How to calculate a floor screed: volume, cement and sand
Updated October 2, 2026
A screed levels a floor before tiles, parquet or a resin finish. Its quantity depends on the area, the thickness and the mix. Here is how to work out the volume and the materials of a traditional sand and cement screed.
1. Volume of the screed
Volume (m³) = area (m²) × thickness (m). Measure the thickness where the floor is lowest, not on average, and add about 5 % of waste.
- A bonded screed (on a clean slab) is usually thinner than a floating screed (on insulation).
- Follow the minimum thickness required for your floor type and the product used.
2. Materials per cubic metre
A traditional mix is often about 300 to 400 kg of cement per m³ of screed (350 kg is common), with roughly 1,400 kg of sand and around 200 litres of water, adjusted to obtain a damp, workable mortar.
Ready-to-use screed mixes and liquid (self-levelling) screeds have their own consumption per m² and per cm: read it on the bag or the technical sheet.
Worked example: 20 m², 5 cm thick
20 × 0.05 = 1.00 m³; with 5 % waste, 1.05 m³. At 350 kg/m³:
- Cement: 1.05 × 350 ≈ 368 kg, i.e. 11 bags of 35 kg.
- Sand: about 1,470 kg.
- Water: about 210 litres.
Before laying
Plan joints around the edges (perimeter strip) and respect the drying time before laying the floor covering: a common rule of thumb is about one week per centimetre for a traditional screed, but the product sheet prevails.
Then the tile calculator gives the tiles and boxes for the same room.
General information, checked at the date shown. It does not replace advice from a professional for your situation.