Insulation installation / Discussions

I need to insulate my basement walls in between the floor joists of the upper floor. I am thinking some panels sealed in with insulation foam adhesive  For insulating the floor joist cavities in basements, you can use foam panels and you suggested. It can be busy work with a lot of cutting, but it works well and it is ...

...insulation job. My concern with leaving a large, contiguous air gap is that mold has potential to grow between the stud walls with the rockwool insulation and the closed cell spray foam.  My concern with trying to fill the void will also likely have air gaps and the rockwool gets pretty beaten up when stuffing it betwe...