Roof Pitch Formula. Pitched roofs, including gabled and hipped roofs, are the most common types in the United States. Use our Wisconsin Roof Snow Loads map to easily determine the roof design snow load (Wisconsin Administrative Code: SPS 321 SubChapter 2) for any location in the State of Wisconsin. Shingles of all types need to have a slope to function properly. So, you would need to pick the right option, as most regular standing seam metal roofs will require a roof pitch of 2:12 or even 3:12 at a minimum. The short, simple answer is 2:12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles. I don't know what you mean by "the optimum roof pitch in Vermont for shedding snow with a metal roof." The slope of the roof is measured by the vertical rise of the roof to the horizontal run and is expressed as a fraction. One key difference in industry’s approach to snow on roofs is that keeping snow on the roof is something that they desire-quite the opposite from the trend in North America. Moreover, Low Slope Metal Roofs are not prone to the degradation experienced by organic materials, enabling these roofs to better resist the elements. Manufacturers therefore recommend a ‘minimum pitch’ to install their product so that rainwater and debris runs off the glass more effectively, keeping the skylight cleaner for longer. If this isn't practical then perform the same measurement on the underside of the roof. Wisconsin has not adopted the International Residential Code (IRC) and utilizes its own Uniform Dwelling Code (UDC) for all residential structures. But since there is still a wide variety of slate roofing systems, there are occasions when the minimum pitch can go down to as low as 15 0 depending on the uniqueness of the roof. Asphalt shingles continue to be the most widely installed roof covering option in North America. See the below Florida Building Code Fifth Edition (2014, 2017) sections below to determine which slope is appropriate based on your specific design scenario. What is the Minimum Slope for an Asphalt Shingle Roof. Minimum metal roof slope depends on the roof profile, building design, climate and site location. What is the minimum Pitch/Slope of an Asphalt Shingle Roof? The recommended pitch for skylight installation on a flat roof. If you don't like the looks of a 12/12 roof, and you don't like to work on a steep roof, you are free to build a roof with any pitch you want. Each roof cladding section specifies: a minimum acceptable roof slope for the given profile (see Table 1) roofing material manufacturing and other standards flashing and junction details including minimum flashing covers and upstands roof penetration details (note that roof penetrations equal to or below 10° require specific design). There are some standing seam metal roofing options available from Atas and other manufacturers that can be installed on a roof with pitch of 1:12. Low-slope roofs are not totally flat, their roof slope generally ranges from 1/4:12 to 3:12.