I have a low slope roof (approx. 5′ in 60′) that was covered in 4’x60′ sheets of galvanized metal and screwed only at the lap 4″o.c. with neoprene washer screws and sealed with silicone in the lap. These joints and some corners are starting to fail due to thermal buckling and age (20yrs). I was thinking of replacing the roof with epdm, but one contractor said to screw the iso. board 16″ o.c. right over the metal and then apply epdm. I am concerned that there might still be significant movement under the rubber. The metal is on top of 4/4 rw boards. Should the metal be removed or not? Is there a better way to approach this problem? Thanks for the help!
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Just to get things rolling....
I certainly do not qualify as an expert.......but I don't see any reason why the metal needs to come off. Is the lap of the metal flat instead of ribbed? Ribs would complicate things, but seems doable to me.
Rich Beckman
Hi Rich,
Yes the laps are flat. But there are screw head protrusions of about 3/8ths +/- of an inch.
ken
Well, I guess an argument could be made that the screws should come out first, 3/8" being a bit tall if you're putting down 1/2" board. But maybe you're using a thicker board?
I would try putting down a board first and see how it looks and feels before deciding. But I'm thinking that 3/8" is too high for the 1/2" board (and maybe thicker board, too). Once you're pulling the screws, is taking the roof off that much harder?
Again, I'm no expert. Seems like someone around here would know better than me (most everyone I'm guessing).
Rich Beckman