Condensation

[bneukam]

nothermark,
Don't take this the wrong way, as you are totally correct with what your saying.
If you put out a glass of ice water, the warm air around it is drawn to it, then condenses on its cold surface. The warmer the air is around it the more condensation you have, because the draw is greater.
Moisture traps are created by having an air space between two vapor barriers. By installing foam board tight against the outside walls you will make that space warmer. Therefore less draw.
Built several homes in cold climates. We use thick plastic on the inside walls. If you have an area that is weaker in its resistance you will have a greater draw to it.





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[Mr_D]

Originally Posted by CC Driver

Condensation comes from the usual sources such as showering, cooking, making coffee, etc. Also, a big contributor is just breathing. With Country Coaches being well built and sealed, you must open a vent or window to get rid of extra moisture. Our fan in the bathroom never gets closed. We also have the bedroom cabinets over the bed and learned early on that 1) you cannot pack them tight in the winter, and 2) they require air movement during the day. We will reduce the amount of "stuff" in those cabinets for the winter and also leave them open during the day to circulate the air.

Currently wintering in PA.

I tried leaving the cabinet doors open but our cats fill them up!

[CC Driver]

Originally Posted by Mr_D

I tried leaving the cabinet doors open but our cats fill them up!

So........heat by cat?

[nothermark]

Originally Posted by bneukam

nothermark,
Don't take this the wrong way, as you are totally correct with what your saying.
If you put out a glass of ice water, the warm air around it is drawn to it, then condenses on its cold surface. The warmer the air is around it the more condensation you have, because the draw is greater.
Moisture traps are created by having an air space between two vapor barriers. By installing foam board tight against the outside walls you will make that space warmer. Therefore less draw.
Built several homes in cold climates. We use thick plastic on the inside walls. If you have an area that is weaker in its resistance you will have a greater draw to it.

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Totally agree. What I worry about and is worth pointing out here is putting insulation in with an air gap so air gets behind it, condenses out to water that feeds mold when things warm up. Either glue in the insulation or remove and inspect on a regular basis.

[bneukam]

You could cut the foam board 1/8 inch larger than the gap you want to fill. This should give you a tight fit. Before putting in place wrap the foam bard with a small strap, with the ends facing you. That way you can inspect after install, by just pulling it out. I would also leave the doors slightly open.
Knowing what your relative humidity inside the coach is very important. 30% for temps above 40 degrees is a good start. Then as temps drop, you should also lower the humidity inside. This may require to lower the temp inside to better achieve this. Moisture inside walls is never a good thing especially if a good freeze follows. Personally for this reason alone I would never live in a hung wall construction. Batt insulation when damp can drastically lower its effectiveness.
That brings up a question, is the tubular steel on our coaches filled with spray foam, or are they empty voids?


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[nothermark]

Properly installed batt insulation has a vapor barrier on the inside and is vented somewhat on the outside so should not be picking up any moisture.

Batt can sag an inch or so at the top unless overstuffed. Foam can be poorly sprayed. Both work when done well, both can be screwed up. We pay our money and take our chances.

[CountryFit]

last winter we ran into the issue of condensation on windshield and windows every morning so we bought a 25-pint frigidaire dehumidifier. it took about a gallon of water from air in an hour; unbelieveable. that took care of it pretty well .