New home — attic moisture
Our 2 y/o old home has had moisture issues in the attic since we moved in. It's a Cape-style home with closed-cell foam insulation and touted as a "tight" efficient home.
I noticed moisture on the roof sheathing, small spots of green and white mold, and rusty nails in the attic and musty stagnant smell in the upstairs bedrooms in the summer. I hounded the builder and original insulation company the first year. There were a few issues that I thought may have contributed but they were corrected; i.e., disconnected dryer vent in first-floor joist chase, poorly sealed bathroom exhaust in kneewall space, and a 3rd floor bathroom exhaust that traveled too far across attic.
Since then that bathroom exhaust has been vented directly through the roof. 3rd floor has kneewall entire length of house from and back. Attic ventilation is soffits with ridge vent.
Anyway, its been cold and snowy here, finally we had a slight thaw, we came home to water dripping from north gable ended window casing in 3rd floor bedroom. I inspected the attic and found frost on mainly north end gable sheathing and some rafters. The frost melted and leaked down into bedroom finding its way out the window casing.
The humidity in the house is low, dehumidifier barely collects any water, although we have condensation and frost on windows in the winter. I also noticed moisture in between foam and batt insulation on gable ends in kneewall space.
What gives? Is it an air seal issue from kneewall space to attic?
Posted Wed, 01/08/2014 - 21:18
Edited Thu, 01/09/2014 - 06:26
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