5V metal roof over SIPS: ...: "Hello - I have a real issue with a building ..." - J. Holcomb (1/17/2016) | I Have An Existing Metal Roof and Have A Question

Hello - I have a real issue with a building roof involving 5V metal over SIPS: extreme expansion/movement causes SIPS to rise and fall. It's a 10-yr-old roof (approx. 50'x100'), in full southern-exposure sun. Construction is 8'x16' SIPS, 8" thick, spanning 16'. On top of that are 2 layers of 30# felt, and polypropylene laminate roof underlayment. Roofing is 5V galvanized, screwed in the flats. We are measuring at least 1/4" rise in the center of the SIPS during mid-day sun. The metal roof appears to be pulling the SIPS up. This daily rise and fall is causing enormous noise in the post-and-beam construction, and the fear is that it may also be causing permanent structural damage. SIPS manufacturer has acknowledged their specs for spanning were inaccurate (panels are overspan). Question: what might be the best approach for minimizing the expansion/rise of the metal in this situation? Addition of venting? Re-roofing with screws through the ridges? Any advice will be greatly appreciated.		J. Holcomb 1/17/2016	Share Or copy this URL: https://www.metalroofing.com/spirit/comment/20936/find/
Some more above deck venting might do the trick. Between that and attaching the metal to the pulins, that should keep the SIPS more isolated from the metal.		Eric Novotny An informed customer is the Best Customer! 1/18/2016	Share Or copy this URL: https://www.metalroofing.com/spirit/comment/20937/find/

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5V metal roof over SIPS: expansion