Originally Posted by JackE
The amount of rust on those framing pieces indicates a lot of moisture getting places it shouldn't. I would be willing to bet you have some roof seam leaking going on. The motor home I am tearing apart as donor for my bus looks like this in all the walls. It had/has serious roof leaking issues. You need to find and fix all the leaks before you start any inside work or it will soon be ruined too.
Yes, you're right. I saw a break in the middle seam that runs along the top of the bus. I ordered some tropicool roof sealant yesterday and I'm about to pick it up now after sealing the seams.Hopefully that'll do the job.