Teardrops n Tiny Travel Trailers

I got the old plywood up from the floor and.....what is this. The floor is insullated . There is a sheet of aluminum layed on the chassis fram then a thin layer of birch or other thin wood sheet. Then the fiberglass insulation. It looks like it was sprayed in because it is stuck to the aluminum. 2x2 pine support framing is next and finally the plywood floor.
Now my question is this. With the alumunum being torn up and other wise mutalated it is going to have to go. Can I lay is some 7/16" ply, that I seal, dirctly on the trailer chassis then do the support framing on that? I just don't understand why the alumunum was used in the first place. It seems it would hold water. This is probably why the floor is dry rot around the whole perimiter.

That's exactly why some don't recommend puting something like aluminum on the bottom. Water probably got between the ply and aluminum and had no where to go. As far as putting ply directly on the trailer and then frame on top of it, a lot of people do it just that way.

It seems the wood on the frame would be the best bet. It will make getting the old floor out a lot easier. I will just use the saws all and run it around the perimiter then dig out the left over stuff. I think I will have to remove the left overs in sections so the walls don't fall. Am I right?

I will finish installing the new floor this weekend. I opted to not insulate in as the ply is 15/16" thick. If after using the trailer we find it is just to cold (walls and ceiling will be insulated) I will tack down 3/4" fir strips to the floor, fill the spaces with ridged foam and lay 1/2" ply over it. I doubt I will need it though.