Originally Posted by jking
Our '84 310 has the freshwater tank and water pump located under one of the twin beds in the back. Our old 280 had it under the couch. Both had condensation moisture and dampness, which promotes mildew and smells bad. We have removed everything, thoroughly disinfected, and sealed all surfaces with shellac. Now we are determined to prevent reoccurance, and any suggestions would be welcomed.
Generally, good ventilation is the general answer to controlling condensation, and minimizing the opportunity for mold. Always, use the exhaust fans in the shower, toilet and kitchen. And crack a window open to let air get into the trailer. If its cold outside use the heater to keep the inside temperature from getting too cold.
If its hot outside run the AC unit, since it will dehumidify the air inside the trailer. I suggest to still use the exhaust fan in the shower, when showering, and in the kitchen, when cooking (still cracking a window), and running the AC unit.
However, if you are talking about what to do in a stored Airstream, say in a place like Florida in the summer, the answer is dehumdification. The air inside a stored trailer will be dehumidified by running the trailer's air conditioner. Using a chemical desiccant may work, but personally I like the idea of using the AC unit, coupled with timely inspections. There is a forum that has a great posting detailing using a chemical dessiccant.
Remember, in the summer when its hot outside, even the smallest opening or crack, will allow moisture to enter the trailer. In fact, it is forced in since the vapor pressure is higher outside, where its hot, versus inside, where its cool. That's why most houses have vapor barriers. You will notice that with houses vapor barriers are always installed on the warm side of the exterior wall. (In cold climates thats on the inside of the exterior wall's insulation, and in warm climates its on the outside of the exterior wall's insulation.)
If the shellac was used on the inside of the exterior wall it will not be nearly as effective as a good use of caulk, and tight joints on the outside.
The obvious complication for us Airstream owners is that we move our trailers from climate to climate. However, good ventilation remains the answer, but whether you use the heater, or AC unit depends more on where you happen to be parked.