Before masonry work starts you need to know how many blocks or bricks to buy. Too few means another trip to the store, too many means money sitting idle.
Formula
- Wall area = length × height − area of windows and doors
- Blocks per m² = 1 / ((block length + joint) × (block height + joint))
- Blocks needed = wall area × blocks per m² × (1 + waste %)
For example a 600 × 200 mm block with a 10 mm joint gives about 8 blocks per square metre. Add around 5 % for waste.
Mortar
Mortar volume is roughly the wall volume minus the block volume. Thin-joint (glued) masonry uses far less mortar.
Use the calculator
All of this is done in our block calculator. For reinforcement see the rebar calculator.
If the project is bigger or you have drawings, order an estimate – a labour and materials budget from €20.