DCF Single Wall Tent Condensation…

[bradmacmt]

I’m curious to hear thoughts and experience about condensation with single wall DCF tents.

In 2009 or 2010 I got a TT Rainbow. No matter where I used it I experienced significant condensation. I eventually sold it. However, loving the design (I don’t do trekking poles), I bought the DCF version in 2022. Though I haven’t used it a lot, I have never had one night of condensation.

Reviews of the Rainbow Li aren’t plentiful, but  there are plenty for the Aeon Li and Pro Trail Li. Both have accounts of condensation, but in my rather unscientific analysis, it seems to me I’ve read more about condensation in the Pro Trail Li.

I guess my question (and wondering out loud) is do you think the taller DCF pyramid-ish tents like the Rainbow and Aeon move moisture more efficiently because of their shapes? As a builder, I think of a chimney… warm air rises most efficiently straight up, rather than at an angle. The greater the angle to the venting point (Pro Trail) the less efficient the “chimney effect?” Obviously interior volume also has to play into it too. I’m guessing, all things being equal, a smaller version of the Aeon Li or Rainbow Li would be more prone to condensation?

Anyway, curious to hear your experience and thoughts. Also, I don’t mean to limit this conversation to Tarptent DCF creations. Durston, Zpacks, Hyperlite, and more make excellent DCF shelters, I’m just most familiar with TT so that’s where my conversation starts.

[Todd T]

Maybe DCF is a little less prone to condensation than sil{nylon,poly} because it’s somewhat transparent to infrared radiation to/from the night sky?  (Meaning the fly itself wouldn’t get quite as cold.)  Tent shape can make a difference too because of differing view factors between tent surfaces and the sky.  Just thinking out loud.

[Jerry Adams]

Yeah, I thought the same thing, based on see seeber”s data DCF is transparent to IR so maybe it doesn’t get as cold as a nylon or polyester tent.  If the DCF isn’t as cold, water won’t condense on it as much

I was thinking DCF will make you colder inside the tent, but maybe reduced condensation is the other side of the coin

Yeah, higher peak might result in better air flow so less condensation.  If you leave the door open that also helps

[Dan]

I’ve spent many nights in single wall DCF tents, and there’s no shortage of condensation unless you work hard to facilitate ventilation and airflow. I usually try to pitch the tent fairly high and leave the fly door open if possible. On the bright side, it’s a pretty hydrophobic material and if you pitch it well, it stays taut, so condensation often runs down as designed. Personally, the benefits of these tents outweigh some condensation, which I can live with.

[jscott]

single wall DCF tents have to pitch with a lot of ventilation to avoid condensation, and so tend to be cold.

So…get the Notch Li .

[Dan @ Durston Gear]

The primary condensation difference between single and double wall is whether they have that barrier layer, as condensation can form in either type to roughly similar extents. So it is not so much than singlewall tents get more condensation, as that it is easier to touch.

For venting, if the moisture source is ‘internal’ (e.g. breathing, cooking) then venting can help, whereas if it is ‘external’ (e.g. cold foggy air) then venting just exchanges wet air for other wet air and doesn’t do much.

Whether a pyramid shape helps to ‘chimney’ the moist air out, is an interesting question. Upon quick thought, it seems like it could help, but I also suspect vent size and the opening overhang are larger factors. If a vent has a lot of overhang so air has to go up to the vent, and then drop down below the top flap to escape, that is going to limit the natural air movement a lot. I’m also not sure to what extend the warmth of a human is sufficient to really create a chimney effect. In cold conditions you’d have a very insulating bag that would keep a lot of heat in. The heat that does escape would want to rise, but it might be a weak enough effect that it’s not that meaningful. Hard to say.

[jscott]

My point about double wall tents wasn’t that condensation is less in a double wall. Rather, with a double wall, condensation is less of an issue overnight, because the inner wall remains dry and keeps moisture from dripping onto the bag or quilt. And double walls are warmer, overall.

[bradmacmt]

I think we’ve all been at this long enough to understand the positives of double wall tents… this thread is about single wall DCF tents.

[Bill in Roswell]

I have a Pro trail Li and an older silnylon version. The sil version has a loop tab on the centerline of the door panel at the bottom. That allows me to set a cord to stake point, so half the door can remain open. Unless it’s raining, I leave the door half open. As my head is next to the mesh door, there is plenty of ventilation. However, in high humidity with zero wind, condensation can happen. I rigged a similar setup on the Li – never seen condensation on it. But I’ve not had the Li in a situation where condensation would form – so far. In foggy weather things are going to get damp.

