Sealants can make or break your RV! The term “sealant” includes various types of caulk, putty, and tapes on the body that are used to seal seams or where two components come together. Sealants are there to keep the water out. Sealants are even used where screws attach things to the roof or outside walls, because rain water, dew and the condensation water draining from the rooftop air conditioner will follow the screw threads into the wood. Any exposed screw heads or rivets on the roof or outside walls need to be covered with sealant. If you install anything on the outside roof or walls with screws, you should apply sealant to the threads of the screws before you install them, and then cover the heads with sealant.
The wood that RVs are made of is selected for light weight in relation to strength, and for low cost. The lumber, plywood and particle board usually have very little resistance to rot from water, so it is incredibly important to keep water away from these wood products unless you want to have a huge repair bill. The roof is the most obvious place where all the seams and attachments must be sealed, but the windows are another major source of water getting into the walls. The windows in RVs are usually installed with a strip of gummy tape or putty between the window frame and the outside wall. The tape shrinks and gets hard with age, so water can leak into the walls and rot the panel and structure, and cause delamination of the outer siding before you realize that it was leaking. A good prevention is to apply a bead of caulk around the outdoor perimeter of each window frame to seal it to the outside wall.
On the roof, there are so many places where water can get in, such as the base for the refrigerator vent, plumbing vents, crank-up vents, skylights, radio antenna, ladder mounts, TV antenna and satellite dish system. These are mostly flimsy plastic components that are secured with screws. At least every 6-months, someone needs to go up on the roof to inspect to make sure that these plastic items have not been broken by a tree limb, cracked from exposure to the sun, and or other damage. The inspection needs to include looking for any cracking or peeling of the sealant around these devices and their screws, and at seams where the front and rear roof caps meet the roof. If more sealant needs to be overlaid, or if the old sealant needs to be scraped off and replaced, be sure to use the correct sealant for the material that you are applying it to. Your RV dealer’s parts department can help you select the correct products. DO NOT use sealants from a building supplies store, the sealants for RVs are designed specifically for the materials which they must adhere to, exposure to direct sun, expansion and contraction, and movement from driving.