Minimum Roof Slope Angle

You need to consider the slope requirements of each panel to determine this minimum slope.

Minimum roof slope angle.

The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles. The following tableprovides the minimum required allowable roof slope for each type of roofing material mentioned in the code. The profile is the shape taken by the sheets when you bend them to form panels. The minimum slope for standing seam of roof systems shall be one quarter unit vertical in 12 units horizontal 2 percent slope.

The minimum pitch is typically 3 12 meaning the roof should rise 3 inches for every 12 inches of horizontal foot. This means for every 12 horizontal units the roof must rise a minimum of one fourth vertical unit. This is the basis for calculating the angle which is approximately a 1 19 degree slope. Run in degrees and as percentage the minimum roof slope allowed by code for any type of roofis in 12 applicable only to coal tar pitch roof systems.

Remember metal roofing is more expensive than shingles. The requirements for an asphalt shingles roof are contained in the international building code. Asphalt shingles continue to be the most widely installed roof covering option in north america. Lap sealants shall be applied in accordance with the approved manufacturer s installation instructions.

The standard of lower pitch actually ranges between 1 12 to 5 12. 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. Express the slope of a metal roof by a ratio which indicates the pitch of the roof. According to this code the minimum slope for asphalt shingles is 17 degrees or two vertical units to twelve units in the horizontal.

The metal roof minimum slope doesn t stray far from other building with different material. The minimum slope of a roof depends on the roof s profile. 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. 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 pitch for a standing seam metal roof is 1 4 or 3 inches rise to 12 inches run.