Minimum Roof Slope Angle

The standard of lower pitch actually ranges between 1 12 to 5 12.

Minimum roof slope angle.

According to this code the minimum slope for asphalt shingles is 17 degrees or two vertical units to twelve units in the horizontal. A quarter inch slope is the lowest you would go with a metal roof experts recommend at least a half inch minimum to ensure a weatherproof interior for your shed. 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. Asphalt shingles continue to be the most widely installed roof covering option in north america.

The following tableprovides the minimum required allowable roof slope for each type of roofing material mentioned in the code. Remember metal roofing is more expensive than shingles. Lap sealants shall be applied in accordance with the approved manufacturer s installation instructions. The minimum pitch for a standing seam metal roof is 1 4 or 3 inches rise to 12 inches run.

The minimum slope of a roof depends on the roof s profile. The minimum pitch is typically 3 12 meaning the roof should rise 3 inches for every 12 inches of horizontal foot. 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 metal roof minimum slope doesn t stray far from other building with different material.

The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles. This is the basis for calculating the angle which is approximately a 1 19 degree slope. This means for every 12 horizontal units the roof must rise a minimum of one fourth vertical unit. The minimum slope for lapped non soldered seam metal roofs with applied lap sealant shall be one half unit vertical in 12 units horizontal 4 percent slope.

The minimum slope for standing seam of roof systems shall be one quarter unit vertical in 12 units horizontal 2 percent slope. Express the slope of a metal roof by a ratio which indicates the pitch of the roof. The minimum pitch for shingles is 1 6 which is equivalent to 4 inches rise to 24 inches run. The requirements for an asphalt shingles roof are contained in the international building code.

Roof slope equivalents as rise.