Help Needed Now --- 7/16" OSB and Metal Roof

Guest User
1/2/2010
I have a new house currently under construction. The studs, ceiling joists, and rafters are all on 16" centers. The slab is 48' x 90'. The roof is a hip roof with a 7/12 pitch. The roof has been decked with 7/16" OSB and covered with 30lb felt. The longest metal panels will be approximately 30' from the ridge to the end of the overhang. The house is in a 90 - 100mph rating according to the ASCE Wind Zone Map. 1: Will 7/16" OSB hold a metal roof without the screws pulling out? 2: Would it matter if I was using exposed fasteners, consealed fasteners, or a true standing seam that floats on clips? 3: If I install 1 x 4 purlins horizontally as a stronger material in which to insert screws then any water leaks would be trapped behind the 1 x 4s and could never escape. Knowing this, would installing 1 x 4s be worth the extra expense? 4: If I don't install the 1 x 4s, do I need to put anything over the felt before laying down the metal?
Todd Miller
Classic Products, Inc.
1/3/2010
Initial pull out tests for most fasteners are similar between OSB and plywood. You need to check with the manufacturer of any panel you install to see if they meet uplift requirements. All of the panel types you mentioned can potentially meet it. The 1 x 4's probably are not going to help meet uplift requirements -- again check with the manufacturer. In hot climates with a standing seam product the manufacturer may require a slip sheet over the felt.
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