Irc 2009 Minimum Roof Pitch

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.

Irc 2009 minimum roof pitch.

Asphalt shingles continue to be the most widely installed roof covering option in north america. 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 2009 irc has something to say about roof materials and their slopes. January 2009 code for residential buildings that creates minimum regulations for one and two family dwellings of three stories or less.

It brings together all building plumbing mechanical fuel gas energy and electrical provisions for one and two family residences. For the actual language in the model 2018 international residential code this link will take you to section r905 requirements for roof coverings. Get to 4 12 or below on some materials and the cost of the roof can go up due to additional underlayment requirements. The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles.

This means for every 12 horizontal units the roof must rise a minimum of one fourth vertical unit. 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. 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.

A good rule of thumb is that a roof slope of 5 12 doesn t have any additional requirements. Jurisdictions in the us do not commonly require fire resistance classifications for roof coverings on one and two family residential dwellings. What is the minimum slope for an asphalt shingle roof. The minimum slope for standing seam of roof systems shall be one quarter unit vertical in 12 units horizontal 2 percent slope.

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. The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures. They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends.