Minimum Roof Slope Angle

Lap sealants shall be applied in accordance with the approved manufacturer s installation instructions.

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. 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 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.

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. Roof slope equivalents as rise. 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 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. This means for every 12 horizontal units the roof must rise a minimum of one fourth vertical unit. The minimum pitch is typically 3 12 meaning the roof should rise 3 inches for every 12 inches of horizontal foot. This is the basis for calculating the angle which is approximately a 1 19 degree slope.

The minimum pitch for shingles is 1 6 which is equivalent to 4 inches rise to 24 inches run. The standard of lower pitch actually ranges between 1 12 to 5 12. Express the slope of a metal roof by a ratio which indicates the pitch of the roof. The metal roof minimum slope doesn t stray far from other building with different material.

According to this code the minimum slope for asphalt shingles is 17 degrees or two vertical units to twelve units in the horizontal. Remember metal roofing is more expensive than shingles. You need to consider the slope requirements of each panel to determine this minimum slope. The profile is the shape taken by the sheets when you bend them to form panels.

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.