Condensation mats

  • HTML tutorial

Baymax21

Rank II

Contributor III

327
Geneva Illinois
First Name
Vincent
Last Name
Pekarek
Member #

29368

Hey y'all we're new to RTT life and wanted to find a way to mitigate condensation that isnt overly expensive. Any tip/tricks or gear advise would be greatly appreciated. Thanks!
 
  • Like
Reactions: MegaBug and Road

MegaBug

Rank VII
Launch Member

Influencer II

6,414
Colwood, BC, Canada
First Name
Matt
Last Name
Lester
Member #

20270

It's all about ventilation. We give off a lot of moisture as we sleep and good airflow is crucial. When it gets cold we tend to close off the outdoors but the accumulating moisture just makes you colder in the long run. Better to ”open up and cover up” ... more ventilation and more blankets. Of course screening is also important in the warmer weather so we can open up without getting eaten up :-)
I learned this the hard way when sleeping in the back of my vehicle and eventually made a screened insert so I could leave a back window wide open.
So ... to answer your question the solution is actually quite cheap ... more blankets, or VERY expensive ... a warm body to sleep with :-)
 
  • Like
Reactions: Road and Baymax21

Road

Not into ranks, titles or points.
Launch Member

Advocate III

3,379
On the road in North America
First Name
Road
Last Name
Dude
Member #

6589

Hey y'all we're new to RTT life and wanted to find a way to mitigate condensation that isnt overly expensive. Any tip/tricks or gear advise would be greatly appreciated. Thanks!
.
I've used my hardshell RTT a ton over the last several years in all kinds of weather, and have found that simply keeping some air moving through has eliminated the need for any condensation mat under the foam mattress.

I think most people think they should zip their tents up tight at night. Which, especially if your tent's walls are made of a more non-breathable fabric, keeps all the moisture from your breath in. That then tends to condense on various surfaces in your tent if the outside temps are colder than inside.

I keep both end window covers zipped up only about 2/3rds and the entry door, which is covered by a small awning with sidewalls, with just the screen most nights. Then put my boots and jacket or whatever along the bottom of the doorway. Keeps all the air moving overhead, but not at mattress level. No problems with condensation.
.
 
  • Like
Reactions: FishinCrzy

FishinCrzy

Rank V

Advocate I

2,595
South Carolina, USA
First Name
Rob
Last Name
Duncan
Member #

19015

Service Branch
StateHazmatResponder
I had a problem with condensation underneath the mattress during cold weather. I don't think it had anything to do with tent ventilation per se since I leave plenty of ventilation because I like it cool being inside a warm bag. I think it was the warming of the mattress from body heat and the cold from the air outside on the floor causing moisture to form between. The higher humidity down here probably exacerbates the the problem. Probably not so much in the desert @Road :grin:. The moisture that can form inside the walls and ceiling can be from not enough ventilation and moisture from breathing, temperature differences, etc. I understand this since the Boy Scouts a hunnert years ago. I think we are dealing with two different situations.

At first, I was in denial that moisture under the mattress was a problem. Then I found the moisture after a couple of cool 30 - 40 degree nights. So, I purchased a not inexpensive anti-c mat that was made to fit and fold with my brand RTT. $130 or thereabouts. I did find some cheaper alternatives mentioned that were a type of filter mat? available from the hardware store that looked like it may work. That would require cutting and taping and there could still be an issue with folding it. Velcro might help hold it in place. I think mine came with Velcro? Anyway, to get the underneath the mattress ventilated so as no to trap moisture is a little expensive and it should be sold with the RTT, IMHO, because if one camps in cooler weather it may be a problem in my experience. Ventilation is a good thing! Funny how they never mention the under mattress moisture when selling you a RTT.
 
  • Like
Reactions: lhoffm4 and Road

Road

Not into ranks, titles or points.
Launch Member

Advocate III

3,379
On the road in North America
First Name
Road
Last Name
Dude
Member #

6589

I had a problem with condensation underneath the mattress during cold weather. I don't think it had anything to do with tent ventilation per se since I leave plenty of ventilation because I like it cool being inside a warm bag. I think it was the warming of the mattress from body heat and the cold from the air outside on the floor causing moisture to form between. The higher humidity down here probably exacerbates the the problem. Probably not so much in the desert @Road :grin:. The moisture that can form inside the walls and ceiling can be from not enough ventilation and moisture from breathing, temperature differences, etc. I understand this since the Boy Scouts a hunnert years ago. I think we are dealing with two different situations.

At first, I was in denial that moisture under the mattress was a problem. Then I found the moisture after a couple of cool 30 - 40 degree nights. So, I purchased a not inexpensive anti-c mat that was made to fit and fold with my brand RTT. $130 or thereabouts. I did find some cheaper alternatives mentioned that were a type of filter mat? available from the hardware store that looked like it may work. That would require cutting and taping and there could still be an issue with folding it. Velcro might help hold it in place. I think mine came with Velcro? Anyway, to get the underneath the mattress ventilated so as no to trap moisture is a little expensive and it should be sold with the RTT, IMHO, because if one camps in cooler weather it may be a problem in my experience. Ventilation is a good thing! Funny how they never mention the under mattress moisture when selling you a RTT.
.
May be a problem with some RTTs more than others. Perhaps, like I said, because of tent fabric and breathability. Some fabrics inherently breathe better, and some tent mfgs coat their fabrics with water repellency that diminishes breathability.

Here's a good explanation of tent fabrics:

.

I've used my RTT as many or more nights in the mountain forests of east Tennessee, humid swamps & bayous of southern Louisiana, wicked humid shores of the Gulf of Mexico, and New England lakesides in cool weather and freezing nights as I have in the desert.

My RTT is on a rack, with it's lower hard shell (fiberglas) exposed to the air, whether warm or cool. It may be a factor too, that the bottom is fiberglas in some RTTs and of a composite in others, and how one's sleep system is set up.

The bottom shell in mine has a thin lining, then the cheap 3" foam mattress, topped with a regular sheet, then a doubled-over comforter and a top sheet over that but under me. I also sleep in a wide lightweight sleep sack covered by an inexpensive Coleman bag--spread out, never zipped--topped by one to three jungle blankets depending on how cold, also spread. I doubt with my setup that much of my body heat is getting through to the shell, which certainly may be a factor in keeping condensation under the mattress at bay.

The only condensation I've ever experienced in all the places I've used it, and I've slept in it over 600 nights, was from my warm breath settling on the jungle blankets around my face when I first started using it, before I started ventilating more. Never any under the foam mattress.

Here's a whole page of links you might find helpful, @Baymax21 or anyone else reading this thread: Tent Fabric and Condensation

.
 
Last edited:

El-Dracho

Ambassador, Europe
Moderator
Member
Supporter
Investor

Inventor I

13,232
Lampertheim, Germany
First Name
Bjoern
Last Name
Eldracher
Member #

20111

Ham/GMRS Callsign
DO3BE
Hey y'all we're new to RTT life and wanted to find a way to mitigate condensation that isnt overly expensive. Any tip/tricks or gear advise would be greatly appreciated. Thanks!
According to the title of the topic, I assume that you are specifically looking for something for under the mattresses, right? When researching roof tents more intensively, I have seen a kind of mesh material that is available as mattress underlays. This provides better ventilation and thus the removal of moisture. Side effect is a certain insulation effect and a comfort gain especially with thinner mattresses. The material is available from the roll and can be cut individually. These mats are certainly also available in the U.S. at the outfitters, I guess.