Screed calculator

How the liquid screed calculator works

Screed is ordered by volume, not by area. The sum is simple: floor area in square metres multiplied by depth in metres. A 40 m² extension at 50mm is 2 m³; the same room at 65mm over underfloor heating is 2.6 m³. That jump is why depth matters more than most people expect when they compare quotes.

The margin covers what drawings leave out. Bases are rarely dead level, insulation boards leave small steps, and the edge strip and any pipe runs change the volume at the edges. On a well-prepared floor a small allowance is usually enough; on an older slab with dips, a larger one is sensible.

Typical depths to enter

• Liquid screed bonded to a sound slab: from 30mm.
• Liquid screed unbonded over a membrane: from 35–40mm.
• Over underfloor heating pipes: usually 50–65mm in total, to give the pipes proper cover.
• Sand and cement screed: usually laid thicker; use the depth on your specification.

From volume to a screed cost

This floor screed calculator gives volume only. A screed cost depends on the mix, the depth, the size of the floor, access for the pump and whether there is underfloor heating, so we price each job on a written quote. Read the floor screed cost guide for what moves the price, or liquid screed cost per m³ for how volume and depth feed into it.

Not sure which screed suits your floor? Compare anhydrite screed, sand and cement screed and screed over underfloor heating.