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Laying concrete floor screed
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Concrete Screed Calculator

Calculate screed volume, cement bags, sand and drying times for sand & cement, liquid and fast-track screed systems.

Concrete Screed Calculator

Add each area, choose your screed type and thickness, and get volumes, materials and drying times

Metric (m) Imperial (ft / in)

Areas

Unbonded on insulation: 65-75mm • Bonded to concrete: 25-40mm • UFH: min 65mm over pipes
5%
Allow 5-10% for uneven sub-floors and mixing losses

Job Costing

Enter costs in your local currency.

Results

Total Area
-
m²
Screed Volume
-
m³
Cement Bags
-
x 25kg bags
Sand
-
tonnes

Estimated Drying / Curing Times

-
Walk on
-
Light use / tiling
-
Full cure / floor covering

Drying times are estimates only and depend on temperature, humidity and ventilation. Always check with your screed supplier.

Area Breakdown

Area Floor Area Volume Cement Bags Sand (t)

Screed Type Guide

  • Sand & cement (site mixed) - Traditional 1:3 to 1:4.5 mix. Most common in UK domestic. Needs 24-48h before walking on, weeks to fully dry.
  • Sand & cement (bagged) - Pre-mixed for convenience. Same drying characteristics as site-mixed. Good for small areas or repairs.
  • Liquid anhydrite - Calcium sulphate-based. Pump-applied, self-levelling. Thinner minimum depths. Cannot be used in wet rooms. Needs priming before tiling.
  • Liquid cement - Cementitious flowing screed. Self-levelling, pump-applied. Can be used in wet rooms. Faster than traditional but slower than anhydrite.
  • Fast-track - Walk on in 4-6 hours. Tile in 24-48h. Premium cost but critical path savings on fast build programmes.

Thickness Guide

  • Bonded to concrete slab - 25-40mm. Must be mechanically keyed and primed.
  • Unbonded (on DPM) - 50-75mm minimum. Laid on a polythene slip membrane.
  • Floating (on insulation) - 65-75mm minimum for sand & cement. 35-45mm for liquid screed.
  • Underfloor heating - Min 65mm over pipe centres for sand & cement. Min 30-45mm for liquid screed. Check UFH supplier spec.
  • Liquid screed minimum - 35mm unbonded, 25mm bonded. Much thinner than traditional screed.

Drying Tips

Sand & cement screed needs adequate ventilation to dry. Open windows and use dehumidifiers - do not use direct heat in the first week.

Anhydrite screed must be forced-dried with heating and ventilation before tiling. A priming coat (diluted PVA or specialist primer) is essential before applying adhesive.

Test moisture content with a hygrometer before laying any floor covering - target below 75% RH for most adhesives and floor coverings.

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