I’m replacing a 30 year metal roof with EZ Snap 16 inch metal panels. This is a Gambrell Roof - 7/12 to 18/12 to 5/12 pitch with 7/12 to 5.5/12 pitch transition at the dormers. The old roof was damaged from snow and ice ripping the exposed screws out of the panels. We average 30 feet of snow here plus rain. So it’s important to keep the snow moving. I’m in an isolated community. Supplies are 300 miles away. So I’m trying to work with what I have.
The existing joists and rafters are 24inch centers. The panels are 16 inch. The sheathing is 1/2 CDX. I’m using 1" pancake screws (couldn’t find any shorter). I’ve completed 1/2 of the roof (the carport side).
Pancake screws are set at 12" on center. Quite frankly I didn’t realize the sheathing was 1/2 inch until I started the project. I’m about to replace sheathing on the 5/12 pitch located below two dormers (East Side) as the sheathing is weak and one piece was rotted. This area of the roof is over a living area. Before I place my order I have a couple questions.
I’m beginning to have visions of the panels lifting up in a few years from wind (gable trim should help here, the current roof doesn’t have any) and snow and ice dumping off the dormers to the lower 5/12 pitch roof.
Will the roof survive with 16 inch panels secured every 12 inches primarily to 1/2 CDX plywood?
If I replace all the sheathing on the East Side with 3/4 or ? what other dimensions are changing that I havent’ thought of i.e. distance between roof and bottom of Dormer window?
Pics of roof are at:
Thanks for your help!