Hi there. I am starting a DIY 4 season porch In Minnesota and I am not sure how to finish the floor. The current joists are 2" x 8", 16" on center. The bottom of the joist are only about 12" off the ground, so it is not possible to get underneath to insulate. So, we are planning on running 1x6 deck boards on the underside of each joist (full length). Then, I will need to drop down some plywood first before insulating. My question is, what would be recommended for the plywood. I found this and was wondering if this would be sufficient:
Moisture Resistant Plywood Underlayment
Or do I have to use some sort of treated plywood? Also, would you put some plastic down before the insulation? As for insulation, I am thinking of doing a layer of sheathing before throwing in some fiberglass insulation. Is this all overkill? I am open to suggestions and tips. I am sure more questions will follow!