How the calculator works
Volume is the floor area multiplied by the depth: area in m² × depth in mm ÷ 1,000 = m³. The waste allowance is then added.
Sand and cement: laid screed weighs roughly 2,100kg per m³. In a 1:4 mix by weight, about one fifth is cement and four fifths sharp sand, so each m³ needs about 420kg of cement (roughly 17 bags of 25kg) and 1.7 tonnes of sand.
Liquid screed is ordered by the cubic metre from the plant, so the calculator rounds the volume up to the nearest 0.5m³.
Drying time uses the common rule of thumb of one day per millimetre for the first 40mm and two days per millimetre beyond that, in good drying conditions. Liquid screed can often be force dried with underfloor heating, so it may be ready sooner. Read how long screed takes to dry before booking your flooring.
Prices use the 2026 supply and lay ranges published by MyJobQuote: about £18 to £25 per m² for sand and cement and £24 to £31 per m² for liquid screed. Our floor screeding cost guide explains what moves a price up or down.
Choosing the right depth
Floating sand and cement screed over insulation is typically at least 65mm in homes and 75mm in commercial buildings. Liquid screed can be from about 35mm, with at least 25mm of cover over underfloor heating pipes. Our screed thickness guide has the full figures.
