Minimum Roof Slope Ibc

When required testing is in accordance with astm e108 or ul 790.

Minimum roof slope ibc. Asphalt shingles require a minimum roof pitch of 2 12 or greater. The minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems. Minimum pitch for corrugated metal roof. 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.

This 1 4 12 minimum roof slope requirement also applies to spray polyurethane foam spf roof systems in new construction. 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. 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 lapped non soldered seam metal roofs without applied lap sealant shall be three units vertical in 12 units horizontal 25 percent 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. Let us recap on the minimum roof pitch required for each type of roofing material. Metal roof shingles require a minimum roof pitch of 3 12 or greater. For metal panel roof systems with nonsoldered seams with applied lap sealant ibc 2018 prescribes a 1 2 12 minimum roof slope.

The minimum slope for standing seam of roof systems shall be one quarter unit. Clay and concrete tile requires a minimum roof pitch of 2 1 2 12 or greater. Lap sealants shall be applied in accordance with the approved manufacturer s installation instructions. 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.

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. 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 roof fire resistance ratings apply based on the type of construction and some building types do not require a fire rating. 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.