Min Roof Slope For Asphalt Shingles

Asphalt felt paper that is tacked to the roof sheathing.

Min roof slope for asphalt shingles.

There are differing opinions as to the minimum slope for a roof but the generally accepted minimum is 3 12. In 12 0 25 in 12 1 19 built up roof coal tar pitch. Asphalt shingles minimum roof slope roof pitch r905 2 2. The 2 12 number is rise over run or two units of vertical for every 12 units horizontal.

The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles. Some people recommend not installing asphalt shingles on slopes below 5 12 but a skilled roofer may well be able to make this work. What slope is considered low slope for shingles. That works out to about nine degrees if that works better for you.

According to this code the minimum slope for asphalt shingles is 17 degrees or two vertical units to twelve units in the horizontal. 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. Asphalt shingles can only be installed on roof slopes of 2 12 or greater. Asphalt composition shingles are designed to be installed on roof slopes greater than a 4 in 12 pitch.

For example if it is a very low slope water including snowmelt or. What precautions need to be taken to install shingles on low slopes. A roof slope of 2 12 up to but not including 4 12 is considered as low in residential construction. This means for every 12 horizontal units the roof must rise a minimum of 2 vertical units.

What is the minimum pitch slope of an asphalt shingle roof. Asphalt shingles continue to be the most widely installed roof covering option in north america. Therefore the asphalt manufactures base their warranties around the minimum recommended pitch of 4 in 12. The requirements for an asphalt shingles roof are contained in the international building code.

Minimum slope for asphalt shingles. Why is 2 12 the minimum. Minimum required slope x in 12 minimum required slope degrees asphalt shingles. Roofing material or system.

Shingles of all types need to have a slope to function properly. This number corresponds to the number of inches of rise in a 12 foot run. 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. For those who don t understand the roof pitch number here is a way to envision it.

All asphalt shingle roofs with a pitch of 4 12 or more have an underlayment of 15 lb. Minimum required roof slope for roofing materials. 18 43 asphalt shingles with special underlayment requirements 2 in 12. They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends.

9 46 built up roof asphalt. For low slopes as well as any other slope your local building department should be contacted.