We got six exterior grade BC plywood boards to replace the current sub-floor in the Airstream. Dan traced the old boards for the right size and shape except for the very rear one, which he guessed since the original was super rotted. We also picked up some expoy to coat the boards and make them watertight. This way, should any water get down to the sub-floor, it will run right off the wood.
This stuff was cool. It came in two cans, and when mixed, you have about 12 minutes until the chemicals set. Dan had to switch out the rollers about every 20 minutes. Once it dried, the boards had this glass-like coating.
Just a few more pieces to get in place, and then we'll start re-assembling!