Drymesh or hypervent under matress

[Sisababe]

Originally Posted by stephen99

I am interested. I tried to go through the ordering process on the English website but in the end it only said we will contact you via email. Haven't heard anything yet but I expect shipping is awful.

I have sent them an inquiry about distribution in US. You are right that shipping a small amount would likely not be worth the cost. If there is enough interest to make wholesale quantities worthwhile though, it may be worth investigating. Shipping cost are more reasonable when spread across a bulk shipment.

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[Mike & Donna]

Originally Posted by Sisababe

How much interest is there in the DryMesh product? My husband and I own and operate several e-commerce websites so we have import and distribution

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Don't know anything about it or the hypervent product that has been under discussion lately. Didn't realize I would have to put something under the mattress to allow for air circulation. Is this just for the folks up north are does it apply to us in the South? If I should have it then I guess I better start learning about it so i can get the one that's best for my situation. Will add it to the list of things I need to do.

[casejh]

I too would be interested in the Drymesh product if we could get it at a reasonable cost.

[thoer]

Originally Posted by Sisababe

I have sent them an inquiry about distribution in US. You are right that shipping a small amount would likely not be worth the cost. If there is enough interest to make wholesale quantities worthwhile though, it may be worth investigating. Shipping cost are more reasonable when spread across a bulk shipment.

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Keep us posted if you set up something with them.

[cpaharley2008]

This dry mesh/hypervent has been used for awhile in boats. If you have ever slept on a boat you have experienced condensation while below. Although sleeping in your camper is a little more refreshing, one can still have the side effects the the in/out door temperature change and humidity issues. This items tries to mitigate the end results. Adapting other known products to our use has been part of the exploring items to make the camping experience more comfortable and enjoyable.

[nrthwds]

Sign me up too if you can get the Drymesh product at a reasonable cost. Keep us updated!
Thanks

[rbryan4]

Hypervent is available from Fisheries Supply, but I'd need 13 feet of it for two 39" wide runs of 80" long. That's about $150. Ouch.

[cpaharley2008]

Actually 10 feet would work Robert, 2 strips of 39' wide x5'+ 39" wide x5' would give you 78"x60"

[rbryan4]

Originally Posted by cpaharley2008

Actually 10 feet would work Robert, 2 strips of 39' wide x5'+ 39" wide x5' would give you 78"x60"

Yeah, that's right, the bed is only 60" wide. So, around $115.

But, since I've not had any issues so far with condensation under the mattress, I'll need some convincing.

[tdf-texas]

Originally Posted by rbryan4

But, since I've not had any issues so far with condensation under the mattress, I'll need some convincing.

On the trip back from Chilliwack a week ago, we didn't have any condensation problems under the bed. However, the walls would get wet behind the cushions and along the edges of the bed.

Other than reducing the moisture in the trailer, how do you prevent this?

[cpaharley2008]

Allow air to circulate between wall and mattress, move mattress as far over against bath wall and away from front wall.

[paulk]

Originally Posted by Tom W

No moisture would get through the vinyl anyway.

What I've read online agrees with Tom that vinyl is vapor impermeable. I don't see how any moisture could reach the drymesh or hypervent if used under the dinette bed given that there is vinyl on the bottom of those cushions. On trailers with permanent beds, ETI is now using coil mattresses in order to prevent the moisure issues that were experienced with previous foam mattresses. I guess the coil mattresses have enough internal air flow to prevent moisture buildup in normal conditions.

So, is drymesh or hypervent still relevant today for anyone with a newer ETI trailer? I guess one possibility for the dinette bed might be to purcahse cusions with fabric on both sides so that the moisture could reach the drymesh/hypervent layer underneath, but cusions without vinyl seem to be rare, and not the default option.

[cpaharley2008]

I believe the issue is created when a warm body sleeps on the dinette and the area underneath is unheated and cold. Thus moisture may be present underneath as well as around the perimeter where the cold wall and warm cushion meet. Similarly in the bed area, underneath as well as around the perimeter. Either vent the underbed/dinette area to allow heat and air to circulate or pull the item away from the wall to allow air to circulate. The hyper mesh creates that air barrier. Right now I'm using reflectix around and under the bed to see if that works.

[paulk]

That's a good point cpaharley. The marketing material that I've seen on these products seems to indicate that warming the underside of the bed is one of the benefits, and the other being direct moisture transport out through convection. It's not clear to me which is a bigger factor though.

It seems to me that the issue of having heat under the bed could be better addressed by putting vent holes into the storage areas under the bed. That has the benefit of not requiring this extra bedding layer that would have to be managed. On a permanent bed installation it's probably not a big deal, but it would be more so if the bed was being made every day and the drymesh/hypervent layer took up valuable storage space, and also the added fiddly factor.

