New insulation wet?
#1
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New insulation wet?
So I had my 80 year old house insulated a year ago - blown into the walls on the lower levels and rolls of insulation between the joists in the attic because I'm planning on finishing the space. The attic insulation was then covered with a sheet of plastic. Since it has warmed up this year, an enormous amount of condensation has formed on the inside of the plastic in about 3/4 of the space and it feels very humid in there. The same thing happened last year and the contractor came out and replaced half the insulation, thinking they maybe put damp insulation in there to begin with. Any ideas on what could be causing this and what can be done to remediate it before I develop a mold problem in there??? (Roof is not leaking...)
#2
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Welcome to the forums.
The plastic is on top of the insulation? The moisture is coming up from within your house and the plastic is trapping it there.
The plastic is on top of the insulation? The moisture is coming up from within your house and the plastic is trapping it there.
#3
As Mitch said, your vapor barrier should have been below the insulation. Having it above creates a "pot lid" that will trap condensation. Get rid of the plastic.
#4
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Actually, given that you plan to finish this space, I think you ultimately want the insulation above the attic, not in the floor.
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Let me clarify - the condensation is on the inside of the plastic - between the insulation and the plastic barrier they covered it with. And it is on the ceiling of the attic - I probably used the wrong terminology. Definitely not anything close to a professional!
#7
They are not called joists, they are called rafters.
I think the question now is how deep are your rafters and how deep is your insulation? In your installation, there should be a gap between the insulation and the roof deck to allow ventilation from vents in the soffit to vents at the peak of the roof.
I am going to make an assumption based on the age of your house. I don't think your rafters are very deep at all and the insulation was possibly installed against the roof deck. If that is the case, then I am pretty sure that is your problem. Especially if you have vents in your soffits and at the ridge that would allow moist air to flow between the rafters during the day, then when things cool off at night, it condenses onto the plastic.
I think the question now is how deep are your rafters and how deep is your insulation? In your installation, there should be a gap between the insulation and the roof deck to allow ventilation from vents in the soffit to vents at the peak of the roof.
I am going to make an assumption based on the age of your house. I don't think your rafters are very deep at all and the insulation was possibly installed against the roof deck. If that is the case, then I am pretty sure that is your problem. Especially if you have vents in your soffits and at the ridge that would allow moist air to flow between the rafters during the day, then when things cool off at night, it condenses onto the plastic.