Irc 2009 Minimum Roof Pitch

What is the minimum slope for an asphalt shingle roof.

Irc 2009 minimum roof pitch.

Asphalt shingles continue to be the most widely installed roof covering option in north america. Jurisdictions in the us do not commonly require fire resistance classifications for roof coverings on one and two family residential dwellings. The 2009 irc has something to say about roof materials and their slopes. The international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process.

The international residential code 2018 edition irc 2018 prescribes minimum roof slopes similar to those of ibc 2018 except irc 2018 indicates a 3 12 minimum roof slope for wood shakes. Minimum roof slope roof pitch r905 15 1 liquid applied roofing must have a design roof slope of 1 4 12 or greater 2 slope. The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles. The irc section r902 1 requires class a b or c fire resistant roofing only in jurisdictions designated by law or where the edge of the roof is less than 3 feet from the property line.

As a very general rule a steeper roof will perform better and last longer than a roof with a lower slope. In cases of roof system replacement and re cover of existing low slope roof systems ibc 2018 and irc 2018 waive the codes 1 4 12 minimum slope. The minimum slope for standing seam of roof systems shall be one quarter unit vertical in 12 units horizontal 2 percent slope. It brings together all building plumbing mechanical fuel gas energy and electrical provisions for one and two family residences.

A good rule of thumb is that a roof slope of 5 12 doesn t have any additional requirements. The minimum slope for lapped nonsoldered seam metal roofs with applied lap sealant shall be one half unit vertical in 12 units horizontal 4 percent slope. Built up roofs shall have a design slope of a minimum of one fourth unit vertical in 12 units horizontal 2 percent slope for drainage except for coal tar built up roofs which shall have a design slope of a minimum one eighth unit vertical in 12 units horizontal 1 percent slope. They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends.

For the actual language in the model 2018 international residential code this link will take you to section r905 requirements for roof coverings. Lap sealants shall be applied in accordance with the approved manufacturer s installation instructions. January 2009 code for residential buildings that creates minimum regulations for one and two family dwellings of three stories or less.