GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

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

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.

Replies

  1. user-2310254 | | #1

    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

  2. Jon_R | | #2

    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.

Log in or create an account to post an answer.

Community

Recent Questions and Replies

  • |
  • |
  • |
  • |