Frequently Asked Questions

What is the difference between a Nitoflor PU self-levelling system and a Nitoflor epoxy system?

The fundamental difference is in the chemistry and resulting mechanical properties of the cured coating. Epoxy systems (Nitoflor Epoxy SL) cure to a hard, rigid, glass-like surface with very high compressive strength and very good chemical resistance — ideal for areas with heavy forklift traffic and aggressive chemical exposure. Polyurethane systems (Nitoflor SL) cure to a semi-flexible surface with moderate compressive strength but much better flexibility, impact resistance, and thermal shock resistance. PU systems are preferred for areas with frequent temperature cycling (cleaning with hot water, cold store entrance zones), areas with impact loading (dropped pallets), or areas where substrate cracking is a risk. If in doubt, consult Space Arc Engineering — the choice depends on the specific performance requirements of the facility.

Can Nitoflor SL be applied to an existing ceramic tile floor?

Nitoflor SL can be applied over ceramic tiles in some circumstances, but the existing tiles must be in good condition — fully bonded to the substrate, with no hollow or cracked tiles — and the tile surface must be mechanically roughened (by grinding or shot blasting) to provide a bond profile. If any tiles are hollow, loose, or cracked, they must be removed and replaced with repair mortar before coating. The thickness of the Nitoflor SL system must be sufficient to bridge the grout lines (typically 3 to 4 mm) without telegraphing through to the surface. For critical hygienic areas, removing the tiles and coating the concrete substrate directly is preferable to coating over tiles, as any defective tile beneath the coating could lead to delamination of the entire floor finish later.

How should the concrete substrate be prepared before applying Nitoflor SL?

The concrete substrate must be mechanically prepared by shot blasting or diamond grinding to open the surface, remove all laitance, and provide a surface profile (CSP 3 to 5 per ICRI 310.2). The surface must be dry (maximum moisture content as specified by the primer data sheet — typically less than 4% by weight), structurally sound (minimum compressive strength 25 MPa), and free of all oil, grease, dust, curing compounds, and contamination. Any cracks, voids, or surface defects must be repaired before coating. A Fosroc PU-compatible primer (such as Nitoflor PE primer) must be applied to the prepared substrate before applying Nitoflor SL to ensure adhesion and to prevent moisture vapour from rising through the slab and causing blistering of the PU coating.