Minimum Roof Pitch For Flat Roof

The minimum slope for standing seam of roof systems shall be one quarter unit vertical in 12 units horizontal 2 percent slope.

Minimum roof pitch for flat roof.

The minimum roof slope for metal roofs is dependent upon the roof profile. For example a roof that rises 3 inches for every 12 inches has a pitch of 3 12. The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles. The minimum pitch for a roof is 1 4 12 which translates to 1 4 inch rise to 12 inches of run.

The profile refers to the shape the metal sheets take when they bend to. Low slope roofs are not totally flat their roof slope generally ranges from 1 4 12 to 3 12. A low pitched roof is easier to put up and maintain but may show very little of its material at ground level. However you can only use this pitch with built up roofing or specialized synthetic roofing.

According to the international building code the typical built up flat roof that uses tar or asphalt goes by the guideline that for every foot 12 inches of a flat roof a minimum of inch must step up or down. Depending on the roof profile there are minimum roof slope requirements for each panel which need to be considered. Slate and slate type shingles require a minimum roof pitch of 4 12 or greater. This is the basis for calculating the angle which is approximately a 1 19 degree slope.

In order to achieve this drop a slightly steeper angle of 1 40 1 44 should be the aim when installing a flat roof as this accounts for surface. Wood shingles require a minimum roof pitch of 3 12 or greater. To get the minimum pitch for a metal roof the vertical rise per foot is divided by the horizontal slope. Asphalt shingles continue to be the most widely installed roof covering option in north america.

Minimum pitch for metal roof. They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends. The minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems. Built up roofs require a minimum roof pitch of 1 4 12 or greater.

Minimum metal roof slope depends on the roof profile building design climate and site location. Mineral surfaced roll roofing requires a minimum roof pitch of 1 12 or greater. Normally 1 80 0 72 is the recommended minimum angle for a slope and this is universal across the vast majority of flat roofing systems regardless of the materials that they incorporate. The following table provides the minimum required allowable roof slope for each type of roofing material mentioned in the code.

To calculate roof pitch take the lowest point of the roof and measure the amount of rise for every 12 inches of horizontal movement toward the highest point.