Mattresses Moisture Argh!

[swami maximus]

Hello.
I was wondering if anyone has some good homemade suggestions for dealing with mattress moisture. I have searched these forums but cant seem to find anything that specifically address this issue. A lot of talk about it, but not much on what to do with it. I was thinking of either taking the mattress out and drying it thoroughly, then covering it with a plastic of sorts to prevent penetrating moisture. OR... getting a bunch of milk crates and cutting them apart to form a grid and then using thick mesh to keep my foam from filling the small squares of the grid. Bunk, grid, mesh, mattress... Sound good or does anyone have a better idea?

[ssullivan]

Moisture is a fairly simple thing to understand. In a relatively humid environment, if you have a cold surface that is below the dew point in the air, water will condense out of the air onto that surface.

The trick is to eliminate any of the following:

*The moisture in the air (dehumidifier)
*The cold surface (make it warmer)

Also, as you hinted, air circulation will help bring less humid air in than the air you are breathing out while on the mattress.

The grid idea will work. The plastic wrap... not so good because your bedding will get wet even if your mattress doesn't.

The condensation typically forms not on your mattress, but on the surface that you mattress rests on. Try the milk crate idea first, or if you have moisture in a lot of spots, it might be time for a dehumidifier.

[Alan Wheeler]

Most of the moisture in a matress is actually from our bodies. Our bodies will expell a tremendouse amount of moisture over night. And the amount increases with the more activity in bed....hey get your mind out of the gutter, I meant like pillow fighting.
Air circulation is crticle. Free air movement must get under the matress and be able to flow up through it. Vents in the base that the matress rests on is essential. Egg crates will not allow air to move. Slats are best, many holes second. A dehumidifier works well, but does not do a "best" job only drying air in the mattress from the top. If you can get a dehumidifier or it's dried air uder you matress, it will make a world of difference.
There several major health benifits in having a dry matress, but one most noticable result is the bed feeling warmer and it warms from your body heat faster, even though the air in the room is still cold.

[delmarrey]

You need to keep the inside air warmer then the outside air, all the time.
I keep (3) 250w lamps burning when I'm not aboard......................_/)

[ssullivan]

Wheels, I think there is a cultural or dialect difference. To us, a "milk crate" is a kind of slats system:

http://calgaryplastic.ca/milk%20crate.gif

He was talking about cutting one up and using it to improve air circulation (I think).

[svHyLyte]

Another alternative is to add a layer of Reflectix foil covered duct insulation to the underside of the berth supports to insulate the structure from the cooler spaces below and then add a layer of DriDek under the mattress to allow air to circulate. As most of the moisture does come from one's body, the idea of wrapping the foam pad in a layer of light plastic has merit. Adding a simple batting cover to this and then covering the batting with a mattress pad works well. We had a mattress cover made with light weight Sunbrella sides and top and a plastic mesh bottom that, with the foregoing suggestions, has proven very effective at keeping our berths dry and comfortable.

s/v HyLyte

[ssullivan]

Hmm... maybe the plastic does have merit in the climates you guys are in.

Up in the high latts, the moisture on a mattress comes from condensation on the surface below the mattress. The cold in the compartment below the surface causes any moisture to quickly condense (body sweat, breathing or ambient moisture).


Plastic doesn't work in this situation, since your "tucked in" sheets and blankets are below the mattress and end up working like little capillary tubes, drawing the moisture below the mattress up and onto the bed.

Sounds like you guys are describing a different type of mattress moisture than I am usually troubled by.

[Squeaks]

Venting below the matress seems critical for good air circulation. I have pieced together a grid made from the interlocking square foot-sized plastic pieces from West marine called Dri-Dek. It seems very efficient.
West Marine: Dri-Dek Product Display

Self-draining, interlocking panels provide a ventilated surface that helps keep stowed gear dry and free from mildew and odor. Made from oxy-B1 vinyl, they inhibit bacterial growth by limiting germs’ ability to absorb oxygen. Use Dri-Dek to line the bottoms of compartments, cabinets, lockers or the space under bedding and cushions to promote air circulation and eliminate trapped moisture. Use it under anchors, gas tanks or loose equipment to protect wood and fiberglass from abrasion.

• 12" x 12" panels, sold individually, may be trimmed easily for a custom fit

[hellosailor]

Swami, no doubt you've seen "plastic steel wool" or other "spun-bonded" plastic materials used as pot scrubbers?

Well, that stuff was invented as a road underlayment/drainage material, and is still sold in landscaping suppliers in big rolls. What you want is to buy just a couple of yards of it, and place it under the mattress. That will allow air circulation under the mattress so the moisture can escape. Not very expensive, just not the kind of thing your ordinary local garden supplier will sell by the yard, either.<G>

[Evan]

Ahh the marine world has "re-invented" the landscaping drainage stuff as "Ventair" and sells it for $$ / ft. But its the same stuff. Works well though.

I used cedar lattice fencing on our old boat. The lattice is very open and allowed lots of air circulation under the matteress. Also the cedar is nice smelling

[Alan Wheeler]

Wheels, I think there is a cultural or dialect difference. To us, a "milk crate" is a kind of slats system:

Arr right. Got ya. For some stupid reason I had Egg crates in my mind.
And Evan bet me to it with the Ventair.

[Mike Banks]

Not only does one need the ventillation under the mattress--one also needs to drill holes in the side of the retaining board alongside the drainage material so that air can pump in and out as one shifts position. One can also ventillate under the bunks, cupboards etc via a small fan such as a computer cooling fan and allow the air to escape through the screened holes you need to drill. One can glue mesh over these holes if one has other pests aboard--otherwise one has just provided the cockroach hilton.

It is always a good idea in the Land of Oz to have reasonably fresh "nest kill" type cockroach baits aboard--and another deterrent to the pests is borax sprinkled around the place and in the bilges. Putting some borax under the bunks ventillation matting might be a good idea too--it lasts indefinitely, and can be vacuumed up easily.

[swami maximus]

ssullivan you are correct, that is exactly what i was referring to. hello sailor, i have been wondering where to find that stuff. i used to work for a commercial floor cleaner in highschool, and recall the round scrubing mats that the machines used, and i thought those would be perfect. at a landscaping place so you say? i will check it out and return and report. thanks for the tips! and the ceder sounds nice too.. smellwise.

[lovsailing]

all great ideas......but......we have found that a small electric oil rad under the bunk to be the only answer. it warms the air under the bunk and warms the matress a bit as well. 4 winters in toronto canada, and we have zero condensation. the rad draws 3 amps AC and is completely safe secured in a upright position and there are no moving parts. just a thought.......

[first wind]

Originally Posted by lovsailing

all great ideas......but......we have found that a small electric oil rad under the bunk to be the only answer. it warms the air under the bunk and warms the matress a bit as well. 4 winters in toronto canada, and we have zero condensation. the rad draws 3 amps AC and is completely safe secured in a upright position and there are no moving parts. just a thought.......

i use one of those stand up units to heat my cabin but, there is no way i could fit it under the v-berth. do they make them in a lay down format?