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Tyvek or tar paper in the interior?

MartyMN_2020 | Posted in GBA Pro Help on


Looking at buying a house in Northern Minnesota with a converted garage. There is tar paper or Tyvek, looks like over plastic, on the interior. There’s ghosting in the other room too through the drywall. My concern is this set up is generating mold. I would be using the garage for my office.


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  1. Expert Member
    Akos | | #1

    In cold climates, you need an interior vapor barrier, so that is the clear plastic. There should also be a warm side air barrier, which is normally the drywall. This should not stop half way down the wall. If you are careful, you can detail the interior poly as your air barrier but doesn't look like the case here (needs caulked perimeter, taped seams and vapor tight electrical boxes).

    The tar paper on the interior does nothing except smell bad. Don't know why somebody install it there. It can be left and won't cause any damage to the assembly.

  2. MartyMN_2020 | | #2

    Thanks much. Appreciate it!

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