Frequently Asked Questions

When should Nitoflor Uremax be specified instead of Nitoflor Epoxy SL for an industrial floor and what are the key differences?

The choice between Nitoflor Uremax (polyurethane) and Nitoflor Epoxy SL (epoxy self-levelling) for an industrial floor depends on the specific performance requirements of the facility. The primary differences are: UV stability (Nitoflor Uremax is UV stable and maintains its colour and gloss in sunlit environments; Nitoflor Epoxy SL yellows and chalks under UV exposure, making it unsuitable for external applications or for floor areas receiving direct sunlight through skylights or windows); flexibility (Nitoflor Uremax has a more flexible cured matrix than the harder, more rigid Nitoflor Epoxy SL, making it better for floors with residual shrinkage movement, thermal cycling, or vibration loading that could crack a more rigid epoxy); and impact resistance (the flexibility of PU gives Nitoflor Uremax better impact and indentation resistance than epoxy, which tends to crack under sharp point impacts at heavy loads). Nitoflor Epoxy SL is preferred for: indoor environments without UV exposure; floors where the highest compressive strength and chemical resistance under heavy static loads is needed; floors where the highest gloss and smoothest self-levelling surface is required for aesthetic or hygiene reasons; and where budget is a consideration (PU coatings are generally more expensive than epoxy). Nitoflor Uremax is preferred for: external or UV-exposed applications; floors with thermal cycling or movement; food and pharmaceutical facilities where colour stability is important; and high-traffic areas where the flexibility of PU provides better long-term durability against impact damage.

What is the minimum temperature for applying Nitoflor Uremax and how does Indian summer heat affect the application and curing?

Nitoflor Uremax requires the concrete substrate and ambient temperature to be above approximately 10 to 12 degrees Celsius for application and curing — temperatures below this minimum cause the polyurethane cure reaction to proceed too slowly, and in extreme cold the PU may not cure properly at all. This minimum temperature is never a constraint in India. In Indian summer conditions (ambient temperature 35 to 45 degrees Celsius, concrete surface temperature potentially higher), the polyurethane cure reaction is significantly accelerated and the pot life of the mixed material is shortened — typically from 30 to 45 minutes at 25 degrees Celsius to 15 to 20 minutes at 35 degrees Celsius. This means that the working area covered in each mixed batch must be smaller in summer, and the material must be applied and spread more quickly before it begins to gel. Additionally, very high concrete surface temperatures (above 40 degrees Celsius) can cause bubbling and pinhole defects in the applied coating — these are caused by air and moisture vapour in the hot concrete expanding and escaping through the coating during the early cure phase. Best practice for Nitoflor Uremax application in Indian summer is to apply during the early morning (6 to 10 am) and late evening (after 6 pm) when concrete surface temperatures are lower; to avoid application when direct sunlight is heating the floor surface; and to run the facility air conditioning (if available) to lower the floor temperature before application.

Does Nitoflor Uremax need the same substrate preparation as Nitoflor Epoxy SL and are the priming requirements the same?

Yes — Nitoflor Uremax requires the same standard of concrete substrate preparation as the Nitoflor Epoxy SL system: the concrete must be clean, dry, sound, and with a mechanically prepared surface providing adequate porosity and profile for the PU coating to bond to. Shot blasting or grinding to remove laitance, contamination, and the weak surface zone is essential for all applied floor coatings, including both epoxy and polyurethane systems. The priming requirement for Nitoflor Uremax is typically a polyurethane-compatible primer — Fosroc supplies a specific primer for the Uremax system (confirm the current primer grade with Fosroc technical support or Space Arc Engineering, as the primer specification may differ from the Nitoprime 25 epoxy primer used under Nitoflor Epoxy SL). The PU primer must be compatible with both the concrete substrate and the Uremax topcoat — using an epoxy primer under a PU topcoat is possible in some system combinations (the epoxy primer seals and strengthens the concrete surface, providing a sound base for the PU) but must be confirmed to be system-compatible with Nitoflor Uremax in the specific product version supplied. The moisture content requirement for the concrete is similar to epoxy systems — below 75 per cent relative humidity measured at 25 mm depth. Very wet concrete is particularly important to avoid under polyurethane coatings because moisture reacts with isocyanate groups in PU hardeners, producing carbon dioxide gas that causes bubbling and pinhole defects in the cured coating.