I'll bet you, that you never thought of the following...

[Sun_Seeker]

I was just on another site, and a very interesting thread was going on, about any floor plan TT or RV, that might have a bed reside in a slide out, or over a storage area, that would expose the underside of the mattress (bed support) to the cold, if camping in early Spring or Late Fall..or outright Winter camping.

A person noticed an off odor, coming from their bed/mattress and thought to lift up the mattress and observed that the mattress bottom was wet...and already showed signs of a mold presence (hence, the start of an odor). They had no seal or roof leak..to account for this...so were very upset, and puzzled...

The person stating for them, where to look and to why this is happening...(wet mattress under bottom) is that the bed frame support and the plywood underlay that your mattress lays upon, gets cold transference from the locker/storage area, or from the slide being out and exposed to the outside-of-the-body-of-the TT/RV wind and temperature elements.

Then, your body moisture is taken up by your mattress, and as it wicks down to the cold side of your mattress, made cold by contact with the cold plywood under deck...the moisture condenses...and condenses enough to make the mattress damp, or even outright wet.

The solution is easy-peasy. Go to Home Depot, (or where ever), and buy a 1/2 inch thick house wall insulation foam board (the one with the one side having the foil) and cutting it to size for your plywood underlay, place it on top of the plywood underlay, with the FOIL side facing up. Then place your bed mattress upon that sheet. Done...your mattress is now insulated from the direct cold, plywood underlay, that is directly sitting over your non-insulated storage locker, or it made cold, because your bed is in a slide out...and being outside the trailer...exposed to the cold from the slide under bottom.

A good tip..and one that I am certainly going out to act on. 1/2 foam wall board with foil on one side...will be purchased and installed under my Queen bed in my Micro Minnie 1706FB, which does sit in fact right over the front storage locker.

A good explanation of what was happening to that couple's mattress and probably to everybody else, too... I didn't think of the bottom of the mattress getting cold and condensing...and I bet dollars to donuts, that the reader, reading this, never gave it any thought either! Now, you are informed! BTW, their bed was partly in a slide out environment...

[SLOweather]

It also happens under mattresses on pedestals over rear trunks, as in our Sunstar. When I figured out what was happening, I glued and screwed inch and a half rigid foam insulation to the underside of the "ceiling" of the trunk to insulate it.

[Sun_Seeker]

Originally Posted by SLOweather

It also happens under mattresses on pedestals over rear trunks, as in our Sunstar. When I figured out what was happening, I glued and screwed inch and a half rigid foam insulation to the underside of the "ceiling" of the trunk to insulate it.

I think that I will follow up what you also did...I'll put an insulation layer, on my 1706FB's front locker ceiling. I'm sure you can't 'overkill' such things...(large smile!).

I don't want any problems from our mattress...so...I'll do under the mattress, and as you did...---->on top of the storage locker, against the ceiling.

DONE!

[rarebear.nm]

A similar solution learned from winter tent camping on snow is to use a space blanket under your bed. The foil covered board is better. But in like over head bunks of some rigs the space blanket would be easier to use.

Also be aware of condensation forming on exterior side walls next to the mattress. Been there.

[SLOweather]

In this way, our past Suncruiser was superior to our current Sunstar. The Suncruiser's rear queen was over a full size above floor storage space, while the Sunstar's RQ bed is half over an above floor storage space, and half over the trunk.


Plus, in the Suncruiser, there was a rear window. We got condensation from that. I never thought about the rear wall. The Sunstar has a solid rear wall, so the window is not an issue.

[Upinsmoke]

It's certainly a point worth considering. I have a spare "remote" thermometer I'll place in there while we're camping and see what kind of temp differences there are and go from there.

As SLO indicated, our Sunstars bed is only partially outside the RV but still worth investigating. I haven't ever noticed any sort of moisture but I'll for sure be on the look out now.

[SLOweather]

Originally Posted by Upinsmoke

I haven't ever noticed any sort of moisture but I'll for sure be on the look out now.

