Min Roof Slope For Asphalt Shingles

Asphalt felt paper that is tacked to the roof sheathing.

Min roof slope for asphalt shingles.

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. Asphalt shingles continue to be the most widely installed roof covering option in north america. Minimum required slope x in 12 minimum required slope degrees asphalt shingles. For example if it is a very low slope water including snowmelt or.

Therefore the asphalt manufactures base their warranties around the minimum recommended pitch of 4 in 12. Asphalt shingles can only be installed on roof slopes of 2 12 or greater. What precautions need to be taken to install shingles on low slopes. The 2 12 number is rise over run or two units of vertical for every 12 units horizontal.

This means for every 12 horizontal units the roof must rise a minimum of 2 vertical units. Why is 2 12 the minimum. Considering the roof slope requirement is important. The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles.

There are differing opinions as to the minimum slope for a roof but the generally accepted minimum is 3 12. The minimum requirement is 2 12. Minimum slope for asphalt shingles. What is the minimum pitch slope of an asphalt shingle roof.

18 43 asphalt shingles with special underlayment requirements 2 in 12. For those who don t understand the roof pitch number here is a way to envision it. This number corresponds to the number of inches of rise in a 12 foot run. In 12 0 25 in 12 1 19 built up roof coal tar pitch.

A roof slope of 2 12 up to but not including 4 12 is considered as low in residential construction. Asphalt composition shingles are designed to be installed on roof slopes greater than a 4 in 12 pitch. The minimum slope for an asphalt shingle roof is 2 12. 9 46 built up roof asphalt.

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. That works out to about nine degrees if that works better for you. Asphalt shingles minimum roof slope roof pitch r905 2 2. According to this code the minimum slope for asphalt shingles is 17 degrees or two vertical units to twelve units in the horizontal.

All asphalt shingle roofs with a pitch of 4 12 or more have an underlayment of 15 lb. Shingles of all types need to have a slope to function properly. What slope is considered low slope for shingles. The requirements for an asphalt shingles roof are contained in the international building code.

They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends. Minimum required roof slope for roofing materials.