Instructions / Assembly

SM-Rib
34
Helpful Formulas
Roof Slope Conversion Table with Roof Pitch Multiplier
Rise
and Run
Multiply
Flat Area
by
LF of Hips or
Valleys per LF of
Common Run
Decimal
Fraction
of a Foot
Inch Fraction
2 in 12 1.041 1.424 1” .083
3 in 12 1.031 1.436 2” .167
4 in 12 1.054 1.453 3” .250
5 in 12 1.083 1.474 4” .333
6 in 12 1.118 1.500 5” .417
7 in 12 1.158 1.530 6” .500
8 in 12 1.202 1.564 7” .583
9 in 12 1.250 1.600 8” .667
10 in 12 1.302 1.641 9” .750
11 in 12 1.357 1.685 10” .833
12 in 12 1.413 1.732 11” .917
12” 1.00
Triangle
Area = 1/2 x B x H
Volume = 1/2 x B x H x W
A = C
2
- B
2
= H
B = C
2
- A
2
= Run
C = A
2
+ B
2
= Slope
C
A
B
Roof Calculator
Height = 1/2 Span x Rise/Run (common run)
Height = Span x Pitch
Slope = Common Run x Factor
Rise
Slope
Span
Run
90°
80°
70°
60°
50°
40°
30°
20°
10°
45 Degrees
42.50 Degrees
39.75 Degrees
36.75 Degrees
33.75 Degrees
30.25 Degrees
26.50 Degrees
22.75 Degrees
18.50 Degrees
14.90 Degrees
9.50 Degrees
4.75 Degrees
0.0 Degrees
12/12
11/12
10/12
9/12
8/12
7/12
6/12
5/12
4/12
3/12
2/12
1/12
Flat
Angle
Rise
Run