The strapping panels run the length of the bus so they are perpendicular to the metal strips you see.
The metal strips are screwed into the strapping panels. They provide additional support for the plastic sheeting and afford a nice trim cover for each 4'x8' plastic sheet
The sheets themselves have plastic rivets installed into the strapping panels every 16 inches or so.
The strapping panels are screwed into the steel bus ribs.
This way there is no highly thermal conduction path between the outside skin and the inside.
Before the plastic panels were in place I took time to foam tape insulate every screw head that attached the strapping to the steel body ribs.
In the winter time, each screw head would form a drip of condensation without the foam tape.
Originally Posted by RHOMBUS
family wagon: My thinking on the inside metal is that it would be cooled much faster than the surrounding air due to conduction from the exterior passing through all of the screws. In the summer, the metal ceiling would be like a mild heating element, and in the winter, a mild freezing element. The ribs would for sure with no real way to prevent it, so anything attached to the ribs would be an extension of that effect. I could be wrong, or possibly overestimating the effect, but it seems to logically follow. I've seen videos of thermal bridging in homes through the 2x4 framing and am just imagining how much more of an issue it would be with metal.
The FRP looks pretty interesting and I will check that out.
aaronsb: Are the strapping panels the metal strips I see between the white ceiling panels? If so, do the plastic panels then slip under them similar to a dropped ceiling? I really like the look.
I do plan on active ventilation and will not be using any propane systems at all in an effort to keep excess humidity to minimum. The bathroom area will be as completely sealed off from the rest of the bus as I can make it.