Condensation under mattress in cold weather

[punter]

Hello all. Am staying in my motorhome for the moment and it can get cold here. Condensation is building up inside under my over-cab mattress around the outer edges beyond the cab. Has anyone had this problem and successfully thwarted it once and for all? Many thanks.

[Derek up North]

Have never had the problem, but maybe a 1" or 2" sheet of Styrofoam under your mattress and run the bits you have to trim off up the walls?

[Sunnynshare]

Have never had the problem, but maybe a 1" or 2" sheet of Styrofoam under your mattress and run the bits you have to trim off up the walls?

A one inch 4x8 sheet of RMAX, foiled on both sides, non compressable foam insulation cost 20 dollars at Home Depot when I got it last night.

[vwbitts]

I used the double bubble foil insulation.

FOIL --here----

[punter]

Thank you all. I've got the foil sided bubble wrap up there now, but it hasn't stopped the condensation buildup. Now have the condensation both under and on top of the insulation.... Will give a try with the other suggestions next. Beginning to think I've got a water bed up there.... Thanks again!

[toyboxII]

Hi--we are watching the responses along with you as we have the same problem. DW and I fulltime in our 92 Itasca Spirit. We have a memory foam topper on the original sleeper mattress.

We winter in Florida and for the past two years, it has been cold requiring heat. I have installed the solid, foil-covered sheet of styrofoam (Thermax) under the mattresses and still have condensation. Next we added a marine product called Hypervent (expensive) which is supposed to solve this problem. It hasn't. Now I am thinking about building some kind of framework to raise the entire mattress off the cabover and build in some kind of powered ventilation system to keep the air moving under everything. Hoping that this, along with both roof vents open (we never close either the front or the back vents), will help with this problem. Presently we make sure we remove eveything from the cabover at least one a month to ventilate and dry out. Sure hope someone out there who has solved this problem will response. Good luck in you search for a cure!

[punter]

Thank you for sharing your experience, toyboxII. Since I now know what you've tried and found to be less than successful, I'll just skip them and go on to what my nephew suggested. He said perhaps get 1" X 2" boards (wood or styrofoam) cut to fit front to back (shorter for in front of cab opening) and place on deck about 6 to 8" apart to keep mattress up from the deck but allow air flow thru from the camper area, without adding too much weight up there. The 1" won't make too much of a difference on sleeping comfort but should allow air thru sufficiently. We hope.... Since I didn't pack a saw on this adventure I'll have to get one of those, too, cause no doubt Lowe's or HD will not have such slats in the exact sizes I'll need.... :*) I, too, have to take the cab-access piece off and raise the mattress (using 5 upturned camping bowls -strategically placed!:*) about 3 times a month to wipe up and let dry all out. When it's only 20 degrees outside all this has to be done "in house". The condensation is most prevalent under where the bottom of the mattress is covered in vinyl. Don't know if that has anything to do with it or not, but it's noticeable in mine - a '92 Warrior with original mattress. As for leaving roof vents open? Not me! Had one cold spell here when it didn't get above 28 for 6 days and nights in single digits. My little 7 gal propane tank ran out in 56 hours (8:00 p.m. on a Saturday night at 15 degrees out....). A learning situation! Thanks again for letting me know of your experience.

[toyboxII]

Hey again--thanks for sharing. Sounds like great minds think alike! Like you, I am away from our home base where I have tools, so my plans will have to wait until this summer. I too will raise my entire mattress to allow air flow, but I want to add some kind of fan to force the air to move hopefully eliminating the condensation. As to your ventilation using roof vents, we can notice the difference when we try to close up. Moisture builds up quickly despite efforts to use roof fan when cooking or showering. With the vents open, no problem. Agree with you findings on propane use, but we depend on a small ceramic heater instead of the furnace and find that it keeps us quite comfortable. We also have been in freezing temperatures for weeks at a time and we stay quite comfortable. We run the furnace first thing in the morning to quickly remove the chill then switch to the electric to hold the temperature. We also installed a Hot Rodd kit on the water heater and were astonded at the propane savings. Never realized just how much propane it took to keep hot water! Our little propane tank last a long time that way. Part of the "fun" of owning a Toyhome is finding new and better ways to do things. Best of luck to you.

