About this calculator
Already know how many bricks or blocks you are laying? This works out the cement and building sand directly.
How it’s calculated
Quantities per 1,000 standard bricks come from the Concrete Society of Southern Africa’s mix leaflet (SANS 2001-CM1 classes): Class II with common cement takes 150 kg of cement and 0.6 m³ of building sand, with masonry cement 200 kg and 0.55 m³; Class I with common cement takes 200 kg and 0.55 m³, with masonry cement (MC 22,5X) 350 kg and 0.5 m³. For blocks, the figure is scaled up by the volume of the 10 mm joints around each block compared with a standard brick, which slightly overstates mortar for hollow blocks laid on their face shells.
Worked example
With these inputs:
- Laying
- Bricks
- Number of units
- 1000
- Mortar mix (cement:sand)
- Class II, common cement (normal load-bearing walls)
- Waste allowance
- 10%
the result is:
- Mortar for 1,000 bricks
- 4 bags + 0.66 m³ sand
- Mortar
- Class II, common cement (normal load-bearing walls)
- Cement (50 kg bags)
- 4 bags
- Building sand
- 0.66 m³
- Mix by wheelbarrow
- 2 bags : 6 barrows sand
Tips from the trade
- Make only as much mortar as you can use in about 2 hours.
- Plasticiser makes the mix easier to work at 1:6, but don’t overdose it.
- Below the damp-proof course and in exposed walls, use a stronger mix.
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.