The following table gives the number of standard size brick per square foot of wall surface, 4 inches or one brick thick, estimated for different widths of mortar joint up to 3/4-inch:
TABLE 1
Number of Face Brick per Square Foot
| Joint | 1/8" | 1/4" | 3/8" | 1/2" | 5/8" | 3/4" |
| No. of Brick | 71/2 | 7 | 61/2 | 61/8 | 53/4 | 51/2 |
General Rule
The method employed in getting these numbers is very simple and may be applied to any sized brick and joint whatsoever. Thus, take the brick given in the accompanying illustration ([Fig. 58]) and let us use, say, a 3/8" mortar joint. This makes a length of 81/4" + 3/8", or 85/8" and a height of 23/8" + 3/8" or 23/4". Hence, the total area occupied in the wall by this brick, with its mortar joint, is 85/8" × 23/4". You can work this out by tractions, thus, 69/8 × 11/4 = 759/32; or by decimals, thus, 8.625 × 2. 75 = 23.72, the area of the brick and mortar joint in square inches.
Fig. 58. Brick and Mortar Joint
In either case, to get the number of brick required per square foot you, of course, divide into 144, the number of square inches in a square foot. That is, 144 ÷ 759/32 = 144 × 32/759 = 4608/759 = 654/759 or about 61/15. Or divide 144 by 23.72 and you get 6.07, which amounts to your previous figure. In estimating the whole number of brick you need, use no fraction less than the eighth next above the fraction obtained in your number for the square foot. Thus in the present example, you will count on using 61/8 brick for every square foot of wall area.