[Derek up North]

http://www.pplmotorhomes.com/parts/rv-water-heaters/hott-rod-kit-lightning.htm

http://www.pplmotorhomes.com/parts/rv-water-heaters/hott-rod-water-heater.htm

[DanAatTheCape]

Hello all. Am staying in my motorhome for the moment and it can get cold here. Condensation is building up inside under my over-cab mattress around the outer edges beyond the cab. Has anyone had this problem and successfully thwarted it once and for all? Many thanks.

any chance that your front window is leaking? Also in cold wx that window could be your source (condensation on the glass) -- I am wondering if a towel or some sort of setup to catch the moisture before it runs downhill/

in my first camper the front window leaked occasionally - came thru between the glass & the window frame. I took some plastic sheeting & formed a tray using tape - it looked like crap but it stopped most of the problem.

[85mirage]

i too have condesation under mattress. Just thought it was my windows leaking. oh boy

[punter]

i too have condesation under mattress. Just thought it was my windows leaking. oh boy

Aren't you glad to see you're not alone??

I do have some build up at the bottom of the front window inside that drips down when there's snow melting off the roof, but that couldn't account for the moisture under the sides the way it is in patches. I'm still wondering if it has something to do with that plastic(vinyl?)-bottomed mattress. May be a combination of things, but it sure can accumulate a lot of water under there. I'll try the slats, and if I keep this lovely little motorhome, maybe I'll find someone who can take that front window out altogether. Board it up with duct tape myself if I have to! This living in a camper in the winter has taught me a lot - holding tanks freeze!, an old furnace is NOT worth trying to fix for the 3rd time in 8 days - it's worth the big bucks to get a new one!, the little curtain between the cab and the camper can be replaced by a thick comforter, and weather stripping is not enough at the bottom of the door!! Oh, and the propane tank is waaaayyyyy too tiny in these Toys, and just because the vendor's meter isn't working doesn't mean your tank hasn't been filled - tho you can't be sure because your gauge doesn't work so you have to burn it off before the repair guy can take a look at it and you find it WAS filled because it's taking days to empty (so you got a free tank of propane).... But even with all those happenstances, I am having quite a fun time. Hope all of you are, too. And I thank you all for sharing your knowledge with me. This is a good group.

[Derek up North]

Where is it that you're having all this fun?

[punter]

Where is it that you're having all this fun?

East of the Cascades in Oregon. 12" of the white stuff on Tuesday morn. 4" more on the ground this a.m. Have my very own snow shovel stored in the shower stall. Know how to wield it - of necessity!

[84TOYRV]

Do you ever think about spending winter in warmer climes? I'd be AZ bound, in heartbeat!

[Totem]

Late post but same problem... It's mid winter 2013 and the last time I used rig was Nov 2012. Went out to rig today, and there were condensation ice flows that had iced the mattress to the cab bed floor. Windows aren't leaking. It's like the moisture in a terrarium that froze. Trying to wrap my mind around drying the rig out up there...or a permanent solution. It would seem the overhead cab bed area is colder than the rest of the rig. Unsure of a good fix other than heat which isn't practical for storage. Channeling the falling water seems like the only power neutral approach...

[Dolphinite no longer here]

I have a condensation problem too, only mine is under the rear dinette mattress since that's where I sleep. When the heat from a warm body migrates through the mattresss and hits the cold bunk boards the warm air cools and condenses on the wood under the mattress. Since I make the bed back into a dinette every morning, everything can dry out during the day. I've haven't found anything that will insulate well enough to prevent this condensation problem but I'll bet something is out there that'll do the job.

John

[waiter]

I leave one of the roof vents open when I store the toyhouse. (I have a MaxxAir cover on the vent I leave open) I've never seen any moisture on the inside when I do this.

