I have an old home built on a stone foundation. The stone foundation is solid, as well as the floor joists. I run a dehumidifier in the basement full time, to keep the air moisture low. There is never any water in the basement. The floor is dirt with a covering of gravel. There is currently some fiberglass insulation between the floor joists (installed incorrectly, paper backing facing down), and a foam insulating board nailed to the bottom of the floor joists.
I was advised to flip the fiberglass over, so that the paper backing is facing the living space, instead of facing the basement. If I am going to do that, should I do anything else with the fiberglass at the same time? Should I put plastic sheeting in? Should I wrap each length of fiberglass in plastic, tape it shut, making a bag of insulation in each floor joist void?