Yesterday I found a plastic panel material that was in stock locally that was almost perfect for AS floor replacement. It is $57.20 per 3/4" x 4' x 8' sheet and it is virtually indestructable. The catch (and it is a big one) is that it is not stiff enough. I do not know how it compares to the CoDeMo panels as far as stiffness but it is sure floppy. When you let about 3' of a sheet of 3/4" plywood overhang the stack it basically sticks out straight. This stuff sags 6 to 12". Anyway you can take a look at the information about the product at the following web site:
The product is called Polyboard. Some of you reading this might have other uses for it besides for your AS floor. I can think of some other uses.
The material is not billed as being a structural material. The "General Installation" tab is the only place I could find where it talked about span distances in horizontal uses. It said there not to exeed 500~600 lbs load carrying weight. It also said that supports should be at a minimum of 12 centers to prevent deflection. Yes, It did say "12" too without any units mentioned. I assume that they meant inches but who knows. I do not understand enough about the structural details in their chart in the brochure I picked up to know what the deflection numbers mean. Maybe someone reading this could comment and perhaps compare it to plywood? The table said the following about the material:
dimensional stability - load deflection = 1.42 * 10-2 of span (the -2 is the negative power of)
I could envision adding additional support so that the maximum span was 10 or 12 inches if that would work. What I would be more concerned about though is the issue of how much structural support is the plywood actually providing (and needing to provide) to the bottom of the walls along the sides of the AS. My observation is that the plywood must be working with the outriggers to help support the bottom of the walls. That is likely to be one reason the original plywood was installed cross wise to the frame for more support to the ends of the outriggers. I guess I could envision doing something to beef up the support for the outriggers too. I just don't know how much extra support would be required and just where. Of course extra support adds to the cost of the solution along with the extra work involved.
If the support problem could be resolved this material seems like it would be really great.