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.