My father in law had an energy audit with a rebate program in Colorado. He is looking to improve insulation/seal of rim joist in basement. We don’t have many basements around here, so I am not sure what is the best way is for him. I suggested spray foam, but that was too expensive. So my next thought was 2 inch R board cut to fit and some can spray foam to seal in place. Any concerns on trapping moisture? Is there an easier way? Thanks for any advice.