About this calculator
Cement and sand for a sand-cement floor screed, with AfriSam’s batch mix and the right thickness for each type of screed.
How it’s calculated
Volume = area × thickness × (1 + waste). AfriSam’s batch is one 50 kg bag of common cement and 130 L of moist sand (two 65 L wheelbarrows), which makes about 115 L of compacted screed. So bags = volume ÷ 0.115 m³, and sand = bags × 0.13 m³, rounded up to half cubes for ordering. At 25 mm, that is about 11 kg of cement and 28 L of sand per m², and AfriSam adds 10% for waste. Thickness depends on the type: monolithic about 25 mm (15 to 40 mm), bonded 25 to 50 mm, at least 50 mm on a damp-proof membrane and at least 70 mm on insulation boards.
Worked example
With these inputs:
- Measure by
- Length × width
- Length
- 4.5 m
- Width
- 3.6 m
- Screed thickness
- 25 mm
- Screed type
- Bonded (on hardened concrete)
- Waste allowance
- 10%
the result is:
- Screed materials
- 4 × 50 kg cement
- Volume (incl. waste)
- 0.45 m³
- Area
- 16.2 m²
- Batches (1 bag + 2 barrows of sand)
- 3.9
Tips from the trade
- Measure depth on a grid with a straightedge and average it. Don’t guess.
- For a bonded screed, brush off the laitance and clean the slab well before placing.
- Avoid stiff, semi-dry mixes laid with light screed boards. They are hard to compact and are a common cause of weak screeds.
Results are estimates for planning and pricing. Check quantities against your drawings, the manufacturer’s data and SANS 10400 (the National Building Regulations) and your local municipality before ordering.