Figure 7-37.—Typical sizes and shapes of concrete masonry units.
in figure 7-37. Concrete unit sizes are usually
referred to by their nominal dimensions. A unit
measuring 7 5/8 in. wide, 7 5/8 in. high, and 15
5/8 in. long is referred to as an 8- by 8- by 16-in.
unit. When it is laid in a wall with 3/8-in. mortar
joints, the unit will occupy a space 16 in. long and
8 in. high. Besides the basic 8- by 8- by 16-in.
units, the illustration shows a smaller partition
unit and other units that are used much as cut
brick are in brick masonry.
The corner unit is laid at a corner or at some
similar point where a smooth, rather than a
recessed, end is required. The header unit is used
in a backing course placed behind a brick face tier
header course. Part of the block is cut away to
admit the brick headers. The uses of the other
shapes shown are self-evident. Besides the shapes
shown in figure 7-37, a number of smaller shapes
for various special purposes are available. Units
may be cut to the desired shapes with a bolster
or, more conveniently and accurately, with a
power-driven masonry saw.
The sides and the recessed ends of a concrete
block are called the SHELL (fig. 7-38). The
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