You drive the screws in just enough to slightly flatten the rubber 'washer' forming a seal, but not enough to bend the metal.......I just put up a small piece of this roofing this morning.Quote:
......I didn't put them on the high parts... those peaks aren't even touching the OSB... wouldn't that have bent the roof all up? .....
But from googling it's a much debated issue weather to put them thru the ribs or flats....so you might just need to caulk all your screw heads.