This section is from the book "The Building Trades Pocketbook", by International Correspondence Schools. Also available from Amazon: Building Trades Pocketbook: a Handy Manual of reference on Building Construction.
Brickwork is generally estimated by the thousand brick laid in the wall, but measurements by the cubic yard and by the perch are also used. The following data will be useful in calculating the number of brick in a wall. For each superficial foot of wall. 1 in. (the width of 1 brick) in thickness, allow 7 1/2; brick; for a 9" (the width of 2 brick) wall, allow 15 brick; for a 13" (the width of 3 brick) wall, allow 22 1/2 brick; and so on, estimating 7 1/2 brick for each additional
4 in. in thickness of wall. The above figures are for the ordinary Eastern standard brick, which is about 8 1/4 X 4 X 2 1/4 in. in dimensions. If smaller brick are used, the figures will be increased proportionately. As brick vary considerably, a minimum size should be specified, when a large number are bought; otherwise, many more will be required than were figured on. If brickwork is estimated by the cubic yard, allow 500 brick to a yard. This figure is based on the use of the size of brick given above, with mortar joints not over 3/8 in. thick. If the joints are 1/8 in. thick, as in face brickwork, 1 cu. yd. will require about 575 brick. In making calculations of the number of brick required, an allowance of, say,
5 per cent, should be made for waste in breakage, etc.
The practice in regard to deductions for openings is not uniform throughout the country, but small openings are usually counted solid, as the cost of extra labor and the waste in working around these places balances that of the brickwork saved. All large openings, 100 sq. ft. or over in area, should be deducted.
When openings are measured solid, it is not usual to allow extra compensation for arches, pilasters, corbels, etc. Rubbed and ornamental brickwork should be measured separately, and charged for at a special rate.
Brick footings may be computed by the lineal foot. The following table, based on steps or offsets of one-quarter brick, or 2 in., for each course in the footing, gives the number of brick per lineal foot in footings for brick walls from 9 to 26 in. thick:
9" wall, footing 2 courses, 10 1/2. 18" wall, footing 4 courses, 39.
13" wall, footing 3 courses, 22 1/2. 22" wall, footing 5 courses, 60.
26" wall, footing 6 courses, 85 1/2.