Teardrops n Tiny Travel Trailers

I have a 33foot trailer. It is an older one. I took off two inside rood panel and there has been water damage. These cross members are 1 inch thich 2 and half inches wide and 7 feet long. I need to replace 8 of them. Does anyone have pictures of how to rebuild this. I would think that I would screww the new pces into the old ones for support. Pls new insullation ,and maybe a platsic sheet then the thinn panel?
Thanks for you help

I would remove the old cross members, if they are wood anyways, because any rot going on there will spred to your new ones that are screwed to them. I am facing the same thing with my old 15 footer. I haven't looked to close at it yet because I need to replace the floor first. I had thought about aluminum hat channel to replace the wood supports. Let me know what you come up with.