Did an older home yesterday. The batt insulation had a very thick, non-porous, vapor barrier (it was not Kraft paper) against the ceiling. On top of that, they added another layer of batt insulation with the vapor barrier face up.
The ceilings had yellow streaks throughout the house. There were no signs of leaks. The attic was not well ventilated (only 2 gable vents.) Below is what I said in the report. Does this sound reasonable? Could there be any other cause for streaks? (Sorry, a photo in the living area does not show the ceiling stains well.)
“The thick, non-porous, vapor barrier in the attic traps the rising moisture next to the ceiling. The result is condensation and subsequent moisture stains on the ceilings below. We can elaborate, but we suggest that you have an insulation specialist comment on the current installation method and consider complete removal and re-insulating the attic.”
“The attic is insulated with multiple rolls of batt insulation. The multiple vapor barriers trap moisture next to the ceiling and may result in condensation and subsequent ceiling stains. We can elaborate, but we suggest that you have an insulation specialist comment on the current installation method and consider complete removal and re-insulating the attic.”
Photo 2 shows the vapor barrier which was against the ceiling. Photo 3 shows stains on the attic side of the ceiling.