I realize all the info we need is on this forum.... Somewhere
(the rabbit trails get overwhelming for me at times- TOTAL respect!).
Anyhow, I saw an Article last year that spec'd these materials, below. Not sure if this is in contradiction to what the Altro Transfloor rep told me or not (wanting flex in the flooring in a van)
Here is the flooring base info and he used laminate and that is free floating
*Cut and install foam board insulation
For the floor 4′ x 8′ sheets of 1” rigid foam insulation works best- pink sheets that will support some weight.
** Place Oriented Strand Board over the foam insulation
Lay 4′ x 8′ sheets of ½” OSB (oriented strand board) on top of the 1″ rigid foam insulation.
Although OSB doesn’t have a natural grain, look at the way the wood chips are aligned and make the longest side run from the front of the van to the back.
You’ll install the finished floor layer crosswise later on. Running them perpendicular to each other will make the floor more rigid.
OSB is similar to plywood, but costs less and has more strength. It’s usually used in housing construction for load-bearing applications.