After I cut off the front rail and the tail light brackets, I removed the plywood decking and flipped the trailer over. The bottom was skinned with 1/4 inch marine plywood.
The bottom skin is attached with machine screws and seams sealed. The leveling jacks are attached to the steel frame at both ends with machine screws. The bottom was then painted with black marine underside paint that has fiberglass strands in it.
Frame is flipped back over and ready to insulate. (Better insulate than never)
Each bay of the framing is insulated. First, Ecofoil is fitted and taped in, followed by a fitted piece of rigid foam.
Every bay of the frame has been fitted with Ecofoil and rigid foam.
The trailer’s plywood decking is reinstalled over the insulation. It was dirty and rough, but it would all be covered up.