Bricks per square foot is not a property of bricks. It is the result of dividing a square foot by the area of the brick and its joint, so it changes with both.
Area per brick = (brick length + joint) × (brick height + joint)
Bricks per sq ft = 144 ÷ area per brick (in square inches)
Modular brick, worked by hand
Modular brick is about 7⅝ × 2¼ in on the face. With a ⅜ in joint the module is 8 × 2⅝ in, which is 21 sq in. Dividing 144 by 21 gives about 6.86. Glen-Gery, a brick manufacturer, publishes the same figure for modular brick with ⅜ in joints, along with 6.55 for standard brick and 6.00 for Roman.
The planner reproduces this. For a 100 sq ft wall and no waste, modular brick with a ⅜ in joint needs 685.7 bricks, which is 6.86 per square foot.
| Brick (face, joint) | Per 100 sq ft | Per sq ft |
|---|---|---|
| Modular, 7⅝ × 2¼ in, ⅜ in joint | 685.7 bricks | 6.86 |
| Standard, 8 × 2¼ in, ⅜ in joint | 655 bricks | 6.55 |
| Roman, 11⅝ × 1⅝ in, ⅜ in joint | 600 bricks | 6.00 |
| Modular, ½ in joint | 644.5 bricks | 6.45 |
This example assumes
- Face 7⅝ × 2¼ in, ⅜ in joint
- No waste allowance, so the figure is the pure per-square-foot count
- A 10 × 10 ft wall of 100 sq ft
Wider joints use fewer bricks
A wider mortar joint spreads the bricks out. The same modular brick with a ½ in joint needs 644.5 bricks, which is 6.45 per square foot, because each brick now claims a larger module. If your joints are not ⅜ in, enter the real width.
Roman brick, which is long and thin (11⅝ × 1⅝ in on the face), comes to 600 bricks on the same wall, or 6.00 per square foot.
Published figures differ a little
Glen-Gery’s own pages are not fully consistent. One lists 6.86 for modular brick and another lists 6.75. The difference is small, and it is the reason to confirm the number with the manufacturer of the brick you are buying. The arithmetic above is what shows where 6.86 comes from.
What changes the estimate?
- Brick face size, which varies by type and manufacturer
- Joint width, which changes the module
- The waste allowance, which is separate from this per-square-foot count
- Openings, which are subtracted from the wall area first
For a whole wall with an opening and an allowance, see how many bricks for a wall.