## Saturday, February 9, 2013

### Pitch Break Shed Roof Rafter Calculator

This Pitch Break Shed Roof calculator will return roof framing trigonometry & geometry details for:

1.  Pitch Break Shed Roof Rafter Length
2. Pitch Break Shed Roof Miter Angle (Rake Cut Angle)
3. Total Pitch Break Run ( Intersection of Shed Roof and Main Roof)
4. Main Roof Intercept Length
5. Main Roof Run To Intersection of Main Roof And Shed Roof

```Using the Law of Sines
c = ( a × sin( C ) ) ÷ sin( A)

c = Shed Roof Rafter Length
C1 = 90° - Shed Roof Pitch Angle
C2 = 90° - (Main Roof Pitch Angle - Shed Roof Pitch Angle)
C = 90° - Shed Roof Pitch Angle + (90° - (Main Roof Pitch Angle - Shed Roof Pitch Angle))
C = C1 + C2
A = Main Roof Pitch Angle - Shed Roof Pitch Angle
a = Shed Roof Run

Shed Roof Rafter Length = (Shed Roof Run × sin(90° - Shed Roof Pitch Angle + (90° - (Main Roof Pitch Angle - Shed Roof Pitch Angle)))) ÷ sin(Main Roof Pitch Angle - Shed Roof Pitch Angle )
or
Shed Roof Rafter Length = (Shed Roof Run × sin(C)) ÷ sin(A)
or

Shed Altitude = sin(Shed Roof Pitch Angle) ×  Shed Run
Shed Altitude Run = Shed Altitude ÷ tan(Shed Roof Pitch Angle)
Shed Miter Cut Angle =  Main Roof Pitch Angle - Shed Roof  Pitch Angle
Main Altitude Run = Shed Altitude ÷ tan(Shed Miter Cut Angle)
Shed Rafter Length = Shed Altitude Run + Main Altitude Run
Main Intercept Run = (Shed Rafter Length  × cos( Shed Roof Pitch Angle)) - Shed Roof Run```