The 2 12 number is rise over run or two units of vertical for every 12 units horizontal.
Minimum roof pitch for asphalt shingles.
What precautions need to be taken to install shingles on low slopes.
According to this code the minimum slope for asphalt shingles is 17 degrees or two vertical units to twelve units in the horizontal.
The minimum requirement is 2 12.
Asphalt shingles do require that you have a minimum pitch to your roof.
Let us recap on the minimum roof pitch required for each type of roofing material.
What slope is considered low slope for shingles.
The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles.
Asphalt felt paper that is tacked to the roof sheathing.
Considering the roof slope requirement is important.
Asphalt shingles require a minimum roof pitch of 2 12 or greater.
There are plenty of other options however for flat and nearly.
They won t be appropriate for all roofs.
Therefore the asphalt manufactures base their warranties around the minimum recommended pitch of 4 in 12.
Fortunately the requirements are quite accommodating.
The following table provides the minimum required allowable roof slope for each type of roofing material mentioned in the code.
The minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems.
What is the minimum pitch slope of an asphalt shingle roof.
Metal roof shingles require a minimum roof pitch of 3 12 or greater.
For example if it is a very low slope water including snowmelt or.
Minimum slope for asphalt shingles.
Clay and concrete tile requires a minimum roof pitch of 2 1 2 12 or greater.
But shingle roofing is not watertight in the sense that standing water or wind driven water on a low slope roof can work its way up between the laps which is the reason for the minimum 2 12 slope.
All asphalt shingle roofs with a pitch of 4 12 or more have an underlayment of 15 lb.
They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends.
Shingles of all types need to have a slope to function properly.
That works out to about nine degrees if that works better for you.
For low slopes as well as any other slope your local building department should be contacted.
Asphalt composition shingles are designed to be installed on roof slopes greater than a 4 in 12 pitch.
For those who don t understand the roof pitch number here is a way to envision it.
If you re having asphalt shingles put on your roof you will have to have a minimum slope.
The minimum slope for an asphalt shingle roof is 2 12.
A roof slope of 2 12 up to but not including 4 12 is considered as low in residential construction.
The requirements for an asphalt shingles roof are contained in the international building code.