The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles.
Shingle roof slope.
What is the minimum slope for an asphalt shingle roof.
They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends.
The roof shingle calculator is a free estimator that serves a useful purpose during any roof repair or replacement project.
Metal roof shingles can only be installed on roof slopes of 3 12 or greater 25 slope.
This means for every 12 horizontal units the roof must rise a minimum of 3 vertical units.
The roof pitch between 2 12 and 4 12 is considered as a low pitch roof so shingles can be installed in the roof slope between 2 12 and 4 12.
Why is 2 12 the minimum.
Asphalt shingles continue to be the most widely installed roof covering option in north america.
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.
Shingles of all types need to have a slope to function properly.
For example if it is a very low slope water including snowmelt or rainwater drains slowly and this increases the chances of.
That works out to about nine degrees if that works better for you.
The minimum requirement is 2 12.