John Mc

88 Dolphin 4 Auto

[Totem]

I have a condensation problem too, only mine is under the rear dinette mattress since that's where I sleep. When the heat from a warm body migrates through the mattresss and hits the cold bunk boards the warm air cools and condenses on the wood under the mattress. Since I make the bed back into a dinette every morning, everything can dry out during the day. I've haven't found anything that will insulate well enough to prevent this condensation problem but I'll bet something is out there that'll do the job.

John

Yeah but what if no one has been sleeping out there for 2 months? Maybe it was still there from deer camp week and never left. It's the condensation on the inside front cab bed windows that bugs me, as it suggests high moisture interior. There must either be a leak or a big need to dehumidify after a week of winter camping maybe. I don't see this phenomenon in the hot summer, only in cold.

My current plan is to let it dry with a heater, clean mildew, apply hypervent and maybe add a solar powered venting fan. The brookstone bed fan shows promise; 12 volts one amp. Now I just need a humidity based switch ... I will install it aiming into the hypervent . Should make for a nicer july sleep too.

[waiter]

Sounds like you may have water leaking in.

Look at the front window frame, see if there is any water in the frame. There are no drains on the front window frame, so if any water gets past the rubber keeper, it can fill the frame with water, then it spills over to the interior.

Double check the side windows, to make sure the drains are not plugged.

If its just condensation collecting, Venting will help the air move in and out of the toyhouse. I would think if it is just condensation, it would only show up occasionally, but would ultimately dry out.

John Mc

88 Dolphin 4 Auto

[Maineah]

Sitting in the bright sun during the day? Warm air holds more moisture then cold and it will condense on the cold glass. I agree with waiter I think it needs venting that also will help keep the inside and outside temps the same..

[Totem]

yeah no water comming through seals; they look spanking new and freshly caulked. show no signs. the flows are definately condensation ones. when camping the windows were all completely fogged out in Nov every morning. I would open windows to vent. Now its winterized and shut up. I never thought about it but I bet the underside matress was soaked from that week and is evaporating slowly back into cab.

I will re caulk window frames also. The side window drains are free and clear both in cab and regular large wall windows..

I can see where condensation dripped down the inside of those too. the thing must be like a terrarium. Maybe i will run space heater AND dehumidifier.

[craige]

The material looks similar to the stuff I used on the top of my roof under the shingles at ridge. I have a whole roll left over. I like trying things that are free.

[Sunrading Arkansas]

@Totem - Any resolution/fix for your condensation issue. I have been experiencing the same, any part above the "exteriorly exposed" overcab covered by the mattress (plastic bottomed) gets wet cold fronts come in or while cold-weather camping...had one come through last night and wet this morning. The previous owner resealed all the windows and they are not leaking, so 99% sure it's not from the windows. Once I replace the A/C with a Fan-tastic/Maxx Fan hopefully I can ventilate it better and resolve the issue....for now I'm putting the dehumidifier & heater in there.

[Totem]

Resolution, yes . And I was quite correct. Just sleeping in your motor home introduces tons of moisture. think of a cold dry day in winter; you see your breath as a smokey vapor. well inside your warm motor-home that vapor is still there just invisible. I pulled my full sized 110V basement dehumidifier from its favorite basement alcove and lugged it up to Rocket.

Ran it for a few days in this warmer weather. I got couple gallons, then it tapered off to nothing.

So there you have it; just putting a mesh down under the mattress or insulating is not enough; what we need is a dehumidifier.

Now I will say this Linda S. gave me some links to mini motor home ones that seemed pretty good; however some of them have fire risk associated with them and or bad reviews from amazon. I am glad you posted on this recently S.Arkansas, it reminded me of this issue and the fact we just had guests stay in our camper for a weekend. Time for me to go dehumidify. We need a post on the best motor-home dehumidifier and cross reference against amazon reviews.

[Totem]

the problem with them including the wind-chaser is the power supply. apparently it burns out and or catches on fire. maybe i could just straight wire on to a voltaic panel and take the transformer out of the picture?...need the electrical crew to weigh in on this.. JDE, Stamar, Maineah, John?

