Originally Posted by Inland RV Center, In
The frame must be level when replacing the floor as your trying to do. Use some jacks at the rear of the frame.
Cutting the big sheets in half, weakens the monocoque construction.
How are you planning on joining the flooring at the side to side seams? That must also be done.
I have the frame supported at the rear, and the frame is level. I joined the two pieces at the back with a piece of 5/8" plywood along the bottom of the seam and glued with WEST System epoxy and screwed from the bottom into the floor plywood. The side to side seams will fall over cross members like they did in the original floor, and they too will be joined with 5/8" plywood, glued and screwed from underneath. For those of you who are not familiar with the 70s frames, the cross members under the plywood joints are 5/8" lower than the regular cross members, which allows space for the strip of plywood.
I don't intend to cut any other pieces in half, just the rear one. I probably would have been able to spread the shell enough to put the rear piece of floor in whole if I had removed more of the bolts connecting the shell to the frame, but I was concerned about removing that much support. I'm not planning on cutting any of the other sheets of plywood.