Minimum Roof Slope Angle

Roof slope equivalents as rise.

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. The minimum pitch for shingles is 1 6 which is equivalent to 4 inches rise to 24 inches run. 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. 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 following tableprovides the minimum required allowable roof slope for each type of roofing material mentioned in the code. The requirements for an asphalt shingles roof are contained in the international building code. 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.

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. Remember metal roofing is more expensive than shingles. The metal roof minimum slope doesn t stray far from other building with different material.

The standard of lower pitch actually ranges between 1 12 to 5 12. This means for every 12 horizontal units the roof must rise a minimum of one fourth vertical unit. The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles. You need to consider the slope requirements of each panel to determine this minimum slope.

Asphalt shingles continue to be the most widely installed roof covering option in north america. 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 minimum slope of a roof depends on the roof s profile. The minimum pitch for a standing seam metal roof is 1 4 or 3 inches rise to 12 inches run.

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.