I am planning out the finishing of a bedroom in the unfinished section of our basement. The house is new-ish being built in 2005 and located in MI.

One of the walls is an exterior, poured cement half wall about 40" high, then framed, insulated and drywalled above that. The framed portion is recessed about 1" back from the cement lower portion. I want a smooth wall floor to ceiling, so my plan is to frame the entire wall height. I have been searching for the suggested way to frame and insulate this and here's what I am thinking:

3/4" XPS over the cement, standard 2x4 framing in front of that. That works great for the lower cement section, but my question is how to handle the upper section. I understand that I do not want any air gap behind the wall, so I am thinking of two approaches: first would be adding the 3/4" XPS To the lower section only then framing in front of that. Then add FG batt from flooor to ceiling with it filling in the extra 1" gap on the top half.

The second approach could be to first add 1" of XPS to the top half of the wall to bring it flush with the lower cement face. Then I can add the 3/4" XPS floor to ceiling, then the framing. Does that make sense, or is there a better way? Seems like that would result in a fairly weird top half since the existing framing, insulation and drywall would then be covered over by more XPS then framing then drywall. Like a 2 wall sandwich.

Thoughts on these two approaches?

Thanks in advance!!

This post was edited by dymaxion on Wed, Feb 13, 13 at 23:10