The number of standard-size brick (8 by 3¾ by 2¼ inches) required
to build a straight chimney having only two or three flues can be
estimated by drawing the flue lining to scale and then drawing lines 4
inches to 8 inches outside of the lining depending on the thickness of
the brick walls. Lay out 4- by 8-inch rectangles in the space between the
lining and the outside lines to determine how many brick are needed per
course.
For example, 15½ brick are needed for each course of the chimney in
figure 9. Assuming the height is 30 feet and one-half-inch mortar joints
are used, also that there are 4½ courses per foot, there would be 135
courses. Therefore, 135 multiplied by 15½ equals 2,092 brick; about
100 more will be needed to make the lower portion solid, or 2,200 brick
in all.
A more general method of estimating that is applicable to more complex
structures is given on page 43. Methods of determining the quantity of
mortar materials, labor, and cost are also given and can be applied to
this example.