Condensation questions

[kd5edj63]

I did some searching and cant find good solid assurance on my issue, which Im sure is a common issue.
I slept in the camper last night to test the adequacy of my heater buddy since its been cold lately. Lots of condensation, but only on the walls and doors which are 3-4" birch plywood with a spar varnish (2 coats, no sanding between coats, except on the doors. The doors are extremely smooth)
Is this something I need to worry about. Can I simply wipe the walls down, getting most of it off and let it air out. Its humid as hell so Im sure it wont air out in this weather. Is there a way to prevent it in the 1st place. Cloth layers, dehumidifier, extra ventilation.... How will the spar varnish hold up. Any help is appreciated

[kd5edj63]

Im wondering if a couple of these might do the trick great reviews
http://www.amazon.com/Eva-dry-Renewable ... ewpoints=1

[madjack]

PROPER VENTILATION...that's the key...coldest I have camped in was in the lower 20's, with two people, two mutant chihuahuas and a very small ceramic heater...kept roof vent and windows open around an inch with the heater set on one...no condensate issues other than a little sheen on the uninsulated roof(no ceiling)...once we got up and out, leaving the heater and windows/vent as set, that all went away........
madjack

p.s. NEVER sleep in a completely closed up teardrop as you may wake up dead...not a god thing!!!!!!!!!!!!!!

[kd5edj63]

I left a window cracked just a bit. Not enough to kill the heat. Might get 2 of the dehumidifiers

[tony.latham]

My 4x10 Hunter has 1/2" plywood walls and almost always got condensation unless the window were cracked at least a half inch. I recall some hoar frost one 11ºF morning. This photo shows it at about 30ºF:


My new home-built with the 1" walls and 3/4" of insulation doesn't get condensation on the walls that I've seen yet, but I still get the moisture on the Frank Bear glass doors (that I really like). Either way, you really need to ventilate your teardrop to stay alive. I'm not convinced varnish seals the wood completely, but my interior has three coats of poly and crossed fingers. I never did get any water damage in the Hunter. When it got really damp, we wiped the walls down with towels.

But spend $16 on that gizmo, take it on a shakedown cruise and get back to us!

Tony

[working on it]

from the thread Air Tight Teardrops can KILL YOU

Parnold said :As far as air tight goes, my trailer is encased in polyester resin. The floor is encased in rubberized undercoat. All my doors and windows have factory rubber seals (I did not build a single one) so it is pretty darn airtight. You can definitely feel resistance when closing the door if the windows are closed.

working on it said: My trailer is sealed tight also, with extremely tight fit around the doors (67-72 Chevy truck seals), and must be forced shut. The inside is sealed with paint, the exterior with poly and paint. All seams are sealed with PL adhesive. I have tight butterfly covers on the cabin vents, and the windows seem to shut very tightly. I experimented with the A/C and electrical system a while back, and found out, among other things, that the trailer is too well sealed. In a matter of just 10-15 minutes, with no external airflow or A/C running, the humidity inside would rise from comfortable to miserable (48% to 99%). I guess that there was a considerable CO2 build-up also. And that's with just one person in the 4x8. I guess that I must leave vent cracked open at all time to avoid this, since the little A/C has no "fresh air" feature.

If your trailer is as airtight as mine or others, the humidity in the air, and moisture in your breathing will collect if there's no way out of the cabin. And if the moisture can't exit, then neither can fresh air enter. Like madjack said, leave a vent or window open for both purposes. PS: condensation forms on the exterior also. When camping in September it was very humid. I set a coupla trays of food for the gathering that evening on my mattress, turned the A/C way down to keep them cool (no vents or windows opened), and left for a few hours. When I went to fetch the trays of food, they were quite chilled, and the exterior walls of the trailer were cold and wet. Condensation. Showed me that I needed some insulation after all, so I will add some before my next trip.

[kd5edj63]

Thanks guys. I'll get a couple of those dehumidifiers. In the warmer climate when I can run the vent fan for a good while with windows open I'm sure it will be less of an issue.
Love the pic Tony. Thanks for sharing. (and your input)

[kd5edj63]

Just ordered 2 dehumidifiers and a new power inverter. The inverter I had was in bad shape, awkward and only 100 watts. Got a much better one for less than a $25 dollar bill

[Junkboy999]

I cant remember what the magic number is, but Condensation forms if there is moisture present and if the temperature is more the a (15 S.W.A.G.) 15 deg difference on one side of a surface compared to the other side. If you have a one piece wall ( one layer ) you will easily get a big difference in temperature from the outside to the inside. This will cause the condensation. As stated above, it can form on the outside as well if the moisture content of the air is right and the internal temp is right.


If you have multiply layer in your wall, each layer will be at a different temperature then the layer next to it. This cuts down that chance that there will be a big difference from one layer to another. In Tony case above his wall with insulation, outside sheathing, and probably an inside sheathing does not get the condensation but his one layer glass window / door does.

If you keep is wiped off every morning and let it air out it will be ok. The problem come into play when you not using your camper and it is in storage. If sealed up tight and it goes through a lot of temperature changes it can build up moisture and can rot and grow mold if you do not attend to it. You can buy tubs of moisture collecting gel, pellets or crystals. to place in the camper when not in use. They will need to be emptied every month or so. We use them in Germany because of the condensation problem most of their solid brick houses have.

[kd5edj63]

Thanks. I noticed my insulated roof and front and back walls etc didnt get condensation. Just the solid walls. Im not worried about the outside. It should be as good as a house if not better

[Westcliffe01]

You need a vented heater. The buddy heaters are not vented. Anytime you burn anything (including hydrogen) water is a byproduct in the form of steam. What you were seeing is the combination of steam from the buddy heater + the vapor in your own breath. The more fuel you burn, the more water vapor. (Look at the vent of a NG furnace when it is cold out, you will see the steam).

If you use a vented heater that dumps the combustion products (including CO2 and CO) outside, then it is possible to raise the temperature of the inner wall surface past the point that anything would condense on it. Then even your own vapor from your breath will not condense on the wall of the trailer. But the other poster was also right, you need to ventilate, since your breathing would add more and more water vapor until you would reach dew point (fog).

When mounting a vented heater, always put it as low as feasible since heated air rises and you want to set up a convection loop to spread the heat around. Also be sure that the burner has a source of outside air for combustion so you are not creating a draft through every crack in the trailer of cold outside air.

[MtnDon]

25 ounces of water from every gallon of propane burned.

[kd5edj63]

Thanks guys, I'll check into a vented heater. But in TX I dont think much heat is needed most of the year.

***Edit. I dont see much in a small vented heater. Actually nothing in a small vented heater. I could use a link to an example of a tear friendly vented heater.

[Westcliffe01]

This is the most popular style heater. It will need a thermostat, 12V + propane to work. With a 16k btu output, it will not take long to raise the temp.. For a small trailer, it would run intermittently until it bumped up against the thermostat. A single solar panel to keep the battery topped up would probably suffice in a situation where there was no access to 120V. It draws 2.8A while running but that may only be 10% of the time. One of the keys is to have a thermostat that has a wide "dead zone" to allow the temperature to rise sufficiently when the heater is on and drop sufficiently while it is off. The battery powered electronic ones allow all these parameters to be adjusted so that the heater is not running every half an hour for 5 min...

http://www.ducktec.com/itm00098.htm

[kd5edj63]

Thats way too expensive for something I might use a few times a year. Thanks anyway. I'll find a cheaper solution