Recommendations on this basement wall & rim joist detail!? – GreenBuildingAdvisor

Hi all,

I am located in Ontario, Canada, and currently finishing my basement.

The norm here in Canada has been to put 6-mil poly on the interior ‘warm’ side of basement walls… I understand the building science behind this ‘standard practice’ is flawed (greater water movement through air leakage vs diffusion, heating vs cooling of basement depending on seasons, limited drying potential of wall etc.).

If I could choose to detail the wall assembly again, I would’ve gone continuous rigid foam to act as both the vapor/air barrier, however interior stud furring walls are already in place and poly is up. 

What are your recommendations for making this wall/rim joist detail better… or less bad? I was going to switch out to rigid foam for rim joists while maintaining the poly over the stud wall. The exterior 1″ insulated sheathing runs over rim joist, but not doing much thermally.

My biggest concerns are the drying potential for both rim joist and wall cavity, since eliminating moisture within the wall assembly is a near impossibility. 

Any recommendations would be greatly appreciated, while limiting the amount of rework.