TOPIC: I Have An Existing Metal Roof and Have A Question
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Hello- we are building a house in Vermont, and had a standing seam roof installed (whole roof & second floor were new) in July. We havent had any leaks or water with any rain or snow until this past weekend (the -20 degree weather).
Our roof is cathedral and vented, with baffling from new soffits to the ridge cap vent. We see little rivulets of water on the moisture barrier (right now we only have baffling, insulation, and moisture barrier installed).
Is this an issue with the ridge cap/ice build up? If so, how do we rectify this?
So, you do not have any finish on the ceiling such as drywall or something? Is that correct.? What is eventually planned? Tell me more about the placement of this moisture barrier. Also, what exactly is it? My first thought is simply that moisture is getting places it won't get once the structure is completed but I'd love to know answers to these questions. I assume you're heating and living in the structure now?
Thanks Todd for the quick response!
Yes, we are currently in construction, but living on the first floor. Yes, heat is on in the house.
The ceiling will be pine boards tongue and groove. The baffling is the pink kind, the insulation is mineral wool, and the moisture barrier is 6-mil plastic which was recommended by the mineral wool manufacturer. This plastic is across the entire ceiling (basically the first thing you see when you look up). I also installed internal metal screening where the soffits come into the stud bays and up by the ridge cap vent in each bay.
The water rivulets does not seem to be just condensation, as it is running down and coming out on the lower ends of the cathedral ceiling (such as where un-trimmed windows are), and dripping through the holes in the plastic where we have wiring coming out of (don't worry, everything is disconnected).
Literally this weekend was the first time this has happened.
Thank you. This is very helpful.
The standing seam roofing is on solid decking such as plywood I assume?
Yes- plywood, ice & water shield, then metal.
Well, I tend to agree that it doesn't sound like condensation. That said, condensation in the right (or shall I say "wrong") circumstances can create a lot of water.
So, if the ventilation is functioning properly, the ridge vent should stay clear. If the ridge vent has gotten covered with snow or ice, that certainly is an indication that something is awry.
Ideally, you want about the same NFA of intake vents as exhaust, perhaps a little more intake in fact to pressurize the attic a bit.
Ventilation that is functioning well will keep pushing air and weather away from the exhaust vent.
Could this also happen if the metal isn't pushed up far enough into the ridge cap?
What would be your advice for the first step in us diagnosing this?
You raise a good question. Getting some sort of diagram from the roofer showing exactly how the ridge was finished is a good idea. Yes, water / snow / ice could be getting by whatever closure was put at the ridge. Ideally the closure will not allow that.
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