Metal Roof Directly On Felt And Sheathing

Hi todd i have a pole barn design structure that had been turned into a livable dwelling with cathedral ceilings using rigid foam between the metal roof and the ceiling sheetrock i am redoing this and putting a decking down with tyvek protec 200 and then reattaching the metal roof and adding circular pest resistant soffit vents at the end rafters of the roof between purlins for ventilation.

Metal roof directly on felt and sheathing.

The 2006 irc that minnesota uses says that metal roofing can be installed with solid or spaced sheathing per the manufacturer. The asphalt in the felt paper is waterproof and does a great job of protecting the untreated wood roof sheathing. Felt and ice and water is 415 so that totals 4608. Metal roofing is about 135 sq so that makes it around 4700 plus a few hundred for the purlins.

Overlap the edge of the roof by 1 inch. Their attempt to save money may cost them more in the long run. Make sure there s a 1 inch overlap the edge of the roof by one inch then secure it by drilling 1 and 1 2 inch galvanized metal screws through the panel in 12 inch to 16 inch intervals. Secure the metal panel to the deck by drilling 1 1 2 inch galvanized metal screws through the peak of the rib in 12 inch to 16 inch intervals.

Begin on the left side of the roof working to the right. Stamped shingle look metal roofing is more likely to dent because there s a small air space between the metal panel and the roof sheathing. Standing seam and flat shingle roofs are in direct contact with the roof sheathing. Work toward the ridge.

There are some roofers out there that believe that since metal is such a great material and since it generally comes in large sheets making it all but impermeable they can skip the underlayment section and attach the metal directly to the sheathing. I d not install plastic on the sheathing because it s a vapor barrier.