How to properly insulate bf Laying hardwood over extension
I just purchased a new home. First off, the house had some significant termite damage. Next, we realized after tearing out carpets that the hardwood oak floor in the dining room stopped at what was the original front wall. Apparently the previous owner extended the dining room 6 feet out (by 13 feet wide) over a slate and concrete covered stoop or porch. They have the floor joists (2 x 10s) sitting vertically right on the slate / concrete. The subfloor (which was termite damaged) has been ripped out. I want to insulate and properly moisture proof before laying new sub-floor and hardwood to continue the dining room floor.
What would you suggest?
Can i lay rigid insulation down directly on the slate / concrete? Home Depot rep suggested caulking that to the joists to seal moisture down... Then laying wall/attic fluffy insulation on top of that and then the subfloor on top.
I also bought vapor barrier that looks like black contractor bag material to lay on top of the joists under the ply wood subfloor for extra vapor protection.