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moist upstairs insulation

| Posted in Energy, Heating & Insulation on January 16, 2005 09:42am

First time visitor! An accomplished wood worker aquaintance told me that this was the place for answers to my problem.

I live in a small cape in southern Maine (Portland). It was built in the 40s. My wife and I had a full dormer put in when we bought it in 1998. The dormer was properly installed (I think). The entire upstairs (including the side that was not dormered) was insulated and sheet rocked / dry walled during remodeling — as it served the prior owners as more of an attic and was not “finished”. We also installed heating.

My problem started last winter when liquid surrounded 2 of my recessed lights on the dormer side. The liquid formed a line and ran down the length of the ceiling to the wall and down to the floor.

An electrician friend told me that the likely cause was the lighting wattage was too high and that the area inside the ceiling around the recessed lighting was not properly insulated, thus we were losing heat up through the roof that was also causing condensation to occur.

I took action and added insulation around the lighting. To make this long story short, I discovered the moisture is back this winter and my added insulation is merely a sponge that is sopping up moisture! I also went into my knee wall which is “cold” and on the non-dormered side – when i reached into the insulation heading up the ceiling, there is moist insulation there as well – so this is likely not a recessed lighting issue, but some kind of moisture problem. The roof on my non-dormered side is only 2 yrs old.

Any experience/suggestions out there would be appreciated!

Steve

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Replies

  1. calvin | Jan 16, 2005 11:22pm | #1

    Steve, welcome to BT.  Is there a vapor barrier on the warm side of that ceiling.  Is the roof vented and is there an air space above the insulation.  How much insulation?

    Are you venting any baths, cooking to the outside?  Is there a basement?  Do you have alot of plants?  Running the humidifier a bit too much?  These questions may help locate the source and path of the moisture.

    Remodeling Contractor just outside the Glass City.

    Quittin' Time

  2. User avater
    BillHartmann | Jan 17, 2005 12:05am | #2

    What is between the can light and the roof?

    Most can lights are not air tight and allow relatively warm/moist air from the house to pass in the roof "attic" space.

    If the space is not vented enough the moisture will condense.

    What are the possibilities of getting right of the can lights and replacing them with track lighting or similar?

  3. Piffin | Jan 17, 2005 02:18am | #3

    Welcome into one of the raging issues of our times...

    There are three typical contributors to this sort of problem.

    Lack of a Vapour Barrier on the living/heatd side of the cieling/insulation

    Lack of adequate insulation

    Lack of ventilation in the rafter bays/attic

    You barely adress one of these and make no mention of the others.

    any ventilation that might have existed before, may have been compromised when the dormer was added
    while you say it was all insulated, you make no mention of how, materieals used, etc - some insulation can be as bad as none sometimes if it is not well done and not enough.
    even if yopu have a vapour barrier, the can light is a point of compromise. Moisture can drive past it. It must be an IC can with a seal on the trim, and that is still a maybe solution

     

     

    Welcome to the
    Taunton University of
    Knowledge FHB Campus at Breaktime.
     where ...
    Excellence is its own reward!

  4. User avater
    RichBeckman | Jan 17, 2005 04:41am | #4

    Steve,

    Welcome to Breaktime! And thanks for filling in your profile.

    Go through the previous posts and try to give answers to all the questions.

    There are three components to your problem.

    Where is the moisture coming from?

    How is it getting into your attic?

    and Is your attic ventilated properly to dry the moisture out?

    More info will get you answers.

    Rich Beckman

    Another day, another tool.



    Edited 1/16/2005 8:45 pm ET by Rich Beckman

  5. csnow | Jan 18, 2005 12:29am | #5

    A classic and common problem.

    Unsealed can lights act like little chimneys pumping warm moist air into your attic space or rafter cavities.

    If you can get at the backside, you can cheaply build sealed enclosure boxes out of drywall scraps, metal drywall corners, and caulk.  Then caulk them tight to the ceiling, and bury with cellulose.  Or you can get sealed "IC" rated lights.

    IMHO, can lights of any sort have no place in a rafter cavity.  Even if they are carefully sealed, they can still cause ice dams.

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