Figure 1-64.—Ribband installation.
in the same direction as the rafters, as shown in
with two 16d nails to the top of each ceiling joist, as
figure 1-62. The 2 by 4s should be nailed to the top of
shown in figure 1-65. The strongbacks are blocked up
each ceiling joist with two 16d nails. The 2 by 4 pieces
and supported over the outside walls and interior
should be spaced no more than 4 feet apart, and the ends
partitions. Each strongback holds a ceiling joist in line
secured to the heels of the rafters or to blocking over the
and also helps support the joist at the center of its span.
outside walls.
Roof Slope
When ceiling joists run in the same direction as the
roof rafters, the outside ends must be cut to the slope of
the roof. Ceiling frames are sometimes constructed with
stub joists (fig. 1-63). Stub joists are necessary when, in
certain sections of the roof, rafters and ceiling joists do
not run in the same direction. For example, a
low-pitched hip roof requires stub joists in the hip
section of the roof.
Ribbands and Strongbacks
Ceiling joists not supporting a floor above require
no header joists or blocking. Without the additional
header joists, however, ceiling joists may twist or bow
at the centers of their span. To help prevent this, nail a
1 by 4 piece called a ribband at the center of the spans
(fig. 1-64). The ribband is laid flat and fastened to the
top of each joist with two 8d nails. The end of each
ribband is secured to the outside walls of the building.
A more effective method of preventing twisting or
bowing of the ceiling joists is to use a strongback. A
strongback is made of 2 by 6 or 2 by 8 material nailed
to the side of a 2 by 4 piece. The 2 by 4 piece is fastened
Figure 1-65.—Strongback.
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