Turns a floor area and a screed thickness into sand, cement and the bags behind them.
Painting, tiling and finishes. 5 questions answered below, each with the arithmetic behind it and the limits of what the tool decides. Open the Screeding Calculator tool.
A screed estimate is a volume calculation wearing an area costume. The floor area is what you measure, but the order is sand and cement, and those follow the depth. That is why thickness is the first input the tool asks for and why a change from forty to seventy millimetres changes the material by three quarters on the same floor. The other half of the job is where the screed sits. A floor screed is ordered by volume, a wall render by area at a stated thickness, and a wearing surface over a sound base is thinner than a levelling screed over an uneven one. Keeping those cases apart is what stops a floor being priced at a render rate and a wall being ordered by the cubic metre.
A floor of sixty square metres at fifty millimetres needs three cubic metres of screed. At a one to four mix by volume, that is six tenths of a cubic metre of cement and two and four tenths of sand, which in bags of fifty kilogrammes is roughly nine hundred kilogrammes of cement, or eighteen bags, and about four tonnes of sand once its density is applied. Take the same floor to seventy five millimetres and the volume rises to four and a half cubic metres, the cement to twenty seven bags, and the sand to six tonnes. Same floor, same mix, no change in the drawing's intent, and a third more material, which is why thickness cannot sit inside a trade rate.
Multiply the floor area by the thickness to get a volume, then split that volume by the mix ratio into sand and cement. The calculator does both steps and expresses cement in the bag size sold in your market, with sand by volume or by tonne. Two things move the answer more than the area does: the thickness, which multiplies everything, and the mix, because a one to three screed uses noticeably more cement than a one to five for the same volume.
Between forty and seventy five millimetres is common for a levelling screed over a prepared base, with thinner sections used for a wearing surface over a sound floor. Below about forty millimetres the risk of curling and debonding rises, and above seventy five the material cost climbs quickly. Those are specification judgements, so the calculator asks for your thickness and shows what it consumes rather than choosing one for you.
No. Tile, stone, screed paint and any levelling compound above the screed are separate products with their own quantities and their own trades. The estimate covers the screed itself, which is what you order before the floor finish is even selected. Keeping them apart matters on a quotation, because a client changing the tile should not change the screed quantity, and mixing them makes that comparison impossible.
Enter the depth the specification calls for, in millimetres. If the base is uneven, the average depth is what governs the order, so measure the high and low points and use a figure that reflects the average rather than the minimum. The calculator shows the volume implied, which is the quickest way to sanity check whether the depth on a drawing meets the floor level you are trying to achieve.
Both, as separate surfaces, because they are measured and bought differently. A floor screed is a volume of sand and cement placed to a depth; a wall render is an area at a stated thickness, often with a different mix and a different finish. The calculator keeps the two apart so a wall is not ordered by the cubic metre and a floor is not priced from a render rate per square metre.