These are also the most common pitches for shed roofs.
Minimum roof angle for shingles.
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.
The angle of a 2 12 pitch roof is roughly 9 46 degrees rounded to 9 5 in most cases.
Metal roof shingles can only be installed on roof slopes of 3 12 or greater 25 slope.
What is the minimum slope for an asphalt shingle roof.
Use a handy tool like snow load calculator to help you determine if your roof can handle the weight of snow based on its pitch.
Flat and nearly flat roofs a pitch of 1 in 12 or 2 in 12 cannot be covered with shingles or shakes of any material since there is not enough angle to combat the danger of blow off.
Asphalt shingles continue to be the most widely installed roof covering option in north america.
How roof pitch determines suitable roofing systems.
The minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems.
The highest degree possible is a 45 degree roof which is a 12 12 pitch roof.
The requirements for an asphalt shingles roof are contained in the international building code.
This means for every 12 horizontal units the roof must rise a minimum of 3 vertical units.
According to this code the minimum slope for asphalt shingles is 17 degrees or two vertical units to twelve units in the horizontal.
The standard for roof pitch is 4 12 though a 2 12 is completely fine for most structures.
The 2 12 number is rise over run or two units of vertical for every 12 units horizontal.
For simplicity sake every degree of pitch is roughly 4 75 degrees.
Installation on roof slopes below a 2 in 12 pitch is not recommended at all.
The minimum pitch for shingles is 1 6 which is equivalent to 4 inches rise to 24 inches run.
That works out to about nine degrees if that works better for you.
Again the most important consideration is the weather.
The minimum requirement is 2 12.
Determine the minimum slope of the roof based on the roofing material.
Shingles of all types need to have a slope to function properly.
The asphalt shingle manufactures recommend that you install asphalt shingles on a recommended minimum of 4 in 12 or greater however most manufactures will warrant their shingles down to a 2 in 12 pitch if the recommended installation method is used.
Any roof from 4 12 to 9 12 is considered an ordinary angle for a roof.
The following table provides the minimum required allowable roof slope for each type of roofing material mentioned in the code.
