Humidity and ventilation

[asquarecan]

Hey guys!


So I had a conversation yesterday with someone that got me thinking. Not having an experience with RV's or trailers I did not think too much about this.



If I spray foam the bus am I doing to have to worry about humidity/moisture inside the bus?


Also are you guys running an exhaust fan of some sort to keep moisture or humidity down?


Thank you as always!

 

[PNW_Steve]

It depends on climate and how much moisture you add to the environment.

I have lived in a bus with spray foam insulation in the Seattle area in the Winter.. FWIW in a 5th wheel trailer as well.

Just breathing adds a fair bit of moisture to the air. Showering and cooking on a propane stove a lot of moisture. When that moist air hits cold surfaces it will condense and create problems.

Living in a cold damp climate I found a dehumidifier to be a necessity.

Living in Arizona in the same bus through the winter moisture was a minor issue. Cracking a roof vent took care of it.

The spray foam insulation does not contribute to the moisture trouble.

 

[TheHubbardBus]

Regardless of insulation, or even lack thereof, you're still in a big steel tube that will not breathe with everything closed down (assuming leaks/gaps addressed). Ventilation will be required. That could be opening a couple of those big windows, exhaust fans, etc. But I don't think insulation would have much if any impact on that need. Either way nothing's getting in or out through the skin. Like Steve said, you & the environment are what determines the moisture in the air. Insulation will affect temperature, & temp will affect RH (relative humidity), but that's not really what we're talking about here.

 

[PNW_Steve]

The dehumidifier that worked best for me was a Whirlpool brand that I bought at Home Depot on sale for about #120. It had a drain hose connection that eliminated the need to dump the collected water 1-2 times daily.

 

[mmoore6856]

The dehumidifier that worked best for me was a Whirlpool brand that I bought at Home Depot on sale for about #120. It had a drain hose connection that eliminated the need to dump the collected water 1-2 times daily.

good advice from your pnw rainforest!

 

[PNW_Steve]

good advice from your pnw rainforest!

:biggrin::biggrin: I live in the desert now.

I spent a number of years N.E. of Seattle in a spot that gets quite a bit more rain than Seattle. We were in a canyon with what they called a creek in the back yard. It was one of the wettest places I have been. Once we finally got electricity, we ran the dehumidifier 24/7 about ten months of the year.

Now I live in the part of Washington that you don't hear about. Sage brush and rattlesnakes are easy to find.