The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles.
Minimum slope for wood shingle roof.
There are differing opinions as to the minimum slope for a roof but the generally accepted minimum is 3 12.
The following table provides the minimum required allowable roof slope for each type of roofing material mentioned in the code.
If 4 12 and above is normal and 2 12 is minimum what about properties with roofs in between the two such as a 3 12 pitched roof.
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.
They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends.
The function of the roof in weather and the environment determines the minimum pitch for a roof.
Normal roof slope for typical installation.
For example a shingle roof in a snowy region could be 2 12 but it is better to have a steeper.
Shingle exposures for wood roofs.
The minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems.
This means for every 12 horizontal units the roof must rise a minimum of 3 vertical units.
Why is 2 12 the minimum.
Low sloped roof shingle installation.
For asphalt shingle clay and concrete tile metal shingle slate and wood shake and shingle roof systems nrca recommends slopes of 4 12 or more.
Underlayment materials required to comply with astm d226 d1970 d4869 and d6757 shall bear a label indicating compliance to the standard.
The minimum slope for an asphalt shingle roof is 2 12.
Some people recommend not installing asphalt shingles on slopes below 5 12 but a skilled roofer may well be able to make this work.
Asphalt shingles continue to be the most widely installed roof covering option in north america.
Underlayment for asphalt shingles clay and concrete tile metal roof shingles mineral surfaced roll roofing slate and slate type shingles wood shingles wood shakes and metal roof panels shall conform to the applicable standards listed in this chapter.
For example if it is a very low slope water including snowmelt or.
This number corresponds to the number of inches of rise in a 12 foot run.
Considering the roof slope requirement is important.
Built up roofs minimum roof slope roof pitch r905 9 1.
Allowable shingle exposure may also vary by the shingle grade something that you might infer by visual inspection of the shingles matching against wood shingle grade definitions or.
Wood shakes minimum roof slope roof pitch r905 8 2.
The maximum weather exposure for wood shakes or wood shingles depends on the shingle size and the slope or pitch of the roof.