How it is calculated
The amount depends on the floor area, the average thickness and the product consumption per square metre per millimetre. The calculator uses 1.6 kg for self-levelling compound and 2.0 kg for sand-cement screed. Measure the thickness at several points with a laser or water level and use the average.
Dry mix, kg = area × thickness (mm) × consumption × (1 + reserve)Bags = dry mix ÷ bag weight, rounded upExample
A 4 × 3 m floor levelled with a 10 mm layer of self-levelling compound needs about 202 kg with a 5 % reserve — 9 bags of 25 kg.
Tips from practice
- Prime the base before pouring self-levelling compound, otherwise it loses water and cracks.
- Most self-levelling compounds work from 3 to 30 mm. Thicker layers need a screed first.
- Pour the whole room in one go; prepare enough bags and helpers.
Questions and answers
How much self-levelling compound per m²?
About 1.5–1.7 kg per square metre for each millimetre of thickness. For 10 mm that is about 16 kg per square metre.
What is the minimum screed thickness?
Sand-cement screed is usually at least 30–40 mm. Self-levelling compounds can be as thin as 3–5 mm.
How long before I can lay flooring?
It depends on the product and thickness: from a day for fast compounds to several weeks for thick sand-cement screed.
Found a mistake in a formula? Write to [email protected]