However you can only use this pitch with built up roofing or specialized synthetic roofing.
Minimum roof pitch for dormers.
A 4 12 pitch is around 18 5 degrees but not exactly.
Having a steeper pitched roof allows for more space in a shed loft.
Roofing gutters and all waterproofing anywhere minimum roof pitch i am planning a shed dormer with a roof that will have about 3 12 pitch.
The minimum pitch for a roof is 1 4 12 which translates to 1 4 inch rise to 12 inches of run.
However rise over run is more efficient and easier to understand for the average diyer.
The loft space would be much larger with a roof pitch of 45 degrees.
Thus a 4 12 pitch would be a 33 slope.
You can also divide the rise over run multiply by 100 and get a percentage.
A shed dormer on the other hand is usually had on homes with a roof pitch of at least 8 in 12 or steeper.