Will this assembly give me vapor issues?
Hello GBA community, Finishing an unfinished loft and garage and want to make sure I don’t create any vapor issues. Both will be heated and cooled with a mini split. The garage will be kept at 50-55 in the winter. If you look at the attached diagram of insulation and vapor/air barriers, I have a few questions. The XPS in the roof bays will be foil taped at edges/seams.
1. Will taping the outermost XPS create any issues?
2. Will the ERV be enough to prevent moisture problems in the attic spaces (left and right of loft)
3. Based on above, can I leave attic spaces separated from loft or garage or should I allow ventilation between those spaces
4. Will taping faced insulation be sufficient for vapor/air barrier between garage and loft and attic?
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Replies
New London80,
It's hard to say. It's very hard to predict how attics with insulation on two sides will function. Those not inside / not outside spaces can have moisture problems, and the best strategy to avoid the risk is to have a clearly defined thermal boundary, by picking one side or the other, and putting all the insulation there.