Any roof from 4 12 to 9 12 is considered an ordinary angle for a roof.
Minimum roof angle for shingles.
That works out to about nine degrees if that works better for you.
What is the minimum slope for an asphalt shingle roof.
The angle of a 2 12 pitch roof is roughly 9 46 degrees rounded to 9 5 in most cases.
The 2 12 number is rise over run or two units of vertical for every 12 units horizontal.
The minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems.
This means for every 12 horizontal units the roof must rise a minimum of 3 vertical units.
Mineral surfaced roll roofing minimum roof slope roof pitch r905 5 2.
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.
The requirements for an asphalt shingles roof are contained in the international building code.
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.
Determine the minimum slope of the roof based on the roofing material.
For simplicity sake every degree of pitch is roughly 4 75 degrees.
How roof pitch determines suitable roofing systems.
Asphalt shingles continue to be the most widely installed roof covering option in north america.
The minimum pitch for shingles is 1 6 which is equivalent to 4 inches rise to 24 inches run.
The highest degree possible is a 45 degree roof which is a 12 12 pitch roof.
Metal roof shingles can only be installed on roof slopes of 3 12 or greater 25 slope.
The minimum requirement is 2 12.
The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles.
Installation on roof slopes below a 2 in 12 pitch is not recommended at all.
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.
The following table provides the minimum required allowable roof slope for each type of roofing material mentioned in the code.
Again the most important consideration is the weather.
Shingles of all types need to have a slope to function properly.
Metal roof shingles minimum roof slope roof pitch r905 4 2.
