The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles.
Shingle roof slope.
The following table provides the minimum required allowable roof slope for each type of roofing material mentioned in the code.
They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends.
Why is 2 12 the minimum.
The roof shingle calculator is a free estimator that serves a useful purpose during any roof repair or replacement project.
The minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems.
That works out to about nine degrees if that works better for you.
What is the minimum slope for an asphalt shingle roof.
The 2 12 number is rise over run or two units of vertical for every 12 units horizontal.
Asphalt shingles continue to be the most widely installed roof covering option in north america.
Shingles of all types need to have a slope to function properly.
This means for every 12 horizontal units the roof must rise a minimum of 3 vertical units.
For example if it is a very low slope water including snowmelt or rainwater drains slowly and this increases the chances of.
Considering the roof slope requirement is important.
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.