Ibc Minimum Roof Slope

For roof slopes from two units vertical in 12 units horizontal 17 percent slope and up to four units vertical in 12 units horizontal 33 percent slope underlayment shall be two layers applied in the following manner.

Ibc minimum roof slope.

Minimum roof fire resistance ratings apply based on the type of construction and some building types do not require a fire rating. The following table provides the minimum required allowable roof slope for each type of roofing material mentioned in the code. Asphalt shingles continue to be the most widely installed roof covering option in north america. For metal panel roof systems with nonsoldered seams with applied lap sealant ibc 2018 prescribes a 1 2 12 minimum roof slope.

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. The minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems. The ibc table 1505 1 lists the minimum requirements for roof covering fire resistance classifications a b or c for all types of. According to the 2012 international building code 1507 4 2 deck slope minimum slopes for roof panels need to comply with the following.

When required testing is in accordance with astm e108 or ul 790. Asphalt shingles require a minimum roof pitch of 2 12 or greater. Reroofing shall not be required to meet the minimum design slope requirement of one quarter unit vertical in 12 units horizontal 2 percent slope in section 1507 of the international building code for roofs that provide positive roof drainage. Minimum pitch for corrugated metal roof.

They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends. This 1 4 12 minimum roof slope requirement also applies to spray polyurethane foam spf roof systems in new construction. For standing seam metal roof panel systems a 1 4 12 minimum roof slope is prescribed. Let us recap on the minimum roof pitch required for each type of roofing material.

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. Clay and concrete tile requires a minimum roof pitch of 2 1 2 12 or greater. The minimum slope for lapped non soldered seam metal roofs without applied lap sealant shall be three units vertical in 12 units horizontal 25 percent slope. The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles.

Apply a minimum 19 inch wide 483 mm strip of underlayment felt parallel with and starting at the eaves fastened sufficiently to hold in place.