Condensation on interior of bus

rossfree · 12-10-2016, 08:43 AM

Hi all,

Can anyone comment on condensation. I'm in the middle of my conversion and I'm curious. i have a small bus... 6 window. I am not removing the ceiling sheet metal skin. I did remove the interior walls and re-insulated and put in bead-board walls. The floor will be minimally insulated with 1/2" polyfoam, 1/2" plywood and hardwood on top of that. But I am curious. When showering or cooking, is there ever much of a problem with condensation during cool or cold weather... condensation dripping or running down the ceiling or walls?

Thank you,

Ross

Tango · 12-10-2016, 08:57 AM

I'll let others chip in on this but my personal experience was that the majority of condensation (as in " indoor rain") came from relying on propane heat. Maybe one of the scientists here can elaborate on the "why".

Deezl Smoke · 12-10-2016, 09:27 AM

Straight up, pure and simple. Condensation occurs when warm MOIST air comes into contact with a cold or cooler surface.

So,....just you being in the bus, breathing, will put moisture into the air, as well as some heat. Warm air can hold more moisture than cool air. When the warm moist air comes near or into contact with the cold surface of your bus ceiling, it will condense. When it does so, the moisture is pushed out of the air and returns to liquid form again.

There are tons of applicable videos on youtube explaining it, and many of them do so very well.

Phatman · 12-10-2016, 10:08 AM

Quote:

Originally Posted by rossfree

Hi all,

Can anyone comment on condensation. I'm in the middle of my conversion and I'm curious. i have a small bus... 6 window. I am not removing the ceiling sheet metal skin. I did remove the interior walls and re-insulated and put in bead-board walls. The floor will be minimally insulated with 1/2" polyfoam, 1/2" plywood and hardwood on top of that. But I am curious. When showering or cooking, is there ever much of a problem with condensation during cool or cold weather... condensation dripping or running down the ceiling or walls?

Thank you,

Ross

You should really consider using 3/4" of plywood for a couple of reasons.
1. It is a more stable base. consider what will happen if you screw anything to the floor. 1/2" is not thick enough to have many of the threads of the screws imbedded into the wood. (use sheet metal screws instead wood screws. The threads are bigger on sheet metal screws.)
2. 1/2" plywood is just too mushy plus the cost of superior 1/2, you might as well purchase 3/4".

Scooternj · 12-10-2016, 11:09 AM

I would seriously consider reinsulating and replacing the ceiling. That's going to be one of the biggest heat sinks on the bus. So all the warm, moist air that you're generating, especially in winter- breathing, propane heat, showers, cooking, etc., will rise up, interact with the cooler air being generated by the thermal bridging from the metal ceiling, and create your indoor rain.

Deezl Smoke · 12-10-2016, 02:00 PM

Quote:

Originally Posted by Scooternj

I would seriously consider reinsulating and replacing the ceiling. That's going to be one of the biggest heat sinks on the bus. So all the warm, moist air that you're generating, especially in winter- breathing, propane heat, showers, cooking, etc., will rise up, interact with the cooler air being generated by the thermal bridging from the metal ceiling, and create your indoor rain.

Looking for the LIKE button. This will have to do.

milkmania · 12-10-2016, 02:03 PM

What effect would a dehumidifier have?
I don't have condensation problems, as I'm alternating electric heat (primary) and propane heat (secondary)

But, I've got a portable A/C (110v floor model) that's got a dehumidifier setting and it'd be super simple to plumb a slobber tube through the floor, as opposed to pulling the plug and draining the tank.

milkmania · 12-10-2016, 02:06 PM

Quote:

Originally Posted by Deezl Smoke

Looking for the LIKE button. This will have to do.

AlleyCat67 · 12-10-2016, 02:11 PM

One LIKE button.....

superdave · 12-10-2016, 06:16 PM

Quote:

Originally Posted by milkmania

What effect would a dehumidifier have?
I don't have condensation problems, as I'm alternating electric heat (primary) and propane heat (secondary)

But, I've got a portable A/C (110v floor model) that's got a dehumidifier setting and it'd be super simple to plumb a slobber tube through the floor, as opposed to pulling the plug and draining the tank.

something to think about, i had 3 electric heaters going in my bus with half the bus blocked off in single digits. it was 37* in the bus in the mornings. nothing i did would overcome that steel ceiling and single pane windows, my dogs are still pissed.

joeblack5 · 12-10-2016, 07:02 PM

It is a lot of work to remove the inner skin unless it is screwed.
The inner skin adds a lot of structural strength.
Unless you go thru a lot of extra trouble of making a proper insulation space between the inner frame and the ceiling material you will still get condensation on the roof ribs.
A metal ceiling does not burn easily, wood does.
foam gives very,,, very nasty toxic fumes when it is burning.

Don,t take me wrong I believe in foam and some of the positive effects.
My solar panels are 2" above the roof and I think using 1" isulation sheet on top of the bus between the solar panels and the outer skin re solves all of the problems in one go.

Good luck J

milkmania · 12-10-2016, 07:51 PM

Quote:

Originally Posted by superdave

something to think about, i had 3 electric heaters going in my bus with half the bus blocked off in single digits. it was 37* in the bus in the mornings. nothing i did would overcome that steel ceiling and single pane windows, my dogs are still pissed.

