The first question that comes to mind is the crush value of the rigid foam. If I have 2 inches below the subfloor, am I going to run into problems with the foam crushing and creating waves in the floor? I have used foam panels to insulate a slab foundation before, but once the concrete sets, it will not affect the structure if the foam moved. The walls and ceiling are obviously not a problem for this, but I am wondering if a 5/8" plywood will be enough to evenly distribute the weight to avoid any issues, or if 3/4" would be better.
Another thought pops into my brain, and that is the 2.5-3" height of the new floor will create a (minor) problem with the side door. I can always use some angle to close up the gap. In case anyone is wondering, atm I am not planning on removing the side door. It works just fine, and I see no reason to remove it. And I can see several reasons not to. The first being if I make it smaller, I will need to reskin the area where the old door was. Having limited experience with this, I am not positive about the outcome. And since it isnt broken, no need to fix it..lol I will be removing the exterior latch in favor of a 'normal' door handle (and one that can lock from the inside). I am not sure what I will find inside the door itself, it does not sound hollow. But that's a bridge for another day
