by cracker39 » Thu Mar 10, 2011 10:06 am
For sealing the underside of the floor, lots of folks (including myself) use the Gardner's roof coating in the green can. I put a coat of epoxy resin on the plywood first, then apply a coat of the roof coating. Finally, I stick on a 3/4" layer of Rmax foam insulation and caulk the seams for added waterproofing, but also to insulate the floor too.
For protecting the skins, prior to painting, I coat the plywood with epoxy resin and sand very lightly, just enough to smooth ouf any imperfections before priming and painting with latex floor and deck enamel. The original Squidget is 5 years old and the new owners told me a few months ago that the paint is still in good condition. The resin I use is Bondo brand from Home Depot at about $37 per gallon. One gallon will easily do a TD.