I’m located in northern IL. House is 1240 square feet not counting the basement. I have vinyl siding and was only recently wrapped when it was replaced. Basement is a daylight type with one side being half way above ground. In other words about 25% of the basement is above ground. Builder left it with unfaced yellow fiber glass covered with a vapor barrier and the foundation walls exposed.

It was very damp before adding a dehumidifier and I wasn’t sure if the insulation was getting dirty or moldy and had some spots on the osb behind the insulation.

I tossed all of the fiber glass including between the joist bays. Then I cut 2 inch xps to fit between the studs and rim joist area and locked them in with can foam.  Then about half the basement was finished into a simple room. There is only half inch xps against the foundation with the framing against that in the finished area. I heard so many bad things about mold and fiberglass insulation that I didn’t want any of it.  Is it worth tearing apart to add more foam?

I would like to add more insulation to the above ground stud bays that I can still access. I was thinking of adding another layer of eps in the stud bays. Should it lay flat against the xps or would it be ok with a air gap provided by the previous foam around the xps sheets?

I know it should be covered with drywall as well. I’ve also thought about buying  more 4×8 sheets of foam and simply screwing that with the drywall to the back of the stud bays but it would leave an air gap.

I don’t feel like framing the rest of the foundation walls simply for adding insulation but might in the future.  I know it saves on heating costs but does it make cooling more expensive in the summer?

thanks

Chris