Minimum Roof Slope Ibc

Let us recap on the minimum roof pitch required for each type of roofing material.

Minimum roof slope ibc.

The minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems. Minimum roof fire resistance ratings apply based on the type of construction and some building types do not require a fire rating. 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. 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.

Just like other metal roofs the minimum pitch for a corrugated metal roof largely depends on the profile of the roof. For standing seam metal roof panel systems a 1 4 12 minimum roof slope is prescribed. 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. According to the 2012 international building code 1507 4 2 deck slope minimum slopes for roof panels need to comply with the following.

The minimum slope for standing seam of roof systems shall be one quarter unit. Lap sealants shall be applied in accordance with the approved manufacturer s installation instructions. 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. 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.

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. When required testing is in accordance with astm e108 or ul 790. 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. For metal panel roof systems with nonsoldered seams with applied lap sealant ibc 2018 prescribes a 1 2 12 minimum roof slope.

Clay and concrete tile requires a minimum roof pitch of 2 1 2 12 or greater. The ibc table 1505 1 lists the minimum requirements for roof covering fire resistance classifications a b or c for all types of. Asphalt shingles require a minimum roof pitch of 2 12 or greater. Minimum pitch for corrugated metal roof.

This 1 4 12 minimum roof slope requirement also applies to spray polyurethane foam spf roof systems in new construction.