Look for Camper Dry Rot
Know what you’re looking for. Dry rot comes from fungus. It can be black or dark-colored but it can also just leave indentations in the wood (see Reference 1). Look for wood that is soft or squishy to the touch. Screws that easily pull out or that don’t stay in are often signs of dry rot underneath. Paneling that has a lot of give may also indicate a hidden camper dry rot problem.
Check the camper thoroughly for wood dry rot. An obvious place to start is the windows and doors. Look under the camper. Check around all metal trim. Examine vents and skylights. Check the hard-to-reach places such as the front exterior of the camper. If you have a fifth-wheeler, the front window in this area is especially prone to moisture damage that leads to dry rot.
Locate the Source of the Moisture
Find where the water is getting into your camper. You may have to remove some of the outer camper shell to begin your dry rot repair and find the source of the wood dry rot. Replace broken lights. Remove plastic vents and replace them with metal ones as they are less likely to crack and allow moisture into the camper walls. Reseal the roof and the metal trim with caulking.
Wash your camper. Check the bottom edges of it a couple days later. If it’s still wet, you still have a water leak (see Reference 2). Don’t begin the dry rot repair until you fix all the leaks.
Repair the Damaged Wood
Take out and replace as much bad wood as you can. (See References 3) You may have to have an expert replace structural wood or you may opt for other treatments if the wood appears to have minimal damage.
Repair existing wood with epoxy-type wood fillers. These can help rebuild the structure of the damaged wood. Follow directions and allow the epoxy ample time to dry before covering it up again with paneling or exterior sheeting.
Treat the fungal problem with boric acid. This kills the existing fungus and prevents the development of new dry rot areas.