Additional attic insulation (vapor barrier) above bathrooms
longfieldl
| Posted in General Questions on
I am planning to insulate my attic, emptying everything that is already in place and making sure that there is no air flow before to add blown-in cellulose. On the floor/level below the attic, I have two bathrooms. I was wondering if this is common practice or a good idea to spray polyurethane over the bathrooms area to add extra vapor barrier for these rooms that often contain hot humid air. Is this overkill. I am living in the province of Quebec, Canada. Thank you
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Replies
Longfiedl,
I can't respond to your questions. (My suspicion is that both ideas are ill-advised.) Have you read Martin's article on insulating attic floors? https://www.greenbuildingadvisor.com/articles/dept/musings/how-insulate-attic-floor
I'd:
a) use a bathroom exhaust fan (which removes moisture and depressurizes to stop air flow into the walls/ceiling),
b) apply vapor retarder paint to the wallboard to block most of the moisture before it enters the wallboard.