Originally Posted by HolyBus
... What is that little round vent thing in the ceiling between the steps and the driver's seat? I found a small puddle on the floor under it this morning... The ceiling is damp all over.
The round thingy is a passive vent. I ended up shooting a bit of Elastomeric sealant and placing a bit of flashing in the opening to seal the outside and placing a piece of sheet metal cut to fit behind the metal screen (which I cleaned and painted with spray paint as it looked bad). We found we were losing too much of our air conditioning out it (it's directly above the vent of the A/C unit).
As for your ceiling, we had that problem before the bus windows were pulled and rebuilt (only when it rained otherwise too dry in NM for condensation). Once we got things more finished (insulated and the exhaust vent on the range), the ceiling stopped condensating. Except in the bathroom when I take super hot showers. Cracking the window a tiny bit allows the moisture out without letting out all my lovely heat. Turning on the vent over the range hood sucks everything out in a matter of minutes (like about 5-10 minutes) I do need to install some solar powered fan-forced deck vents in the ceiling (on/off switched kind). Particularly in the bathroom hallway (for the shower moisture), the rear bedroom and the salon (to pull hot air off the ceiling in the summer so I don't have to run the A/C).