Min Roof Slope For Shingles

The rise over run ratio is called the roof slope.

Min roof slope for shingles.

In case a slope greater than this is necessary then a double underlayment application must be used as per the requirements of the international building code. Tuesday september 11 2018 manufacturers of asphalt shingles recommend a pitch of 4 12 or more but the absolute minimum pitch is 2 12. In 12 0 25 in 12 1 19 built up roof coal tar pitch. That works out to about nine degrees if that works better for you.

This number corresponds to the number of inches of rise in a 12 foot run. They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends. This means for every 12 horizontal units the roof must rise a minimum of 2 vertical units. Also if asphalt shingles are installed on a roof slope of 2 12 to 4 12 it shall be provided with a double underlayment application.

Shingles of all types need to have a slope to function properly. Asphalt shingles can only be installed on roof slopes of 2 12 or greater. Some people recommend not installing asphalt shingles on slopes below 5 12 but a skilled roofer may well be able to make this work. The 2 12 number is rise over run or two units of vertical for every 12 units horizontal.

Nrca s recommended minimum roof slope guidelines for steep slope roof systems generally are greater at steeper inclines than those in the building code. The minimum requirement is 2 12. Asphalt shingles continue to be the most widely installed roof covering option in north america. You can measure the roof slope either using tape or smartphone applications.

Roofing material or system. 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. What is the minimum slope for an asphalt shingle roof.

If a roof slope rise is 4 inches when measured 12 inches along the bottom of the horizontal run the roof slope is said to be 4 12. What is the minimum pitch slope of an asphalt shingle roof. Pitch is measured in inches of vertical rise of the roof over one foot 12 inches of horizontal run. 18 43 asphalt shingles with special underlayment requirements 2 in 12.

9 46 built up roof asphalt. According to this code the minimum slope for asphalt shingles is 17 degrees or two vertical units to twelve units in the horizontal. Minimum pitch for corrugated metal roof. Minimum required roof slope for roofing materials.