How much screed do I need?
Enter the floor area and screed depth and we'll work out the volume and cost — with the calculation shown. Screed, like concrete, is all about area × depth.
materials per m² at 50mm.
| Sand & cement floor screed (50mm) | 21 m² | £189 |
- 1Floor area: 20 m²
- 2Usage rate: materials per m² at 50mm
- 3Allowing for waste: 20 × 1 × 1.05 waste = 21 m²
- 4Quantity: 21 m² @ £9 each
- Material cost only — labour is estimated separately in the schedule.
- Indicative trade-counter price; confirm with a current supplier quote.
How to work out screed quantities
- 1Measure the floor area
Length × width of the floor in metres. A 5 m × 4 m room is 20 m².
- 2Choose the depth
A bonded sand-and-cement screed is often 40–50 mm; unbonded or floating screeds (over insulation or underfloor heating) are thicker, around 65–75 mm.
- 3Area × depth = volume
20 m² at 50 mm is 20 × 0.05 = 1.0 m³ of screed. Add ~5–10% for waste and levelling.
- 4Match to the floor build-up
Screed over underfloor heating pipes needs the right cover depth — check the UFH system's minimum before you set the level.
Screed and concrete are estimated the same way — area times depth — but the depth is where screed catches people out: a floating screed or one over underfloor heating is far thicker than a simple bonded topping, and getting the cover wrong over UFH pipes is an expensive mistake to fix.
Screed depths by application (indicative)
| Application | Typical depth | Volume guide |
|---|---|---|
| Bonded screed | 40–50 mm | 0.04–0.05 m³ per m² |
| Unbonded screed | 50 mm+ | 0.05 m³ per m² |
| Floating (over insulation) | 65–75 mm | 0.065–0.075 m³ per m² |
| Over underfloor heating | to system spec | check UFH minimum |
Liquid/flow screeds differ from traditional sand-and-cement. 1 m³ of screed is roughly 2 tonnes. Confirm with quotes.
Frequently asked questions
How much screed do I need?+
Multiply the floor area by the depth in metres. A 20 m² floor at 50 mm needs 20 × 0.05 = 1.0 m³ of screed, plus about 5–10% for waste and levelling.
How thick should floor screed be?+
A bonded sand-and-cement screed is typically 40–50 mm; a floating screed over insulation or underfloor heating is thicker at around 65–75 mm. Always meet the minimum cover for any UFH pipes.
How much does screed cost?+
Traditional screed is priced by volume (materials plus labour); liquid screeds are often quoted per m² at a set depth. The calculator estimates the quantity and cost from your area and depth.
Related tools & guides
Want to know how these figures are calculated? See our cost methodology.
Cost figures shown are indicative estimates, not quotations. You are responsible for verifying all costs (obtain contractor quotes) and any figures submitted to a lender. ScopeWise is a documentation tool, not financial, tax, structural or planning advice. HMO compliance prompts are guidance only — confirm requirements with your local council, as standards and licensing vary by authority.