Cold climate (6) standing seam metal roof leak
I have concerns my entire roof is leaking due to improper detailing of my standing seam roof. I also think this discussion could help others who might be thinking of a standing seam metal roof. They are not what they’re all cracked up to be. Please look at enclosed photos.
I have a shed roof (Structure are I-Joists) with a 3 1/4: 12 pitch. R-60 insulation in cathedral ceiling–“flash and batt.” “Flash” is 4-6″ closed-cell polyurethane spray foam. Hot roof: Fully Zip taped, Zip sheathing and GAF underlayment. And finally: 1″ single-lock standing seam Galvalume.
Lots of snow build-up over winter. Due to the pitch and the amount of insulation, there are no conditions where snow slides off on it’s own. Eventually ice builds-up over top of the seam. As weather gets warmer, water is observed dripping out underneath of overhang (sofit) on low part of the roof. My guess is the entire roof is leaking at the standing seams and water is sheeting down roof plane, over underlayment.
Will a double-lock fix this problem?
My fear is if I double-lock the seam, I’m committed to the detail and it may still leak. At this point–with a single-lock–I could probably take it apart piece by piece and mitigate the problem. Roofer suggested I clear snow off after every storm–which is not a long-term solution–it’s just plain dangerous. It’s also a “green building” so I’d rather not use heat cables to clear the ice all winter –that would be an admission of failure. I’d like a 50 year solution–which is why I got the metal roof!
Having done some research recently I’ve discovered a 2-3″ tall standing seam with a butyl sealant at every seam would have prevented this from happening. But it’s too late for that.
As it is now, if I can probably take apart the roof–one 30′ section at a time, cover the Zip sheathing with a waterproof underlayment, then re-bend each seam with sealant and a double-lock.
And finally, does anyone think my roofer is at least partially on the hook for my roof leak? He says he’s never heard of this happening before.
Thanks so much for your comments.
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