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Why do i have condensation building up on my cathedral ceiling

Bszkotak | Posted in General Questions on

Hello, I currently just built a 28’x32’ attached garage. In the upstairs i did a master bedroom with a 15’ cathedral ceiling. I installed the proper vents from the soffit all the way to the ridge cap. Then added R-38 insulation. The room is currently unfinished and unheated. The garage has been weathered in for about 2 months now. We did just have a few weeks of -20 degrees days. And i was heating the foyer in the mean time. So with there being no consistent heat up stairs, im wondering if the heat from the foyer caused it? Also my sheet rocker left a 48” x 64” window open for about 8 hours during one of those days we had cold weather. We now have puddles of water where the floor meets the wall. Im not sure if this will be an ongoing issue or what. Any help is appreciated.

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  1. user-2310254 | | #1

    On the cathedral ceiling... If this is new construction, there is probably a lot of leftover moisture. It can takes months for a home to dry out--even when using mechanical dehumidification.

    Wintertime stack effect can be an issue. Do you have any recessed lights in your ceiling? That would be bad.

    R-38 with -20 degree weather? It sounds like your home is under insulated.

    1. Bszkotak | | #2

      R-38 in the ceiling. R-21 in the walls. And no recessed lights in the ceiling. The Rafters are 2’ x 12’, so R-38 was all i could fit in the bays. -20 isn’t something we see on a normal basis. It was a few select days where night time temps dipped way below zero. Im in upstate NY and we average just above 0 degrees during winter months.

  2. Expert Member


    The chances are every good this is entirely due to the conditions during construction, and once complete you will have no further problems.

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