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Kpendy 02-08-2017 10:59 AM

Condensation arghhhh
 
Ok guys I hate to do this but after searching for like 15 minutes I can't find anything that applies.

I have insulated the bananas out of my bus, r13 on top of original fiberglass on the walls all the way down under the windows, spray foam all the way down on the upper walls where windows were removed and on front and back, r25 on whole floor and even steps, and don't remember r value of rigid foam board on top of original fiberglass on ceiling.

So now that my bus stays nice and toasty I kick on my salamander heater for 3 minutes and I'm good for 30-45 minutes in 15 degree weather

When it gets warm in there now it condensates the windows all up and if I'm hearing in there for a whole day i will start to see it's bit on the ceiling ribs that the ceiling panels are screwed to.

Only thing I found about this was that houses do venting though the attic and we don't have an attic hahaha so how should I vent the ceiling?

I feel if I put a fan up there it will suck all of the heat out of the bus in the winter(because heat rises duh) but don't think that would be an issue for hot weather more of an advantage.

So I guess question is do I cut a couple holes spaced out on the roof to the interior and just put free flowing caps on them to stop water from getting in or should I put a fan in a hole in the ceiling? Either way not an issue I can do anything with it just wanna hear some advice from some ppl who have trial an error done this haha

Please and thank you thank you thank you

Sundowner 02-08-2017 12:02 PM

If it is on propane you will get lots of moisture

Kpendy 02-08-2017 12:22 PM

Well the salamander runs diesel but my permanent heating will be propane. I just need to know what the best option for venting is to keep it to a minimum.

Sundowner 02-08-2017 12:32 PM

I use a dehumidifier during the winter and that makes a big difference with the moisture problems

family wagon 02-08-2017 01:15 PM

Any kind of combustion yields water vapor; it doesn't matter whether the fuel is diesel, kerosene, propane, wood, etc.

Condensation happens when air comes into contact with a surface temperature below the dew point. Dew point and relative humidity are intimately connected.

Operation of an unvented heater inside the bus adds water vapor to the air, ie drives the relative humidity way up. That drives the dew point up. Condensation results. It'll even happen in the summer (think of a steamy shower) but it'll happen even faster in the winter.

It sounds like you may need a combination of humidity control (use a furnace-style heater or vent the combustion gases outside) and vapor barrier (keep vapor-laden air from passing through permeable insulation and condensing in or behind the insulation, wherever temperature and dew point cross).

Versatile 02-08-2017 01:48 PM

Leave a window open a bit.

Kpendy 02-08-2017 01:53 PM

I was thinking I'd have to do that, and honestly I like this option MUCHHHH more than cutting holes in anything lol plus I can skip wiring a fan up and just use an outlet for the dehumidifier.

Good thing is that thing is pretty darn airtight. I need to post some more pics

DoubleO7 02-08-2017 02:00 PM

I would never run a diesel fueled salamander heater in a confined space.
Carbon monoxide poisoning kills you.

Kpendy 02-08-2017 02:12 PM

Hahaha I leave the door open and a couple windows while it's runnin and close em a bit after I turn it off but diesels really not too bad it's like 1-10% emissions of gasoline depending on efficiency of the burn so a few minutes isn't guna kill ya but I hear ya for sure fumes in a closed space is not a good idea.

Deezl Smoke 02-08-2017 02:21 PM

Quote:

Originally Posted by Kpendy (Post 184246)
Ok guys I hate to do this but after searching for like 15 minutes I can't find anything that applies.

I have insulated the bananas out of my bus, r13 on top of original fiberglass on the walls all the way down under the windows, spray foam all the way down on the upper walls where windows were removed and on front and back, r25 on whole floor and even steps, and don't remember r value of rigid foam board on top of original fiberglass on ceiling.

So now that my bus stays nice and toasty I kick on my salamander heater for 3 minutes and I'm good for 30-45 minutes in 15 degree weather

When it gets warm in there now it condensates the windows all up and if I'm hearing in there for a whole day i will start to see it's bit on the ceiling ribs that the ceiling panels are screwed to.

Only thing I found about this was that houses do venting though the attic and we don't have an attic hahaha so how should I vent the ceiling?

I feel if I put a fan up there it will suck all of the heat out of the bus in the winter(because heat rises duh) but don't think that would be an issue for hot weather more of an advantage.

So I guess question is do I cut a couple holes spaced out on the roof to the interior and just put free flowing caps on them to stop water from getting in or should I put a fan in a hole in the ceiling? Either way not an issue I can do anything with it just wanna hear some advice from some ppl who have trial an error done this haha

Please and thank you thank you thank you

If it is cold outside, like below freezing, take a piece of heavy metal outside and let it get cold. Something like a lifting weight or equipment. Then take it into a warm room right away. What happens? Beads of water will collect on it and start running off until the metal warms back up enough.

This is what is happening to your bus. The windows are cold and the air inside is warm. There's a reason they call it "condensation". The warm air molecules "condense" or get smaller near the cold surfaces. As they condense and get smaller, they can not hold as much water in them. So the water is forced out.


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