It can be subtle. I noticed it only because, in a hurry, we had stashed an envelope with some papers in it under the mattress. When I retrieved the envelope, it was dry, but it was clear that it had gotten wet or damp, as the security printing ink on the inside of the envelope had run. That was after our big trip a year ago, when some nights the outdoor temps got to 30F or below.

[Upinsmoke]

SLO, could you clear something up for me. Where did you put the insulation? Are you considering the piece of wood(?) upon which the mattress sits (the one that lifts up) as the lid of the trunk - or did you remove the piece of plywood which serves as the "roof" of the platform and put it there. If you have any pics, that might help.

Although I do everything possible to avoid cold weather, 2 years ago we were in (very) freezing for days on end! It wasn't fun The pictures are from 4 days in Charleston!

[Sun_Seeker]

Originally Posted by rarebear.nm

A similar solution learned from winter tent camping on snow is to use a space blanket under your bed. The foil covered board is better. But in like over head bunks of some rigs the space blanket would be easier to use.

Also be aware of condensation forming on exterior side walls next to the mattress. Been there.

Good point about the cold wall of the TT or RV doing its 'thang' on the mattress vertical side. Thanks for adding to the thread, and everybody else, of course!

RV forums are simply the best...for had I not read that thread...I would NOT have even thought on my own, about a mattress being affected by a cold underlay...well, until it was too late, as that couple had to purchase another mattress!

[SLOweather]

Originally Posted by Upinsmoke

Where did you put the insulation? Are you considering the piece of wood(?) upon which the mattress sits (the one that lifts up) as the lid of the trunk - or did you remove the piece of plywood which serves as the "roof" of the platform and put it there. If you have any pics, that might help.

I cut 2 pieces of 1 1/2" rigid foam insulation to fit the ceiling of the trunk. I thought about gluing them in, but decided that it would be a mess if I ever had to remove it.


Off to the right are a couple of big hooks to hold the window scrubber and squeegees. Hanging them there keeps the squeegee rubber from getting deformed in storage.



So, they are held up with a grid of construction screws and fender washers. I ensured that the length of the screws was shorter than the thickness of the foam combined with the thickness of the plywood deck.


Come to think of it.... This time last week we were in the Sierra near the entrance to Sequoia NP, at Three Rivers. It got into the low 40s and high 30s at night, and I was wondering why I wasn't colder in bed overnight. I think the foam made a noticeable difference there.

[powercat_ras]

Any Winnebago that has a fuse / circuit breaker box under the bed also can be improved. Lift up the bed base and you'll see a plywood box around the back side of it. Below that box is a huge hole in the insulated floor that the power in/out cables are run thru. In my Vista that area below the floor is within the basement area where the water tank and access compartment where water and power access are provided. The box is not insulated. On my Vista, after lifting the access cover I found there was room to put insulation against the plywood walls and on top below the access cover to cut down on the heat loss. I also installed insulation below the floor to cut down on the heat loss thru the floor, side, and back walls of that basement area access compartment. I used inexpensive 3/4" polystyrene panels, come in packs of 6: 14.5 x 48 x 3/4 panels for about $ 7 each at home centers.

[Upinsmoke]

SLO, I must be a little dense, I didn't realize our beds must be different as our bed is on a slide out, the mattress lifts to expose a small (in depth) but full width compartment. My guess is that it's 3/4 in. plywood or something similar.

Then this all sits atop a boxed in area which is inaccessible unless you lift the bed platform and remove a bunch of screws. I've never noticed any condensation anywhere in the RV (although I'll be looking more now) and I'm wondering if this construction might be the reason?


I'll include a couple of pics of this also. The first is a technician under the mattress area, bed raised, and he's removing the "top" to the box are below. This was during new owner orientation. The second pic shows essentially what's in the bottom area which I see no need to access regularly.


So, I guess for now, I'll take a wait a see. There's always enough stuff to fix that needs it, I don't want to fix stuff that don't!

[BobC]

There are a variety of products available that would allow for air circulation under the mattress. Some are made for the purpose:

https://www.amazon.com/s?k=anti+cond...l_5cn15vj0bb_b

It might not be practical in an RV, but in my sailboat I used to up-end the mattresses in the winter.