Now is the best time to get everything built, there is good access around the trailer since the walls are not in place yet. Every project will be different depending on what is needed but I needed to add wood framing for a number of reasons:
A bottom ‘sill’ around the perimeter of the shell. For this project I don’t need to tie the corners together since I bolted each leg to my trailer but this still serves several functions. It will allow me to attach other wood framing pieces to it, it will give me something to bond the bottom of edge of the skins to, and it also defines the bottom of my doors (more on those later).
Support frames around door openings. These will just add rigidity as well as give something for screws to hold on to.
Support for wall skins. The walls are just going to be 1/4″ plywood so I don’t want it to span to far a distance without something to support it.
Places to mount accessories. I tried to lay out where all of my gear would go (water pump and system components, electrical, etc.). I would like to mount things onto a solid surface so in goes odd little pieces of wood for that purpose. This wasn’t 100% pre-planned, but it was easy to add pieces of wood where I needed them as I went along getting all of my systems built.
As I worked through this stage of the build, I was always double checking that I had the wood ‘in-plane’ with the TrailTop parts so that the skins would bond to a flat framework later on. That meant sometimes needing to notch out the wood so it would fit in flush. I used a little trim router set to depth of 1/8″ (about the thickness of the fiberglass) but you could do this a number of ways.