I'm thinking desiccant may be the holy grail...

http://www.amazon.com/Eva-Dry-EDV300-Mini-Dehumidifier-Dampness-protection/dp/B0046ZDR3W/ref=sr_1_1?ie=UTF8&qid=1365772935&sr=8-1&keywords=Windchaser+Small+Dehumidifier

with the understanding that the devices would go under the bed in places, then moved out and plugged in while on the road with windows open etc.

[linda s]

Since it's your moist breath condensing on the window another low tech sloution is to keep the window protected from it. Some reflectix cut to fit the window tightly will insulate and reduce condensation a lot. Maybe even one big piece that wraps all the way aound the front overhead. Be warmer inside too

Linda S

[Stevo]

Did anyone come up with a cheap solution that doesn't take away much headroom from the overcab area yet?

[Dolphinite no longer here]

I use a couple, maybe three, 1" x 2" boards that I shove under the mattress after I get up. Everything is nice and dry by about noon or so.

John

[Stevo]

I asked this question because I've spent a lot of time around sailboats and condensation forming under mattresses and then getting moldy is fairly common. I haven't experienced it yet but I figured there might be a similar issue with motorhomes and especially if they are in damp rainy areas. Hmmm, so maybe between removing those front Sunrader wrap-around windows and all new insulation inside with Reflectix will minimize the issue?

Since it's your moist breath condensing on the window another low tech sloution is to keep the window protected from it. Some reflectix cut to fit the window tightly will insulate and reduce condensation a lot. Maybe even one big piece that wraps all the way aound the front overhead. Be warmer inside too

Linda S

[Totem]

except its not just condensing on the windows.... its literally doing the same thing it does in a boat; condensing on any firberglass surface sepecially the overhead bed cab floor...its outside facing cold and low lying. gravity and the outside temperature difference are your enemies. Anything cold will attract moisture from warmer air. I am off the opinion the thing will weep even without people from this effect unless something stabilizes/equalizes the inside and outside air temps. I believe Waiter said that in here he keeps vents and windows open all the time; that would do it but alas then rain can get in if you aren't sporting fancy max air vents and even then some might get in. Alas its a battle that requires the owner to periodically check cushions, no way around that shy of putting a heating mesh (like for under tile flooring) down under the bed and I am not sure how safe that would be.

by insulating your rig further you only make the effect worse trapping warmer moister air inside. the reflectix could work but it would need to be glued to the surface with no inside air exposure.

[MontanaChinook]

Yep, my cab over floor gets water running on it in the summertime in Montana, with no one sleeping up there. We are usually in the teens, as far as relative humidity. What we do get is a big swing in temps between night and day. It can be 95 during the day and it will still often get down into the 50s or even 40s at night in the summer.

Those cab overs are just a magnet for condensation.

[Totem]

its physics;

in winter it is the reason why we need humidifiers; cold air does not harbor the capacity to carry humidity as well as warmer air. The delta between the two causes colder air when warmed to become very dry in terms of its humidity saturation level. This is the principle that the golden rod dehumidfiers work on for gun cabinets; all they do is act as a small heating element to raise the ambient air temperature inside a gun safe to be slightly higher than the outside air of the cabinet; hence the air dries out. since the delta between the two is not that drastic there is no sweating and thus your guns enjoy a low humidty rust free environment.

However a cold surface present in a warmer humid aired environment will sweat as it draws moisture from that air to the surface in the phenomenon known as condensation; The reality is that anything thats open aired with humidty will sweat onto the colder surfaces; even in your walls in between the wood paneling and the cold exterior fiberglass exoskeleton of the Sunrader. I suspect that many a stain or water trail that a toyhome owner thinks is comming from leaking windows would prove in fact to be a condensation stream.

[WME]

OK all you dripping wet crafty people, here ya go just what the doctor ordered.

http://makezine.com/projects/heat-exchanger/