The two bulkheads in place with the roof. The roof is also 1/2 inch marine grade fir. I will post close up details of the frame. Its hard to tell from the photo but the uprights are a system of overlapping nailing strips and everything is glued. At this point I have not framed the side door opening. everything edge and joint is glues with titebond III and screwed with stainless or exterior grade screws. Even now, with out the skin a missing some framing, pushing on a top corner the box does not rack or even make a sound but does rock the trailer.