[jscott]

“I have a Pro trail Li and an older silnylon version. ”

sorry, bill, according to Brad this topic is not allowed. this thread is about DCF single wall tents only…according to Brad.

Dan Durston’s post above is also disallowed…according to Brad.

 

[bradmacmt]

“I have a Pro trail Li and an older silnylon version. ”

sorry, bill, according to Brad this topic is not allowed. this thread is about DCF single wall tents only…according to Brad.

Dan Durston’s post above is also disallowed…according to Brad.

 

single wall DCF tents have to pitch with a lot of ventilation to avoid condensation, and so tend to be cold.

So…get the Notch Li .

 

@jscott You need to actually read – Dan was responding to your post pushing the DW Notch. You can’t seem to help yourself touting a double wall tent that requires two trekking poles when this thread is clearly about single wall dcf tents and ventilation – I also clearly said I don’t do trekking poles. My response regarding DW tents was directed at you, not Dan.

 

[bradmacmt]

I have a Pro trail Li and an older silnylon version. The sil version has a loop tab on the centerline of the door panel at the bottom. That allows me to set a cord to stake point, so half the door can remain open. Unless it’s raining, I leave the door half open. As my head is next to the mesh door, there is plenty of ventilation. However, in high humidity with zero wind, condensation can happen. I rigged a similar setup on the Li – never seen condensation on it. But I’ve not had the Li in a situation where condensation would form – so far. In foggy weather things are going to get damp.

Thanks Bill. The ProTrail Li is one that had my eye for a while. Front entry isn’t a deal killer for me. However, this morning I bought an Aeon Li and carbon pole since I’ve never had a Mid and thought at 20% it was worth a try. I do love my Rainbow Li though… it’s basically a perfect tent for me.

[bradmacmt]

Back to the idea of the “chimney effect.” Years ago I built a custom home for a gentleman that wanted a cigar & whiskey room off the main house. The architect added a shed roofed room off the main body of the house. The client insisted on a wood-burning fireplace for this room. While understandable, I knew it was going to be a problem. Sure enough, the fireplace wouldn’t draw, exhibiting what we call “backdraft.”

The chimney was well below the main ridge of the house, and the prevailing NW winds swept down and across the chimney, making it impossible for it to draw properly (see drawing). I’d anticipated the problem however, and had power ready at the chimney. We installed a blower motor, and it drew. However, that’s a workaround for what is plainly a bad design.

Obviously a tent is not the same as a house with a chimney, but I do wonder about similarities… how do vents (the tent chimney) draw in relation to the tent ridge and prevailing wind? A human body in a sleeping bag generates some heat, but I wonder how much effect this has on pushing out the vapor your body and breathing makes. And of course environmental conditions alter everything accordingly.

Regardless, I just don’t think the value of good venting at a tent’s ridge/apex can be overstated and am always surprised by tents that omit them.

[DirtNap]

On a very wet and snowy August week last year in the Winds, I had one of Dan’s Gen 1 X Mid Pros. It’s was extremely wet and wild no matter what we did. But when I say wet, I mean five days straight of deluge crescendoing with a 4 inch blizzard. So any single wall structure would have been a water park. We kept reasonable dry by dapping with pack towels and toying with higher pitches etc but it was an effort. The tent did a really good job of directing drips to the lower mesh and not directly on top of us. Nature of the single wall beast.

[Jerry Adams]

The situation when a DCF tent might have less condensation is if the sky is clear and you have a lot of exposure to it, like not too many trees.

[Terran Terran]

A good shelf will mostly prevent downdraft. A chimney pot might have been a fix. Regardless you’re talking about a fair amount of heat creating the updraft. Unless your vents are at the very top, you’d still have condensation at the peak. The hot air would have to work its way back down and out the vent.

[Philip Tschersich]

I’m surprised there isn’t more mention of the characteristics of the fabrics themselves.

Silicone impregnated fabrics are highly hydrophobic. Water droplets are more likely to bead on the surface of them. Think ‘effective DWR’. Condensation in calm conditions manifests as a lawn of tiny water droplets. Picture peas on a plate.

DCF is non-absorptive (assuming the mylar is not compromised) but not really hydrophobic. Condensation tends to be more of a spread-out film of water on the surface of the fabric.

In my experience, the total amount of condensate sitting on the surface of siliconized fabrics is larger than on the surface of DCF given the same environmental conditions. The larger volume of condensate on the siliconized fabrics means it takes longer/more energy to evaporate and the user will get wetter when making contact with the inside of the shelter fabric. This also leads to ‘misting’ when the fabric shakes.

I’m DCF all the way.

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