Where 48.5 bricks per square metre comes from
A standard Australian brick is 230 mm long, 110 mm wide and 76 mm high. In the wall it sits with a 10 mm mortar joint beside it and a 10 mm bed joint under it, so each brick occupies 240 × 86 mm of wall face. That is 0.02064 square metres per brick, and one divided by that is 48.45 bricks per square metre. Bricklayers round it to 48.5, or to 50 when they are quoting on the back of a card.
bricks per m² = 1 ÷ ((brick length + joint) × (brick height + joint))
= 1 ÷ (0.240 × 0.086) = 48.5
Other sizes follow the same rule. A 50 mm slimline brick needs 69 per square metre, a 290 mm linear brick 33, and a 400 mm long-format brick about 24. Blocks are on their own calculator.
Deduct openings, then add waste
Measure the gross wall area, take away the doors and windows, and multiply by the bricks per square metre. Then add waste. Five percent covers a plain wall with a few corners. Ten percent is more realistic for a wall full of openings, piers, steps in the footing and a diagonal at the gable, because every cut brick throws away a piece and some bricks arrive broken. For a cavity wall in double brick, both skins count, so the total doubles and you add wall ties as well.
| Wall | Net area | Bricks | With 5% | Pallets of 500 |
|---|---|---|---|---|
| Garden wall 6 × 1.2 m, single skin | 7.2 m² | 349 | 367 | 1 |
| Garage 18 m × 2.7 m, one door 5.4 m² | 43.2 m² | 2,093 | 2,198 | 5 |
| House veneer 42 m × 2.7 m, openings 22 m² | 91.4 m² | 4,428 | 4,650 | 10 |
| Same house in double brick | 91.4 m² | 8,856 | 9,299 | 19 |
Mortar, sand and cement
Rules of thumb here are only ever approximate, because the amount of mortar depends on joint size, the brick's frog and cores, and how much ends up on the ground. A commonly used allowance is about half a cubic metre of mixed mortar per thousand standard bricks. To make that you need more sand than the finished volume, because sand bulks and the cement fills the gaps, so allow 0.6 to 0.7 cubic metres of bricklayer's sand, about six 20 kg bags of cement and three of hydrated lime per thousand bricks for a 1:1:6 mix. If your bricklayer uses a different mix or a premixed mortar, use their figures.
Wall ties
Cavity walls need ties between the two skins, normally at 600 mm centres horizontally and vertically, which is about 2.8 per square metre, with extra rows around openings and at the top of the wall. Brick veneer over a timber or steel frame also needs ties, at the same sort of spacing, screwed or nailed to the studs. The calculator shows a tie count for double brick; for veneer, use the same area figure.
Worked example
A brick veneer garage 6 × 9 m and 2.7 m high has 30 m of wall and a gross area of 81 m². Take out a 5.4 m² roller door and a 1.8 m² personal door and the net area is 73.8 m². At 48.5 per square metre that is 3,580 bricks. With 5 percent waste, 3,759, which is eight pallets of 500. Mortar about 1.9 m³, which means roughly 2.4 m³ of sand, 23 bags of cement and 12 of lime.
Common questions
How many bricks per m² in Australia?
48.5 standard bricks per square metre with 10 mm joints. Double brick uses twice that.
How many bricks on a pallet?
400 to 500 depending on the maker. Bricks are delivered in whole pallets.
How much waste on bricks?
5 percent for plain walls, up to 10 percent with lots of cuts and openings. Order the whole job from one batch.
How much mortar for 1000 bricks?
About 0.5 m³ mixed, which is roughly 0.65 m³ of sand, six bags of cement and three of lime for 1:1:6.
Quantities only. Mortar mix, tie spacing, lintels and any structural brickwork follow AS 3700 and AS 4773, the brick manufacturer's guides and your engineer.