The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles.
Minimum slope for lean to roof.
The minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems.
With regards to metal roofing the profile refers to the shape adopted by the metal sheets when they are bent to form the panels.
The way pitch also known as roof slope is measured is rise over run.
Roof pitch is the measurement of roof steepness.
After that the miimum pitch for metal panels depending on the methods used to join the panels.
Express the slope of a metal roof by a ratio which indicates the pitch of the roof.
You need to consider the slope requirements of each panel to determine this minimum slope.
The minimum pitch for metal roof shingles and lapped non soldered panels is 3 12.
The minimum pitch for a roof is 1 4 12 which translates to 1 4 inch rise to 12 inches of run.
A ratio is the most common way of expressing roof pitch or roof slope but degrees are also possible.
The profile is the shape taken by the sheets when you bend them to form panels.
So if your roof rises 4 inches for every 12 inches of horizontal length then the pitch of your roof is expressed as 4 12.
Asphalt shingles typically have a minimum slope rating of 4 in 12.
This slope works well for sheds that are fairly narrow like 4 to 6 feet but for sheds that are 8 or wider the shed roof becomes unsightly high.
Minimum pitch for metal roof.
The minimum roof slope for metal roofs is dependent upon the roof profile.
However you can only use this pitch with built up roofing or specialized synthetic roofing.
Asphalt shingles continue to be the most widely installed roof covering option in north america.
The minimum slope of a roof depends on the roof s profile.
The minimum slope for standing seam of roof systems shall be one quarter unit vertical in 12 units horizontal 2 percent slope.
This means that for every 12 inches of horizontal distance across the shed the roof will rise 4 inches.
The profile refers to the shape the metal sheets take when they bend to.
They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends.
To get the minimum pitch for a metal roof the vertical rise per foot is divided by the horizontal slope.
The values given here.