The vent free propane stove is behind the driver's seat, secured to top of countertop... I won't ever sleep with it running, I've got 1 milk house heater on top of refrigerator near the ceiling (metal on metal on metal!!!) That one has a contact switch, so if it somehow comes off the fridge... It'll shut off.

Then in the bedroom, I've got 2 milk house heaters suspended from the ceiling (again metal on metal on metal! They have what I assume are Mercury type switches, so they don't have to sit on something. One is on remote control and one is not. Both are mounted with heavy duty binder clips to metal straps.
I only had to use the second heater the other night when temps dipped to 18°.
If one of those comes down, they're going to switch off... Plus make a helluva noise!

Also, if it gets too cold... I can close the bedroom sliding doors.

milkmania · 12-10-2016, 08:11 PM

iPhones name all their pictures "image" and the board sees the same name and won't upload more than a couple... I'll try this

AlleyCat67 · 12-10-2016, 08:14 PM

I'm presuming this is what you are calling a "milkhouse heater"??

Don't want to look or sound dumb here but I'd never heard that term before until you started using it whenever it was in the last couple of weeks or so....

Deezl Smoke · 12-10-2016, 08:33 PM

Quote:

Originally Posted by milkmania

What effect would a dehumidifier have?
I don't have condensation problems, as I'm alternating electric heat (primary) and propane heat (secondary)

But, I've got a portable A/C (110v floor model) that's got a dehumidifier setting and it'd be super simple to plumb a slobber tube through the floor, as opposed to pulling the plug and draining the tank.

Anything to reduce the humidity will help somewhat. However, usually a device like that can not keep up with the addition of moisture having someone living inside the bus and thru normal living duties such as cooking, showering, and washing tings, there will be more moisture added than can be removed.

The dehumidifier is a perfect example of the workings of condensation. You'll notice the cold side of the mechanism ices over, then melts the ice off to dispose of as water. Same thing as a car in the summer, where you always see a puddle of water under it if the AC was running. Having warm, moist air running across a cold surface.

I can not give advice as I am in no way in such capacity. However, I can tell you a story of my stick built house that applies here somewhat.
My non insulated house had natural gas furnace heat. For may years my books would warp and windows would sweat and mildew. It was a lot of work to keep the windows clean to avoid possible health issues. I had a stand alone dehumidifier in the central hallway and it would run 24/7 all winter long. Still, wet windows and 70+ % humidity. And that was even with just myself and a dog in the house for evening and night. No one here in the day.

Well, I finally had enough and asked the owner to buy pellet heat. Instantly, the windows are dry and the books are dry and straight. Humidity is in the 40s. I can wash and shower in hot, steamy water now and cook all I want with no issues whatsoever.
What was happening was the gas furnace was on a thermostat that would run the furnace for a period to get the air temp up to it's set limit, then turn it off until the temp dropped just so far, then repeat. Well this cycling of the heat and the furnace being a closed circuit with the intake inside the house and the ducting enclosed, the house and the items inside could never get up to temp before the furnace would shut off. Only the air got up to temp to cycle the thermostat. Now with the pellet heat, I opted to draw the combustion air from inside the house and have a air inlet from a warmer area. The pellet stoves are set on manual and run constant. This allows all of the items inside the house as well as the walls to come up to temp and act as a mass heat sink. No more sweating windows or high humidity.

milkmania · 12-10-2016, 08:40 PM

Quote:

Originally Posted by AlleyCat67

I'm presuming this is what you are calling a "milkhouse heater"??

Don't want to look or sound dumb here but I'd never heard that term before until you started using it whenever it was in the last couple of weeks or so....

Im sorry, but yes this is a milk house heater....age old design
Also use them in well pump houses.
The possibilities are endless

What is a Milk House Heater?

AlleyCat67 · 12-10-2016, 08:45 PM

Okay thanks for that..... I've seen them before, just had never heard them called that.

milkmania · 12-10-2016, 08:52 PM

Quote:

Originally Posted by AlleyCat67

Okay thanks for that..... I've seen them before, just had never heard them called that.

Ah, ok.

Grew up around cows, then started pasteurizing milk for a large bottling company... So I was always around them, even before Walmart hit the big time

AlleyCat67 · 12-10-2016, 08:55 PM

Makes sense that you would know that then..... I unfortunately have been a city boy all my life.... I hate city living, would much rather be out in the country. Not that city life is ALL bad, it's nice having everything you need close by, but TOO MANY PEOPLE. I'd rather live in a town where you could put the entire population of the town inside a Walmart and it would still not be crowded.

milkmania · 12-10-2016, 09:38 PM

Quote:

Originally Posted by AlleyCat67

Makes sense that you would know that then..... I unfortunately have been a city boy all my life.... I hate city living, would much rather be out in the country. Not that city life is ALL bad, it's nice having everything you need close by, but TOO MANY PEOPLE. I'd rather live in a town where you could put the entire population of the town inside a Walmart and it would still not be crowded.

Country life has its ups & downs for sure. Came from Los Angeles area when I was about 7, so I don't know much else.

You should see walmart on Friday night before Saturday's opening of deer season..... They all look like glassy eyed slobbering zombies pushing shopping carts! lol

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