A flat roof is more likely to allow rain to pool and this can cause damage especially if the roof is made of a porous substance like wood.
Minimum shed roof angle.
The roof comprises a simple beam.
Fix your roof deck and you are done.
The requirements for an asphalt shingles roof are contained in the international building code.
Again the most important consideration is the weather.
The 2 12 number is rise over run or two units of vertical for every 12 units horizontal.
The minimum requirement is 2 12.
Any roof from 4 12 to 9 12 is considered an ordinary angle for a roof.
Much depends on what your intended use for the shed actually is.
However you can only use this pitch with built up roofing or specialized synthetic roofing.
If you are only trying to keep a wood pile dry or storing a few outdoor tools and light machinery out of the weather then you might consider a simple single pitch roof since most everything inside will be stored at ground level and pulled out from the outside of the shed.
Well there are a few more steps to add the roof covering and trim but you can read about them below potential roof framing for a flat roofed shed.
The minimum pitch for a roof is 1 4 12 which translates to 1 4 inch rise to 12 inches of run.
This translates into a fall of just under 2 5 on an 8 foot roof.
I always recommend at least a minimum pitch of 1 in 40.
A pitch of 10 degrees or less is typically regarded as a flat roof.
According to this code the minimum slope for asphalt shingles is 17 degrees or two vertical units to twelve units in the horizontal.
A shingle roof like this north dallas garage in the photo above may have a failure no matter how good a job the installer did.