jeff wheeler
4/2/2013
I've got a covered deck with metal roof.I enclosed it and now it sweats.2 x 6 rafters-10x14 deck-2 in. drop in 10 ft.-built off of a trailer.Will insulating it with 6 in.of insulation stop the condensation?
Todd Miller
Isaiah Industries, Inc.
4/3/2013
Can you add a vapor barrier in addition to the insulation?
jeff wheeler
4/3/2013
I can take the roof off to add a vapor barrier.Was tying to avoid that.
Todd Miller
Isaiah Industries, Inc.
4/3/2013
I assume you're planning on the insulation beneath the roof somehow. I was thinking maybe a vapor barrier beneath that. Chances are the insulation will have a big impact but unfortunately I can't say for certain that it will end the condensation.
Eric Novotny
An informed customer is the Best Customer!
4/3/2013
+1 Are you talking about on the roof deck or to the underside? 6" of what type of insulation. Without knowing those details it is impossible to say. You do want to apply some sort of moisture (vapor) control layer but how much and what type depends on what you have existing and what you are proposing.
jeff wheeler
4/7/2013
What type of vapor barrier could I use ?Then I:ll use 6 in, of fiberglass roll insulation,(all on the underside)It will have some sort of ceiling .
Todd Miller
Isaiah Industries, Inc.
4/7/2013
Can you put a layer of polyethylene behind the ceiling? Or else get insulation with a built in vapor barrier and tape the seams.
Eric Novotny
An informed customer is the Best Customer!
4/7/2013
The vapor barrier should be across the insulation in this case if you are going to go with batt insulation. If not, the moist air will percolate through the insulation and still hit the cold underside of the vapor barrier and condense. http://www.buildingscience.com/documents/digests/bsd-119-summer-condensation-problems-in-ice-arenas/?searchterm=metal%20roof%20vapor%20barrier
jeff wheeler
4/8/2013
Thanks for the advice.
Tom Jaklitsch
4/22/2013
I have major issues with condensation from my indoor clay court tennis metal building. I have a hanging 6 inch insulation system that is 5 to 8 feet from the roof deck. The roof has no insulation under it. The condensation is at its worse from 9am to 1pm on sunny cold days. My roof is almost 40 years old. I plan on re-roofing over the existing roof. My metal building contractor said that I must insulate either under the existing roof deck or insulate in between the existing roof and the new metal roof overlay. It is impossible to roof under the deck at this point because the insulation system is in the way. My question is...will the insulation between the two metal roofs prevent this condensation. (The air existing air gap between the insulation and the deck is well ventillated).
Eric Novotny
An informed customer is the Best Customer!
4/30/2013
Insulation over the top of the old roof and in between the two systems should help raise the dew point and eliminate some of the condensation potential. Pictures and location will help get you much more directed and fundamentally sound answers.

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