Formula
Bricks per square foot are 144 divided by the face module, brick length plus the joint, times brick height plus the joint. The count is that rate times the net wall area, times one plus the waste, then rounded up. Running bond is the assumption. A different bond changes the cuts.
bricks / ft² = 144 / ((L + j) × (H + j))
mortar / brick = ((L + j)(H + j) − L × H) × depth
bags = mortar with waste ÷ bag yield
Mortar here is the bed and head joint of a single wythe, the brick depth times the joint area around one face. It is not a collar joint and not a cavity. Real waste depends on the bond, the cuts, and how the mason lays the joint. BIA also publishes a different specified size when the joint is 1/2 inch. The fields stay on the 3/8 inch specified size until you edit them.
Worked examples
Modular, 20 × 8 ft, 3/8 in joint, 5 percent waste. 6.857 per square foot, 1,098 bricks net, 1,152 with waste. Mortar about 8.85 cubic feet, 11.06 with 25 percent waste, 19 bags at 0.6 cubic feet.
The same wall with a 3 × 7 ft door. 139 square feet, 1,001 bricks with 5 percent waste.
Utility, 100 square feet, 10 percent waste. 3.00 per square foot, 300 net, 330 with waste.
Reference
Specified dimensions from BIA Technical Note 10 for a 3/8 inch joint. Width × height × length, in the stretcher position. Depth on this page is that width.
| Designation | Specified size | Coursing note |
|---|---|---|
| Modular | 3.625 × 2.25 × 7.625 in | BIA Table 1. 3 courses = 8 in with a 3/8 in joint. |
| Standard | 3.625 × 2.25 × 8 in | BIA Table 2, non-modular. 3 courses = 8 in with a 3/8 in joint. |
| Engineer modular | 3.625 × 2.8125 × 7.625 in | BIA Table 1, Engineer Modular. Height is 2-13/16 in. 5 courses = 16 in. |
| Norman | 3.625 × 2.25 × 11.625 in | BIA Table 1. 3 courses = 8 in with a 3/8 in joint. |
| Roman | 3.625 × 1.625 × 11.625 in | BIA Table 1. 2 courses = 4 in with a 3/8 in joint. |
| Utility | 3.625 × 3.625 × 11.625 in | BIA Table 1. 1 course = 4 in with a 3/8 in joint. |
Questions
How many bricks per square foot?
A modular brick, 7-5/8 by 2-1/4 inches, with a 3/8 inch joint, covers 21 square inches. 144 divided by 21 is 6.857 bricks per square foot, about 6,857 per 1,000 square feet. The joint changes the count.
How many bricks do I need for a 20 by 8 foot wall?
That is 160 square feet. Modular brick at a 3/8 inch joint is 1,098 bricks before waste and 1,152 with a 5 percent allowance. A 3 by 7 foot door drops the net area to 139 square feet and the order to 1,001 bricks with the same waste.
How much mortar for 1,000 bricks?
For this modular 3/8 inch case the joint volume is about 8.06 cubic feet before waste. That is an estimate for a single wythe and a running bond. The bag yield and the mason’s practice change it.
How many bags of mortar per 100 bricks?
The same modular joint is about 0.81 cubic feet per 100 bricks before waste. At 0.6 cubic feet per bag that is 2 bags. With a 25 percent allowance it is still 2 bags. Check the bag you buy.
How do you subtract windows and doors?
Measure each opening and subtract width times height from the wall area before you multiply by bricks per square foot. Measure the masonry opening, not the trim.
What size is a standard brick?
In BIA Technical Note 10, Table 2, a standard brick specified for a 3/8 inch joint is 3-5/8 by 2-1/4 by 8 inches, width by height by length. Modular is 3-5/8 by 2-1/4 by 7-5/8. The name on a pallet can differ. Order by the dimensions.
How much waste should I allow?
Five percent is the opening figure for a straight wall. Ten percent is a planning range when there are cuts and breakage. Corners, a bond other than running bond, and a complicated opening pattern can use more. It is an allowance, not a rule.
Sources
- Brick Industry Association, Technical Note 10, Dimensioning and Estimating Brick Masonry. Table 1 modular sizes and Table 2 non-modular sizes, specified dimensions for a 3/8 inch joint. ASTM C216 and ASTM C652 are the standards that note cites for facing brick and hollow brick tolerances. This page uses the specified dimensions, not a measured pallet.
- The brick count and the mortar volume are estimating formulas for a single wythe and a running bond. They are not a structural design.