Re: Treated plywood for flooring?
The problem with treated plywood for boat building is that it has a high moisture content from the chemical solution they use to treat it. It needs to be a kiln dried treated plywood, especially if you're going to apply anything to it like resin or glue.
The standard grade exterior treated plywood will also have quite a few voids inbetween the plies.
You would probably be better off to go with the kiln dried CDX plywood, it'll have just as many voids but will be dry for your resin application.
This is what happens when you apply resin or glass over PT that hasn't been kiln dried.
http://forums.iboats.com/showthread.php?t=500296&p=3372728&posted=1#post3372728
Your resin won't absorb into the wood, will probably turn milky, won't setup, and you'll have a mess.