7sparky7,
Thanks for the kind words. About everything I have done to my trailer so far has been borrowed from other people’s ideas posted on this web site.
By installing an additional 1 3/4 inches of insulation on both walls, I lost 3 1/2 inches of interior width. Consequently, now I cannot load two bagger motorcycles side by side as I originally planned. However, I think the tradeoff is worth it in my case.
Here is a link to a series of posts where the topic of insulation under the floor has been discussed (there are probably more posts but this post came to mind).
viewtopic.php?f=42&t=69445&p=1217306&hilit=mice#p1217306 If I were to insulate under the floor, I think I would go the do it yourself spray route, even though spray foam is a bit expensive. However, I suspect that the savings in labor plus higher R value due to an airtight application would more than offset the extra cost. Also, I would think that the spray foam would adhere more securely over time compared to the risk that cut and glued panels might eventually come loose. As far as exterior paneling to cover the foam, I would start by looking at the plastic like material that RV manufacturer’s use under their floors. I would also consider first painting over the foam with the kind of thick stuff that the teardrop builders apply to the underside of their wooden floors to make them water proof, then apply the paneling.
In any event, good luck with your build and keep us posted ... photos are always appreciated by everyone!