TOPIC: I Have An Existing Metal Roof and Have A Question
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Question: should my roofing contractor have applied some sort of sealant where two panels overlap at the major rib (in the anti-siphoning groove area maybe)? My roof is about a 3 pitch, and is sort of a semi-cathedral ceiling, in that it slopes from about 6' to 8', and is just a "slab," i.e, rafter with sheathing/roofing on top, and drywall beneath, with insulation in between.... no airspace. He did not apply an ice-barrier membrane.
Reason for asking is that there is a fair amount of ice buildup at the lower edge of the roof due to the heat loss through this ceiling/roof, and even with heating cable to create channels for water to drain through (cable goes beside each major rib, up one side and down the other side,) I keep getting icicles forming not just at the edge, but also "inboard" of the edge, right up almost against the wall, and sometimes even onto the window screen... and water keeps dripping from the window casing at the top, and also from where the wall meets the ceiling (there's a big 2x10 triple-sandwich 'beam' there.) It isn't constant, but when it's really cold outside and warm inside (big contrast in temperature,) that's when the water starts up.
My thought is that despite the cables, water is still backing up, and finding a way into the ceiling through the roof panel overlap, because there's no sealant in it. Nothing I can do about it right now, but come Spring, I'll probably be: A.) pulling up the panels, B.) putting down ice/water barrier membrane, and C.) putting sealant in the rib overlaps.
Took 3 quick pics; they don't show the roof (buried under a foot of snow,) but this is what the leakage looks like from the underside:
Thanks. To try to help with this, we really need to see photos of the roof without snow / ice on it. Thanks much.
You would have to see the unobstructed roof to answer whether using some kind of sealant where the panels overlap is industry standard practice, or recommended on low-pitch roofs? That seems odd.
If that's the way it has to go, though, guess I'll be back sometime in late Spring.
If we are talking about a mechanically attached roof in something like an R-Panel, they are only intended to be used on certain minimum pitches. At that point, there are applied butyl sealants that can go between the panel lap joints, but you are ultimately asking for trouble if you are depending on a glue/caulk joint.
Thanks... that's what I was looking for. As I mentioned, the roof pitch is only a 3, and there's no air space like in an attic. It's roofing, sheathing, 2x10s, insulation, and drywall. Sheathing applied to rafters on one side, and drywall on the other side.
Don't look at me, I didn't build it!
I'm guessing that ribbed sheet metal roofing panels was probably not the way to go here. I was just replacing like with like; the old roofing had tree limb damage, 'blackjack' slobbered on it here and there, and lots and lots of nails and screws and holes where a nail or screw used to be.
Any suggestions on what would be a better alternative for such a ceiling/roof?
This is the product he used:
Not sure that worked, so here it is again:
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