By Chris Dougherty
Certified RV technician
Many RVers have a silent, black, smelly enemy — mildew. Mildew is a form of mold that eats organic materials. It is a sign of moisture and water intrusion in the RV and can do a lot of damage.
Mildew spores are everywhere and require specific conditions to grow. Unfortunately, if your RV has a leak or if your RV is stored in a tropical environment, your RV is set for mildew infestation. Mildew grows ideally in temperatures between 77 and 88 degrees, with a relative humidity of 70-93 percent. Oxygen is also required for growth. While you may have some difficulty controlling the temperature of your RV while it is in storage, humidity and moisture can be controlled a couple of ways.
First, this time of year (this was written in August) many snowbirds store their RVs in the south, where they keep them for their wintertime escapes. “We’ve had more than 60 days of above-90-degree temperatures and the humidity is pretty high,” says Stu Wahl, a year-round resident of Bonita Springs, Fla., where there are a number of RV parks with seasonal sites. If power is still on in these rigs, an electric dehumidifier that is drained to the outside of the coach would be ideal for humidity control.
Alternatively, there are a number of desiccant-type dehumidifiers which will help keep the moisture level down. If you plan on using these, make sure you have enough to last the amount of time you’ll be gone. If you’re in a freezing environment, I don’t recommend using these as they can freeze. Certainly don’t leave them where, if the tub can freeze and crack, it will drain into a sink or tub drain — put it in a bigger pot that won’t be affected.
Keeping air circulating with outside (drier) air is a plus, as well, but it doesn’t work as well in the south where the outside air may be more humid. When storing an RV in the north, leave the roof vents cracked open if possible (another good reason to have vent covers.) Even if you cover your RV, have some air flow in the coach.
RV water leaks are a sure way to get mildew problems. I’ve been in RVs that you can’t even walk in because they’re so rotted and water logged — since I’m allergic to mold and mildew, I end up sick shortly thereafter! Making certain the RV has no leaks is the best way to prevent this, and that’s all about regular maintenance!
Download this PDF from the University of Florida for expert advice on how to deal with mildew.