Ok, so I am getting different answers everywhere I ask. I have a 15x15 foot addition on my house which was once a porch. It is now fully enclosed, insulated and studded walls, new windows sitting on 2x10 inch joists at 16 inches on center sitting about three feet above ground with the exposed space below open to exterior elements. Lattice is around the perimeter posts. Interior floors are tiled.

My question is this, after pulling off the plywood from the bottom of the joists beneath the structure in the exposed open space above the exposed ground, I found that it is insulated with R30 fiberglass batt insulation with the vapor barrier paper facing the ground and not up against the interior floor. That seems wrong to me but I am not an expert. Also, the plywood that is put in place covering the joists and fiberglass from below is not ventilated...is that a problem? I was thinking of pulling the insulation and then cutting and putting 2 inch foam between the joists up against the bottom of the subfloor and sealing with spray foam where any air leaks appear and then put the R30 batt insulation back in place and then covering all again with the plywood I pulled off.

So it would look like this from the top down: the interior floor and subfloor, then the 2 inch foam underneath and then R30 next and then the plywood to cover the joists from the ground about three feet below.

I was just concerned with the vapor barrier issue. Should I pull the paper off the R30 and place the fiberglass directly against the subfloor and then add the 2 inch foam between the joists below the R30? Would I use a 2 inch foam with a vapor barrier side? Which way would that face?

I am getting answers both ways concerning the facing of the insulation. Some say facing should be against the warm side (flooring) and others have said the facing should face down and stapled to the edges of the joists.

Any help would be appreciated.

Thanks!