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Community and Q&A

Ice Dams and Attic Mold

Sac_78 | Posted in General Questions on

We bought a brand new condo , built 2018 a couple of years ago in Massachusetts.  There is a valley( between me and my neighbor) at the back of the home on the roof,  where there was a ice dam and I came to know because I saw discoloration   in the my corner of living room and in my bedroom above it .  My neighbor ,the previous day , had  HoA management company  remove dam from the front of the home.

I went to investigate and there there was mold growth in the attic but per what I saw there was  nothing in the corner. The area around the baffles was wet and  the mold was growing around it mostly.  There was water condensation on the ceiling of the attic and on nails.

First I am very concerned, quite disheartening,  at this is a  brand new construction, and secured after much effort and search.
HoA for now, feels this is a ventilation problem(they came into attic). Our Condo has soffits, baffles and ridge vents . I have asked inspector to come in . Any idea what could I do here as this is a new construction . Should I inform builder.. The  humidity level is at 80% in attic. The insulation is blown in cellulose and beneath the cellulose is the dry wall( I guess with plastic covering ) on it.

What can we check for and do?


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  1. 1869farmhouse | | #1

    What’s the basement/crawlspace situation? Or is this unit on a slab? Often times, below a moldy attic is a damp crawlspace.

  2. Jon_R | | #2

    Do a search for info on stopping (vs removing) ice dams. If they cause water to enter the attic, it will be moist up there until it dries out.

  3. Expert Member
    Dana Dorsett | | #3

    Ice dams above a floor-insulated attic is a heat leak issue. Dripping condensation on the points of roofing nails is usually an air leak issue. (Air leaks from conditioned spaces into the attic are also heat leaks.)

    I'm not sure if you personally can take this to the builder to make them rectify the problem, but maybe. This would take a legal consult to figure out.

  4. Expert Member
    BILL WICHERS | | #4

    Small amounts of mold can be dealt with by spraying bleach solution and some scrubbing with a brush. You don't have a huge mold issue here, it's still pretty manageable. The issue you have is how the mold got started, which is probably air leaks as Dana mentioned. I'd also check that there is ice and water shield going high enough up the roof (usually at least TWO courses, one isn't enough). If your ice dam gets up higher than the ice and water shield, you can have melt water getting under the shingles and ultimately wetting the sheathing and leaking into the attic.

    Your pics don't look like they show problems with melt water getting in (no big dark wet spots), so its more likely you have interior air leaking up into the attic and also possible insufficient ventilation or blocked vents.


  5. GBA Editor
    Kiley Jacques | | #5

    We have a few Q&A Spotlight articles about ice dams and the conditions that create them. They include some valuable information from technical advisor Peter Yost and some relevant resources. Reading them could give you a fuller sense of what might be going on in your case, and how to address it: Heading Off Ice Dams Before They Form and Heading Off Ice Dams.

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