Frequently Asked Questions

What are the differences between Fosroc Expocrete and the standard Nitoflor Epoxy SL self-levelling floor coating and when is the much more expensive Expocrete system justified?

Fosroc Expocrete and Nitoflor Epoxy SL are both epoxy-based industrial floor systems, but they occupy fundamentally different performance tiers and are justified by different project conditions. Nitoflor Epoxy SL is a two-component, 100 per cent solids epoxy self-levelling floor system applied at 2 to 4 mm DFT — at this thickness, it provides: excellent chemical resistance to oils, fuels, dilute acids, and alkalis; a smooth, seamless, hygienic surface that is easily cleaned; and good abrasion resistance for rubber-wheeled vehicle traffic and moderate pedestrian loads. The 2 to 4 mm DFT of Nitoflor Epoxy SL is sufficient for the vast majority of industrial, food processing, and commercial floor applications in India. Expocrete is a three-component epoxy-modified concrete overlay applied at 10 to 25 mm DFT — this much greater thickness provides performance that Nitoflor Epoxy SL cannot match in extreme conditions: abrasion resistance (the thick aggregate-filled matrix is not worn through by steel-wheeled vehicles or aggressive abrasive cleaning as quickly as a thin coating); impact resistance (the 15 mm thick Expocrete layer absorbs impact from dropped heavy objects that would crack and delaminate a 3 mm epoxy coating); and load distribution (the thicker stiff overlay distributes concentrated point loads from heavy forklift solid tyres over a larger substrate area, reducing substrate stress under the load). Expocrete is justified over Nitoflor Epoxy SL for: floors exposed to steel-wheeled trolleys or carts (steel wheels cut through thin epoxy coatings within months under heavy load); floors subject to frequent impact from heavy objects (battery changing areas, mould storage areas); and floors where the aggregate substrate concrete is of variable quality and the floor system must bridge minor substrate defects. The typical cost of Expocrete is 3 to 5 times higher per square metre than Nitoflor Epoxy SL — this premium is justified only where the extreme performance is genuinely required.

How is Fosroc Expocrete mixed and applied on site and does it require specialist equipment different from standard epoxy floor systems?

Fosroc Expocrete is a three-component system (epoxy base, epoxy hardener, and dry aggregate blend) that requires mixing of all three components in the correct ratio at the time of application — unlike standard two-component epoxy floor coatings where the base and hardener are mixed without aggregate addition. The mixing and application procedure for Expocrete requires more labour and is more physically demanding than standard epoxy floor systems: combine the epoxy base and hardener in the correct ratio (as supplied, following the TDS instructions) and mix the two liquid epoxy components thoroughly for 2 to 3 minutes until a uniform colour and consistency is achieved; immediately add the dry aggregate blend (supplied as a separate bag) to the mixed epoxy and mix the combined three components with a forced-action mixer or a heavy-duty drill and paddle mixer at low speed until a uniform, fully blended mixture is achieved — the aggregate must be evenly distributed throughout the epoxy matrix with no dry aggregate pockets or unmixed resin pools; the mixed Expocrete is placed on the primed concrete floor, spread with a serrated trowel to the required thickness, and compacted and finished with a steel float to a dense, smooth surface. The consistency of mixed Expocrete is similar to a stiff concrete mix rather than a flowing liquid — it requires physical effort to place and compact, unlike the self-levelling Nitoflor Epoxy SL that flows to a level surface under gravity. No specialist equipment beyond a heavy-duty drill mixer and steel trowels is required, but the mixing capacity must be sufficient for large pours — manual over-mixing of large batches is slow and physically demanding; a forced-action pan mixer (as used for screed and concrete mixing) is recommended for pours of more than 20 to 30 square metres per hour.

What is the required substrate preparation before applying Expocrete and can it be applied directly to an existing worn epoxy floor in a battery room that needs to be upgraded?

The substrate preparation requirements for Expocrete are the same high standard as for all Nitoflor floor systems applied to concrete — shot blasting or diamond grinding to remove all surface contaminants, weak concrete, and curing compound; the surface must be clean, dry, and free of all oil, grease, chemical contamination, and old coating materials before the epoxy primer is applied. However, for a battery room floor upgrade where the existing floor is an old, worn epoxy or acid-resistant coating that needs to be replaced with Expocrete, the substrate preparation must also address the removal of the old coating. If the old coating is well-bonded (no delamination, passes the adhesion tape test) but worn through in traffic areas, the preparation sequence is: abrasive blast or grind the entire old coating surface to a rough profile — the blasting must remove all old coating surface gloss and, in areas where the coating has worn through, must remove the laitance and weak surface concrete also; verify that the old coating or concrete surface passes a water absorption test after blasting (water absorbed within 30 seconds confirms adequate porosity for the primer to bond); apply Nitoprime 30 epoxy primer by roller to the entire area; allow to cure to touch-dry; apply Expocrete at the required thickness. If significant areas of the old coating are delaminating (hollow when tapped, lifting at edges), those areas must be completely removed (by grinding or scraping) down to sound concrete before the overall blast preparation and primer application. The battery acid contamination of old floors in battery rooms is a particular challenge — acid that has penetrated the concrete below the old coating can create a pH-lowered substrate that reduces epoxy adhesion. In this case, the concrete should be checked for depth of acid penetration (using pH paper on a water-wetted surface sample) and the surface layers should be ground back to a depth where the concrete pH is above 10 before applying the primer and Expocrete.