Screeding calculator
Enter the floor area and screed depth, choose the type, and get the volume plus cement bags and sand (or product bags for self-levelling). Handy for UFH floors where depth over the pipes decides everything.
Pricing the job? Open EstiMate free and these quantities go straight onto the materials list with your prices.
How it works out the quantities
- 1Volume = area × average depth. Depth is usually 65–75 mm for a bonded sand-cement screed, 40 mm minimum over insulation, 30 mm minimum cover over UFH pipes for liquid screeds.
- 2Sand-cement screed is a 1:3 to 1:4 mix; the calculator converts to 25 kg cement bags and sharp sand tonnage.
- 3Self-levelling compounds are priced by bag coverage at a given depth (typically 20–25 kg per m² at 10–12 mm).
- 4Liquid screeds are ordered by the m³ from the supplier — the volume figure is what you quote against.
Site tips before you order
- Check the depth in several places; an uneven slab can double the screed volume.
- Sand-cement over UFH needs 75 mm minimum and fibres or mesh — ask the UFH supplier.
- Allow drying time: about 1 mm per day for sand-cement up to 40 mm, slower above. It goes on the programme.
- Self-levelling over a rough slab often needs a primer and sometimes a two-pass approach.
Common questions
How thick should a floor screed be?
Bonded sand-cement 25–40 mm, unbonded 50 mm minimum, floating over insulation 65–75 mm (75 mm over UFH). Liquid screeds can be thinner — around 45–50 mm over UFH pipes.
How much sand and cement for 20 m² of screed at 65 mm?
1.3 m³ of screed — roughly 2 t of sharp sand and 18–20 bags of cement at 1:4, plus 10% waste. The calculator gives exact bags.
How many bags of self-levelling compound per m²?
About 2 bags (20 kg) per m² at 10 mm; a 5 mm skim uses one. Check the product's stated coverage.
Can I quote liquid screed with this?
Yes — the m³ figure is what the liquid-screed supplier prices against; add pumping and access as lines.
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