Sample
Copyright © 2007 by Calculated Industries, Inc.
and Thomson Delmar Learning
Construction Master® Pro Workbook and Study Guide
Placed atop framed walls, rafters support the roof of a structure. There are
many types of roof styles, such as
gable, gambrel, shed, Mansard,
and
hip,
and several types of rafters, including those to be discussed here:
common,
hip, valley,
and
jack
rafters.
Common rafters connect the top
plate
of a wall with the
ridge,
and are
perpendicular to the ridge. Like the grade of a land area (see Chapter 2), the
incline of such rafters may be specified several different ways using the quan-
tities shown in
Figure 6-1.
The
slope
of a rafter (also called the
pitch ratio
) is
a decimal value that results from dividing the rise by the run, keeping both di-
mensions in feet or both dimensions in inches.
Pitch
of a rafter is the rise, in
inches, divided by the run, in feet, and is usually stated simply in inches. Pitch
may also be expressed as angle A in the figure, that angle between the rafter
and a horizontal line, and is given in degrees.
59
CHAPTER 6
Rafters
Warning
Material Adjustments:
The rafter length
calculations are the
point-to-point
measurements and do
not account for material
thickness.
Rafter Length (DIAG)
A
Run
Rise
Figure 6-1
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