Roof Pitch Angle and Slope Factor Charts

 

Roof Pitch Symbols

 

Roof Pitch is a term describing how steep or flat your roof slope is.  The combination of two numbers are used to display or show the roof pitch.  Two most common methods (4/12 or 4:12) are used for marking the pitch of a roof.  On blue prints architects & engineers usually display the pitch of a roof in the format shown on right image where number (4) represents a rise and number (12) represents a length.  This means if a roof rises 4' in the length of 12', your Roof Pitch would be 4/12 or 18.43 degrees.

 

 

 

 

Roof Pitch and Corresponding Angles

 

Roof Pitch (slope)

Roof Angle (degree)

1:12 Pitch

4.76°

2:12 Pitch

9.46°

3:12 Pitch

14.04°

4:12 Pitch

18.43°

5:12 Pitch

22.62°

6:12 Pitch

26.57°

7:12 Pitch

30.26°

8:12 Pitch

33.69°

9:12 Pitch

36.87°

10:12 Pitch

39.81°

11:12 Pitch

42.51°

12:12 Pitch

45.00°

13:12 Pitch

47.29°

14:12 Pitch

49.40°

15:12 Pitch

51.34°

16:12 Pitch

53.13°

 

 

Slope Factor Chart 1:12 pitch - 6:12 pitch

 

Pitch of Roof

1:12

2:12

3:12

4:12

5:12

6:12

Slope Factor

1.0035

1.0138

1.0308

1.0541

1.0833

1.1180

Valley & Hip Factor

1.4167

1.4240

1.4362

1.4530

1.4743

1.5000

 

Slope Factor Chart 7:12 pitch - 12:12 pitch

 

Pitch of Roof

7:12

8:12

9:12

10:12

11:12

12:12

Slope Factor

1.1577

1.2019

1.2500

1.3017

1.3566

1.4142

Valley & Hip Factor

1.5298

1.5635

1.6008

1.6415

1.6853

1.7320

 

 

 

(A) x (Hip or Valley Factor) = (B)                            (A) x (Slope Factor) = (B)

Slope Factor Chart

 

 

 

 

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