caulking a class c

I use NuFlex #313 fast cure glass & vinyl white silicone. Don't worry about it saying glass and vinyl. It's fine for sealing seams on the RV etc... For the roof, depending on your roof material, dicor self leveling etc....

Eternabond - takes a bit more work on the front end but it's pretty much bullet proof after instal.

I use Sikaflex myself. I'd do a blower door test first to see where it's leaking before redoing everything.

I use Duralink 50 which stay 50% pliable for life. Really takes the vibration from an RV on the road. Comes in many colors. Repaired the side of my RV after a tractor trailer hit the corner and has held up for many years. Also, on seams, I'd also use Eternalbond tape.

I've been using Eternabond where possible and for caulking I use proflex. It works pretty well.

For long or straight seams, Eternabond has been an almost-permanent fix and if you buy a decent roller and a nice razor knife it's really fairly easy to apply.

Lexel specs, works on just about anything.

What worked for me was scraping off the old caulking on the joint of plastic front on the cabover to the metal roof, carefully sealing it with new RV caulking, then putting a strip of 4 inch Eternabond over top. You need a small roller to apply Eternabond.

My husband tackled this project last June and we are very happy with the results. After much research, he used seal-tite corner seal (only available on line and high shipping and handling, but great stuff) http://www.sealdesignllc.com/catalog/seal-tite-corner-seal/ and sikaflex 1a (both before and after using the seal-tite corner seal, which is like a sticky tape).
The most time consuming part was cleaning up the trim. We reused the vinyl insert because it was in good condition and we couldn't find anything as heavy duty as the original.

I also did the sealtite tape. Its defintely a job to do it right but will outlast the life of the rv. Its finally out on amazon and other places just recently.

Also used sikaflex for secondary seal.

Never ever ever use silicone on an rv for any reason it has zero bonding capability. Sika is polyurethane same as whats used in car windshields to bond watertight to the vehicle and will last indefintely

Yep . Sikaflex or other quality urethane. Other stuff doesn't hold up.