28 ft silverton 1976 I always seem to mildew on ceilings.when I am done boat in the winter all bunks come out.I have a small fan on a timer on 6 hours off 3 hours.it makes a big difference. But still some mildew .I cleanin mildew cleaner from home dept. Comes clean fan runs in sumer too.after I clean it is there something I could on to keep it off? Also have to clean at least once thanks for any help bcclew.