If you ever have owned a house, you know that every once in a while you need to caulk around the windows and doors, well the RV is even more important. Imagine as your driving down the road the window and door frames rubbing and shaking as you hit the bumps and dips in the road. Even while sitting still at the campground the stress that is put on them when leveling the rig. This movement is normal, but over time it breaks the seal that was installed when the RV was build that prevents water leaking into the RV. These water leaks may be very evident with wet wall or floors, but it may also be hidden behind the walls.
Caulking is a task that you want to schedule about every 4 years or so. You will need a couple of days of clear, dry weather to allow the caulking to cure. This is a simple process and will only take a few hours to do. You will need a ladder, caulking and some clean rags. Which caulk is the best? I don’t know, but since it is exposed to the weather, I would get a good outdoor caulking. I prefer one that dries clear.
Caulk around the whole frame of each window and door. If you have a drivable RV you will not need to do the front window as they are sealed with a rubber grommet. However, if you have an older rig that has some rust around the windows, it won’t hurt to seal that area as well.
I think caulking is an art. The more you do the better your seals will look, so practice makes perfect. Best of luck and hopefully we will met on the road.