat with Nitoflor Antislip Grain then seal with a top coat. Always confirm the chemistry against the actual exposure with the local Fosroc/Space Arc technical team before specifying.
Specifications
| Chemical type / system | Hybrid epoxy-polyurethane resin, two-pack (resin + hardener) |
| Standard colour | Grey (other colours subject to MOQ) |
| Number of coats | Two-coat application (minimum) |
| Wet film thickness | Minimum 200 microns per coat |
| Theoretical coverage | 5.0 m2/litre per coat @ 200 microns WFT |
| Specific gravity (ASTM D1475) | 1.48 g/cm3 at 23 degree C |
| Pot life (ASTM D2471) | 3 hours @ 23 degree C; 1.5 hours @ 35 degree C |
| Tack-free time (ASTM D1640) | 6 h @ 23 degree C; 3 h @ 35 degree C; 1-2 h @ 45 degree C |
| Min. over-coating time (ASTM D1640) | 8 h @ 23 degree C; 4 h @ 35 degree C; 2 h @ 45 degree C |
| Full cure (ASTM D1640) | 7 days @ 23 degree C; 4 days @ 35 degree C |
| Adhesion strength (ASTM D4541) | 1.5 – 2.5 N/mm2 (depending on substrate) |
| Tensile strength (BS 2782) | 10 N/mm2 |
| Elongation at break (BS 2782) | Approx. 25% |
| Water absorption (ASTM C570) | 0.2% |
| Chemical resistance (ASTM D1308, 7-day) | Resistant to 10% HCl, 25% H2SO4, 10% HNO3, 15% H3PO4, sea/ground water, sewage |
| Substrates | Properly prepared concrete (primerless) and grit-blasted steel (Sa 2.5) |
| Pack size | 10 litre packs (Nitoprime 25: 1 & 4 litre; Fosroc Solvent 102: 4 litre) |
| Shelf life / storage | 12 months below 35 degree C in warehouse conditions |
| Application temperature | 5 degree C to 45 degree C (hot-weather precautions above 35 degree C) |
| Note | Detailed values are per the Nitoflor EPU100 (formerly EU100) data sheet |
Industry use cases
Warehousing & logistics
A chemical- and abrasion-resistant, low-absorption coating for warehouse and distribution-centre floors and walls, easy to clean and resistant to bacterial growth.
Manufacturing & process plants
Protective floor and wall coating for factory floors, workshops and process areas exposed to dilute acid and salt spillage, where flexibility helps survive thermal and shrinkage movement.
Infrastructure & sub-structures
Waterproof, chemically resistant protection for foundations, pile caps, retaining walls and buried concrete exposed to aggressive ground water, sewage and salts.
Car parks & traffic decks
Flexible deck-protection coating that bridges minor movement and shields the structural concrete from water and de-icing/road salts.
Clean rooms & controlled environments
Non-absorbent, impermeable, bacteria-resistant floor and wall finish suited to clean rooms and hygiene-sensitive areas; conductive/dissipative EPU variants exist where static control is needed.
Refurbishment & maintenance
Over-coating of damaged or worn previously coated concrete/steel after abrasion, extending service life without full removal.
Frequently asked questions
Is Fosroc Nitoflor EPU an epoxy or a polyurethane coating?
What coverage and film thickness should I plan for?
Does Nitoflor EPU need a primer?
Is it suitable for underground and buried concrete?
How does heat affect application in Indian summer conditions?
How does it compare with a thick epoxy or PU floor screed?
Can it be made slip-resistant?
How we position Fosroc Nitoflor EPU
Within the Fosroc range, Nitoflor EPU sits as the flexible, tar-free protective coating that bridges pure-epoxy and pure-polyurethane behaviour — more movement-tolerant than rigid epoxy floor coatings such as Nitoflor SL/TF screed systems, and chemistry-matched to underground exposure. It is complemented by Nitoprime 25 (priming of steel), Nitomortar FC/FCB (filling substrate irregularities), Nitoflor Antislip Grain (slip-resistant finishes) and Fosroc Solvent 102 (cleaning); for UV-critical colour-stable topcoats, an aliphatic Nitocote PU finish is the logical partner, and Nitocote EPU serves the equivalent protective-coating role on walls and structures. The EPU family also extends to conductive/dissipative grades for static control and to higher-build EPU2000/EPU3000 variants. Against competitors, credible alternatives an Indian specifier may evaluate include Sika (Sikafloor epoxy-PU coatings and Sikagard protective systems), MBCC/Master Builders Solutions (MasterTop and MasterSeal coatings), Dr. Fixit/Pidilite (Roffe and Newcoat protective and waterproofing coatings) and STP Limited (epoxy and PU floor coatings). Where the brief is specifically a flexible, tar-free, primerless coating with strong resistance to buried and chemically aggressive conditions, Nitoflor EPU is a well-suited specification; where the priority is a thick mechanical wearing floor, long-term external colour stability, or a specialised static-dissipative finish, the screed grades, an aliphatic topcoat, or the conductive EPU variant respectively are the better fit. As an authorised Fosroc distributor and applicator serving Delhi NCR and Pan-India, Space Arc Engineering can supply Nitoflor EPU, confirm the correct grade against your exposure, and provide on-site application support.
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