How should I install XPS insulation in a basement?
...XPS straight up behind the new inner framed wall and seal it to the first joist (Option 2) do I need to insulate the rim joist along that wall? (I might put some mineral wool insulation in the space to keep the floor above warmer, if there will be no condensation in the space.)
I don’t mind piecing XPS (Option 1) but ...