TryBuildCalc

Tile Base Screed Calculator (Screed Before Tile Installation)

Estimate screed materials before tiling.

Inputs

ℹ️Typical: 38-50 mm (bonded/unbonded), 65-75 mm (floating/underfloor heating)

Cost

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For 9.00 of floor area, you need approximately 4 cement bags and 0.50 of sand.

Screed Volume

Floor area: 9.00

Wet volume: 0.450

Dry volume (×1.33): 0.599

Materials

Cement: 3.6 bags — buy 4 bags

Sand: 0.503 (~0.80 metric tons)

Sand tonnage is approximate, using 1.6 tons/m³ average bulk density.

Order Summary — Theoretical vs. Order Quantity

MaterialTheoreticalOrder Quantity
Cement3.5 bags4 bags (whole)
Sand0.4790.503

Theoretical = before wastage. Order Quantity = after your 5.0% wastage allowance (cement rounded up to a whole bag).

Assumptions Used

Dry volume factor: 1.33 | Cement bag: 50 kg / 0.0347 m³ | Wastage applied once to cement bags and sand volume.

Bonded, unbonded, or floating — not sure which screed type applies here? Floor Screed Guide →

Tiling this floor once the screed has cured and dried? Tile Calculator →

Floor Screed VisualizationScreed LayerBase Slab / PCC50 mmLength: 3 mWidth: 3 mDiagram simplified for clarity (not to scale)

Looking for the verification checklist, reference tables, tips, or common mistakes?See the complete Floor Screed Calculator.

Tile base screed material estimate

This page is set up for the common screed-before-tile scenario — a level, flat base is essential for a good tile installation, and this pre-fills the standard 50mm/1:4 combination.

Edit the floor dimensions or thickness above to match your project, and the material breakdown updates from the active values.

  • Screeds receiving ceramic or vitrified tile need ±3mm flatness under a 3m straightedge.
  • Allow the screed to dry fully before tiling — roughly 1 day per mm of thickness for the first 50mm.
  • After this calculator, use the Tile Calculator and Tile Adhesive Calculator for the finish layer above.

Floor Screed Formula: How Is Cement and Sand Quantity Calculated?

Screed quantity is calculated from floor area and thickness, converted into dry volume, then distributed according to the cement:sand mix ratio.

Step 1 — Floor Area & Wet Volume

Floor Area = Length × Width

Wet Volume = Floor Area × Screed Thickness

Floor area is the plan area to be screeded. Wet volume is the actual mixed-screed volume needed to cover that area at the specified thickness.

Step 2 — Dry Volume Correction

Dry Volume = Wet Volume × 1.33

The dry volume factor accounts for sand bulking, voids between materials, and practical construction losses during mixing and application. Screed uses 1.33 rather than concrete's 1.54 because it contains no coarse aggregate.

Step 3 — Mix Ratio Distribution

Cement Volume = Dry Volume × (Cement Part ÷ Total Parts)

Sand Volume = Dry Volume × (Sand Part ÷ Total Parts)

Dry screed volume is divided according to the selected cement:sand mix ratio — 1:3 (heavy-duty industrial), 1:4 (standard), or 1:5 (light leveling only). Total Parts is the sum of both ratio parts.

Step 4 — Cement Bags Conversion

Cement Bags = Cement Volume ÷ 0.0347 m³/bag (50 kg bags)

One standard cement bag (50 kg) occupies approximately 0.0347 cubic metres. This conversion translates calculated cement volume into practical material procurement quantities.

Step 5 — Final Quantity with Wastage

Final Cement Bags = Cement Bags × (1 + Wastage %), rounded up to a whole bag

Final Sand Volume = Sand Volume × (1 + Wastage %)

Wastage is applied to both cement bags and sand volume for the practical order quantity — shown separately from the theoretical pre-wastage figures in the result card.

Worked Example

This example walks through your current inputs above, using the same steps as the Formula section.

Input Values Used

InputValueWhy it is used
Length × width3m × 3mSets the floor area to be screeded
Thickness / mix ratio / wastage50mm, 1:4, 5% wastageSets wet volume and splits dry volume into cement/sand

Step 1 — Area & Volume

CalculationSubstitutionResult
Floor area3m × 3m9.00
Wet volume9.00 × 50mm0.450
Dry volume0.450 × 1.330.599

Step 2 — Cement & Sand

MaterialTheoreticalOrder Quantity
Cement3.5 bags4 bags (whole)
Sand0.4790.503

Therefore, for 9.00 m² of floor at 50mm screed thickness and a 1:4 mix, you need approximately 4 cement bags and 0.50 of sand.

Disclaimer: This calculator provides approximate results for planning and estimation purposes only. Actual requirements may vary based on site conditions, materials, workmanship, and local building regulations. Always consult a qualified engineer, architect, or construction professional before making final decisions.

FAQ

±3mm under a 3m straightedge for ceramic or vitrified tile — tighter than the ±5mm tolerance for resilient flooring or ±10mm for carpet. Thin-bed tile adhesive is not a levelling compound, so the screed itself must meet this tolerance.
Screed must be fully dry, not just cured — roughly 1 day per mm thickness for the first 50mm, then 2 days per mm above that. A 50mm screed needs approximately 50 days. Tiling over a wet screed causes adhesive failure and moisture damage to the tile finish.