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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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To learn more about roofs and attics, see these other blog posts:
• Why is my roof sheathing sagging between the trusses?
• Why is granule loss a problem for an asphalt shingle roof?
• What are the mistakes to avoid when doing attic improvements?
• What causes roof shingles to curl up at corners?
• What causes shingles to buckle along a line on the roof?
• What is "ponding" on a flat roof?
• Is an attic required to have a light by the building code?
• How can I inspect my roof for hurricane damage?
• Why is premature curl of roof shingles a problem?
• How can I tell if a roof has more than one layer of shingles?
• What are the common problems with attic insulation?
• What is the life expectancy of an asbestos cement shingle roof?
• What's the average lifespan of a roof?
• Why is it a mistake to replace a roof and not replace its flashings?
• Why is there no attic access hatch in the house?
• What is the building code requirement for an attic access hatch, scuttle, or door?
• How can I be sure my roofing contractor got a permit?
• How many layers of roofing are allowed on a home?
• What are the dark lines running parallel to shingles on my roof?
• How can I make my roof last longer?
• What are the warning signs of a dangerous attic pull-down ladder?
• How can I find out the age of a roof?
• Should I buy a house that needs a new roof?
• Should I buy a house with an old roof?
• What are those metal boxes on the roof?
• What does "lack of tab adhesion" in an asphalt shingle roof mean?
• Why do roof edges start leaking?
• Why do my dormer windows leak?
• Do home inspectors go on the roof? Do they get in the attic?
• Why does my homeowner's insurance want a roof inspection?
• What are the hazards to avoid when going into an attic?
Visit our METAL ROOFS and ROOF AND ATTIC pages for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.
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