I found this build sheet of someone who asked ETI to add vent holes. It's listed as “Vents under bed and benches” :
http://www.escapeforum.org/forums/f3...na-2499.html#6

And here is a picture of the vents:

http://www.escapeforum.org/forums/at...3&d=1388789205

[cpaharley2008]

I have purchased some myself to install, easy to drill and push into hole, it is on my list, see attached

[Ron in BC]

Originally Posted by paulk

It seems to me that the issue of having heat under the bed could be better addressed by putting vent holes into the storage areas under the bed. That has the benefit of not requiring this extra bedding layer that would have to be managed.

http://www.escapeforum.org/forums/at...3&d=1388789205

I'd never put vents from the storage area to the underside of the mattress. That area isn't well insulated, it's a very cold area and I treat it like an unheated crawlspace. Heck, I even insulated the underside of the bed platform when I installed my Ikea slatted bed base. More comfortable and provides maximum ventilation to the underside of the mattress.

During our recent extended trip in freezing and wet weather we had zero issues with any dampness on the perimeter of the mattress.

Ron

[paulk]

Putting vents going from the cold storage spaces to the underside of the mattress would indeed be a bad idea. I can see that I wasn't very clear in the text of my post. The proposal was for putting vent holes from the storage spaces to the main airspace of the trailer via the lower walls of the benches (see picture for a visual). That should allow warm air heated by the furnace to enter and heat the storage spaces, and make the underside of the bed warmer.

[cpaharley2008]

Yes vents in vertical sidewalls not the the horizontal surfaces.

[paulk]

I've been thinking about the problem over the weekend and I believe I understand it a bit better now. I live in Seattle, and plan to use the trailer in cold weather, so condensation is a key issue that I'd like to resolve before it becomes a problem.

From the discussion above, I was considering just ventilating the cabinets and seeing if that addresses the issue without the need for drymesh or hypervent. Now that I've thought about it, I think in some conditions the hypervent/drymesh is still important.

I found this other thread in which a couple was experiencing condensation on the underside of their table, which was open to the main airspace, and was additionally actively heated:
overnight condensation under bedding - Fiberglass RV

I think the mechanism at play here is that your body is 98 degrees Fahrenheit, and even if the bench below is heated to room temperature, that's still 30 degrees Fahrenheit cooler than your body. If your body continues to expel moisture into the bedding without that moisture having a way to escape, then eventually you'll see condensation inside or under the bedding when it reaches the cooler 68 degree Fahrenheit room temperature surface under the bed.

Of course, if you don't ventilate the trailer properly, then eventually relative humidity will build until water condenses somewhere inside the trailer, but I think the bed is a special microclimate that could see condensation even if the rest of the trailer is adequately ventilated due to the fact your body is so humid and warm and the rest of the trailer is in comparison quite cold even if comfortably heated to room temperature.

One interesting tidbit of information that I learned looking at water saturation tables is that it's a good rule of thumb that within the range of normal human temperatures (-40 Celsius to 40 Celsius) air can roughly hold twice as much water for every 10 degrees Celsius rise. So, air at 37 Celsius can hold a bit shy of 4 times more water than air at 20 degrees Celsius.

So, although ventilation under the bed will probably help, and may resolve the issue in some cases, I think I’ll also add drymesh under the bed and along the sides and also ask to have cushions with fabric on both sides to allow moisture transport to the drymesh layer. I’ll also request ventilation holes added to the storage spaces. Escape said these would be $10 each.

For the vent holes, I was thinking having one at the top and one at the bottom on opposite front/back sides of each storage area. That should allow a circulation effect to work where hot air enters the top vent and cold air exits the bottom vent with a cross ventilation effect across the entire length. The converter on the 17b already has holes, so I only need one vent on the driver side dinette storage area.

[NW Cat Owner]

Originally Posted by paulk

(snip) So, although ventilation under the bed will probably help, and may resolve the issue in some cases, I think I’ll also add drymesh under the bed and along the sides and also ask to have cushions with fabric on both sides to allow moisture transport to the drymesh layer. I’ll also request ventilation holes added to the storage spaces. Escape said these would be $10 each.

Well, when you get ready to get the hypervent, you're practically next door to Fisheries Supply, which is where I got mine at. And you won't have to pay shipping charges! North Lake Union (one time we went, as we headed out, we saw some female bicyclists from the Solstice Parade - Dirk was thrilled!).

If you're getting fabric on both sides of your cushions, make sure it's on your build sheet. Don't rely on any emails to that effect. I speak from experience on that particular issue.

And for 10 bucks each, if you have a drill, I'd do it myself. And yeah, I could do that myself. And not rely on Dirk.