Floor Prep Calculator — Levelling Compound & Primer

It depends on the floor area and the depth of levelling required. This calculator uses 1.6 kg/m² per mm of depth (Mapei Ultraplan Eco 3210 data sheet), so a 20kg bag covers about 12.5m² at 1mm or roughly 3.1m² at 4mm. Rates vary by product — typically 1.4 to 1.86 kg/m²/mm (Ardex K15 1.4, Setcrete up to 1.86) — so always confirm against your product's data sheet.

Yes, always prime the floor before applying self-levelling compound. The primer seals the substrate, prevents pinholing and bubbles, and ensures proper bonding. Coverage varies widely: ready-to-use floor primers often cover around 10 m²/L neat on non-absorbent surfaces and up to 20 m²/L diluted on absorbent ones (e.g. Setcrete Acrylic Primer). The calculator defaults to a conservative 5 m²/L — adjust it to your tin's stated figure.

It depends on the product, not just the depth. Modern rapid-set compounds usually accept foot traffic in about 1-2 hours and floorcoverings from 4-6 hours, largely regardless of thickness (for example Mapei Ultraplan is ready for floorcoverings after roughly 12 hours irrespective of depth, while Setcrete High Performance allows walk-on in 1-2 hours and floorcoverings from 6 hours). Standard (non-rapid) compounds dry more slowly and thicker pours take longer to fully cure. The drying time shown here is a conservative indicative estimate only — always follow your product's data sheet.