What is the code required minimum pitch/slope for a metal roof?
Monday, September 16, 2019
The traditional metal roof types, such as 5V-crimp (shown above) and corrugated, are rated by the manufacturers for use down to a 3/12 pitch—three inches of vertical “rise” for every foot of horizontal “run.” Because of the shallow height of the undulating ridges of the 5V and corrugated profiles and the use of exposed metal fasteners to screw the metal to the roof deck, they are limited to a slope that will shed rain quickly.
But the taller profiles, like standing seam and PBR (shown below), can be installed on roofs with as low as 1/4” or 1/2” in 12” pitch. Their fasteners are either concealed or screwed at the top of a ridge, which makes them less likely to leak.
Here’s the citation from the 2017 Residential Edition of the Florida Building Code for minimum slope of metal roof panels, and the Internation Residential Code (IRC) is similar. But the manufacturers installation instructions and minimum slope always trump the code.
A great place to learn more about all the different metal roof profiles, color choices, what minimum slope each profile is rated for, and installation standards is the Gulf Coast Supply and Manufacturing website at www.gulfcoastsupply.com.
Also, see our blog post How do you flash skylight, chimney, and pipe vent roof penetrations on a metal roof?
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