RIGHT TRIANGLE and ROOF FRAMING EXAMPLES
Roof Framing Definitions
y
(Rise):
The vertical distance measured from the wall’s top plate to
the intersection of the pitch line and the center of the ridge.
Span:
The horizontal distance or full width between the outside
edges of the wall’s top plates.
x
(Run):
The horizontal distance between the outside edge of the
wall’s top plate and the center of the ridge; in most cases this is
equivalent to half of the span.
θ
(Pitch):
Pitch and Slope are synonymous in modern trade lan-
guage. Pitch/Slope of a roof is generally expressed in two types of
measurement:
1) Ratio of unit Rise to unit Run* — 7/12 or 7 Inch
2) Angle of rafters, in degrees — 30.26°
*Note:
The
unit
rise
is
the
number
of
Inches
of
Rise
per
Foot
(12
Inches)
of
unit
Run.
The
unit
Run
is
expressed
as
one
Foot
(12
Inches).
Plate:
The
top
horizontal
wall
member
that
the
ceiling
joist
and
rafters
sit
on
and
fasten
to.
Ridge:
The
uppermost
point
of
two
roof
planes.
This
rafter
is
the
uppermost
rafter
that
all
Hip,
Valley,
Valley
Jack,
and
Common
rafters
are
fastened
to.
84
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HEET
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ETAL
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