How much self-levelling compound do I need?

It depends on the floor area and the depth of levelling required. As a guide, 1.8kg of compound covers 1m² at 1mm depth. A 20kg bag covers roughly 11m² at 1mm or 2.7m² at 4mm depth.

Do I need to prime the floor before self-levelling?

Yes, always prime the floor before applying self-levelling compound. The primer seals the substrate, prevents bubbles, and ensures proper bonding. One litre of primer typically covers 5m² of floor.

How long does self-levelling compound take to dry?

Foot traffic is usually possible after 4-6 hours for thin applications (1-3mm). Thicker pours (5-10mm) may need 12-24 hours. Full curing for floor coverings typically takes 24-48 hours depending on conditions.

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Floor Prep Calculator — Levelling Compound & Primer

Calculate self-levelling compound and primer quantities for floor preparation. Covers all floor conditions from minor levelling to deep fills.

Floor Area

Total area to level

Floor Condition

Current condition affects treatment needed

How We Calculate This

This calculator estimates self-levelling compound bags and primer litres based on your floor area and the depth of levelling required. Coverage rates are based on standard UK products.

The formula

Compound (kg) = Floor area × Depth (mm) × 1.8 kg/m²/mm

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Verify with your supplier.