About Fosroc Nitoflor EU5

Fosroc Nitoflor EU5 is a high-strength, self-smoothing epoxy underlay engineered to level and reprofile concrete floors before a final flooring system is installed. It is not a finished wearing surface in itself; rather, it is the corrective layer that turns an uneven, pitted or wavy slab into a sound, smooth and dimensionally true base. On many industrial sites the green concrete that comes off the form or the power-float never meets the flatness a high-build epoxy screed or self-levelling coating demands. Nitoflor EU5 bridges that gap. Supplied as a three-component pack – resin base, resin hardener and graded fillers – it is blended on site into a flowable mortar that is screeded out, then spike-rolled to release entrapped air and left to cure into a hard, low-absorption underlay. Once cured it is overcoated with a Fosroc topping such as Nitoflor FC140, Nitoflor FC150 or the self-levelling Nitoflor SL2000. The product is formulated to resist chemical attack and impact shock, which matters because the underlay carries the same service loads as the topping above it. For Indian contractors and consultants the appeal is practical: EU5 is laid across the 1.5 to 5 mm band, which covers the bulk of real-world level corrections without the cost of building up thickness in a premium wearing screed. Where a single application cannot take up the full depth, Fosroc’s wider Nitoflor EU range and local technical support cover greater build-ups. Space Arc Engineering stocks and applies Nitoflor EU5 as part of complete industrial flooring packages, pairing it with the correct primer and topping so the whole system performs as a unit rather than a set of loosely related layers.

The technical insight

Nitoflor EU5 is best understood as a sacrificial levelling course whose only job is to present a flat, sound, bondable plane to the wearing system that follows – so its mechanical numbers are deliberately matched to that role. The cured underlay develops 60 N/mm2 compressive strength, 25 N/mm2 flexural strength and 12 N/mm2 tensile strength at seven days (the specification clause sets the floor at 60 / 20 / 10 N/mm2), with nil water absorption to BS 1881 Part 122. Critically, its adhesion to a correctly prepared substrate is greater than the tensile strength of the concrete itself, meaning the weakest link in the build-up is the slab, not the epoxy bond line – exactly what a specifier wants from a levelling layer. The chemistry is a solvent-free, filled epoxy: emptying the hardener into the base, mixing to homogeneity, then slowly charging the graded fillers under continuous mixing for a further 3-5 minutes. At 35 degrees C the working window is a 70-minute pot life, initial hardness at 16 hours and full cure at 7 days. The overcoating window is the detail most often missed on site – the topping must go down after the EU5 is at least 18 hours old but no later than 48 hours, because beyond that the surface chemistry no longer offers a reliable inter-coat bond and mechanical or chemical re-keying becomes necessary. Substrate discipline governs everything: new slabs at least 21 days old, moisture content never above 5 percent, laitance removed by grit blasting, scabbling or grinding, and Nitoprime 25 used to seal highly absorbent concrete so the resin is not robbed from the bond line.

Where it is used

• Levelling and reprofiling uneven concrete slabs before a Fosroc epoxy wearing system is laid
• Smoothing power-floated or grit-blasted floors to receive Nitoflor FC140, FC150 or SL2000 toppings
• Taking up surface irregularities in the 1.5-5 mm range on new and old industrial concrete
• Providing a low-absorption, chemically resistant base course under epoxy screeds and coatings
• Restoring profile on worn or patch-repaired floors prior to recoating
• Preparing substrates in warehouses, factories, workshops and process areas for high-build flooring

Key advantages

• High strength – 60 N/mm2 compressive, 25 N/mm2 flexural and 12 N/mm2 tensile at 7 days
• Self-smoothing and seamless, producing a flat base with no joints other than those carried up from the substrate
• Nil water absorption to BS 1881 Part 122, giving a durable, moisture-tolerant underlay
• Adhesion greater than the tensile strength of the concrete, so the bond line is not the weak point
• Cost-effective levelling compared with building extra depth into a premium wearing screed
• Quick and easy to lay with standard squeegee, notched-trowel and spiked-roller technique
• Formulated to withstand chemical attack and impact shock, matching the service demands of the topping above
• Designed to integrate cleanly with the wider Fosroc Nitoflor flooring system and primers

Limitations & considerations

• Not a finished wearing surface – it must be overcoated with a Fosroc topping or coating
• Single application is limited to 1.5-5 mm; greater build-ups need other products in the Nitoflor EU range
• Tight overcoating window – the topping must be applied between 18 and 48 hours after laying EU5
• Short 70-minute pot life at 35 degrees C; mixed material must be used quickly and waste discarded
• Substrate moisture content must stay below 5 percent and the slab must be free of rising damp
• New concrete must be at least 21 days old before application
• Contains epoxy resins and hardeners that require gloves, goggles, ventilation and care during handling
• Highly absorbent substrates require priming with Nitoprime 25, adding a step and cost

Selection & best practice

Specifications

Industry use cases

How we position Fosroc Nitoflor EU5

Nitoflor EU5 sits at the substrate-preparation stage of the Fosroc flooring system rather than competing as a finished floor. Its natural partners are the toppings it is designed to receive – Nitoflor FC140 and Nitoflor FC150 high-performance epoxy coatings and the Nitoflor SL2000 self-levelling screed – with Nitoprime 25 as the priming option and Nitoflor Sol as the tool cleaner. Where a project needs greater build-up than 5 mm, the wider Nitoflor EU range and Fosroc’s epoxy mortars take over. Against the broader Indian market, contractors evaluating a levelling underlay will reasonably compare EU5 with Sika’s epoxy levelling and screed products (the Sikafloor range), MBCC/Master Builders Solutions epoxy underlays (formerly BASF MasterTop systems), and STP’s epoxy flooring line; Dr. Fixit (Pidilite) is strong in waterproofing and concrete repair but is less of a direct match for a high-build epoxy levelling course. EU5’s distinguishing pitch is the combination of high mechanical strength, nil water absorption and an adhesion that beats the concrete’s own tensile strength, all delivered as a cost-effective levelling layer that integrates cleanly with the rest of the Fosroc system. For Indian specifiers the deciding factors are usually total installed system cost, the availability of authorised application support, and confidence that the underlay and topping are warranted as a single build-up – which is where sourcing the complete stack through an authorised distributor and applicator like Space Arc Engineering carries weight.

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