I am redoing my basement and was wondering how to seal the wall vapor barrier if there is no existing vapor barrier from the floor above. Or is it better off not using vapor barrier ? I am from Manitoba and it is very humid and I don't want to have anything rot because of the moisture being trapped.


Vapor barriers tend to be one of the most hotly debated topics in home building. I redid a basement in MN a few years ago and ultimately went with Building Science Corporation's recommendation which would apply to your climate as well. See this answer for details: https://diy.stackexchange.com/a/8644/1209

Summary: Do not use a vapor barrier. Instead use EPS or XPS foam for your insulation which will act as a vapor retarder, but not trap moisture like a barrier would.

  • Mike Holmes even likes putting XPS down on the floor – Steven Dec 15 '13 at 23:16
  • If built right in the first place (generally too late when they show up here) you put the XPS UNDER and OUTSIDE the basement floor and walls. – Ecnerwal Dec 16 '13 at 1:40

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