Asphalt shingles continue to be the most widely installed roof covering option in north america.
Minimum roof angle for shingles.
According to this code the minimum slope for asphalt shingles is 17 degrees or two vertical units to twelve units in the horizontal.
Metal roof shingles minimum roof slope roof pitch r905 4 2.
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.
The following table provides the minimum required allowable roof slope for each type of roofing material mentioned in the code.
This means for every 12 horizontal units the roof must rise a minimum of 3 vertical units.
The 2 12 number is rise over run or two units of vertical for every 12 units horizontal.
How roof pitch determines suitable roofing systems.
That works out to about nine degrees if that works better for you.
Mineral surfaced roll roofing minimum roof slope roof pitch r905 5 2.
For simplicity sake every degree of pitch is roughly 4 75 degrees.
The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles.
Any roof from 4 12 to 9 12 is considered an ordinary angle for a 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.
What is the minimum slope for an asphalt shingle roof.
The minimum requirement is 2 12.
The requirements for an asphalt shingles roof are contained in the international building code.
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.
Metal roof shingles can only be installed on roof slopes of 3 12 or greater 25 slope.
The minimum pitch for shingles is 1 6 which is equivalent to 4 inches rise to 24 inches run.
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.
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.
Shingles of all types need to have a slope to function properly.
Installation on roof slopes below a 2 in 12 pitch is not recommended at all.
The minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems.
These are also the most common pitches for shed roofs.
