Condensation at peak of vaulted/cathedral ceiling
I was wondering if I could get some advice regarding condensation on the vaulted ceiling in our bedroom. My wife and I purchased this house last fall (est. 1840, in Western NY) and have started to notice what looks to be condensation at the peak of our bedroom ceiling. It seems to come and go depending on the time of day. It’ll be dry in the morning and dripping by the afternoon, same results the past 2 days. I will try my best to describe the infrastructure:
One slope (west) of the ceiling is butted up against the roof rafters while the other slope (east) of the ceiling is up against the attic rafters. There is a portion of the master bedroom (south) where the ceiling is flat, which is adjacent to the attic slope. Access to the attic is through a man hole in the flat portion of the ceiling. This attic space runs the entire length of the house (north and south). The ceiling in our spare bedroom (north) is also vaulted with the same layout. (The provided picture is a cross-section of the upstairs of the house. Disregard the measurements labeled on the picture)
The first thing that comes to mind is poor attic ventilation. There are 4 “box” vents along the attic side of the roof. There is no ridge vent, no soffit vents. There are 2 gable vents, 1 on the north side and 1 on the south side. The south one is completely enclosed (for reasons unknown), obstructing any air in-flow from that vent. The north one is partially obstructed by a ceiling rafter. There is fiberglass insulation laid along the flat portion of the ceiling and up along the east facing ceiling slope. I don’t believe there is insulation on the west facing slope where the ceiling is up to the roof rafters. The previous owner did stuff insulation in the gaps where the ceiling starts down the western slope.
We have tongue and groove pine for ceiling material, which I know tends to be “leaky” in regards to air flow. The previous owner used what looks like black caulk around the creases and seams where the ceiling meets the wall, both up in the attic and in the actual room.
The roof seems to be in decent shape from an exterior point of view. I’m not sure how much of this issue is having a possible “leaky” ceiling, having poor attic ventilation or a combination of both. I’m also not understanding why the condensation is accumulating on the “cold”, or room side, of the ceiling. The attic is warmer, the bedroom is cooler (no AC). I figured condensation would accumulate on the warm, or attic side? I don’t see any signs of immediate moisture in the attic under insulation or around the ceiling rafters. There are colonies of white mold that have started to show up along the roof rafters in the attic, more so on the south side towards the gable vent that is completely closed off. I plan to do whatever work myself, and would like to address it ASAP.
Any tips or advice on which direction to go from here is greatly appreciated. I can provide more picture if need be.
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