Vapor barriers -what is your opinion?

[BillyBob58]

Update on this...total let down on my past two trips! I thought these Rab socks were good quality, but apparently the seam tape leaks. My socks were very damp from sweat. So before the next trip I sealed the outside with a generous coating of silicone. Still failed! I guess the material itself is letting sweat through. When I fill them with water and squeeze, I only see a few spots along the seam with tiny leaks. But one sock even has two jets of water spraying out, so I'll try to seal those. But overall, I may have to give up on these.

Now on to the sleeping arrangement. The last two trips I slept down to 0° or lower were frost fests. The frost bib caught a lot of vapor and kept my TQ dry around my neck, but there was plenty coming out between my hammock and UQ. Most was at the foot end; warm moist air leaking out and refreezing on the outside of my hammock. Everything was cinched nice and clean but there's no way to make this "air tight". My last trip was so frosty by the second morning that I even felt wetness inside the TQ as well. Trip's over at that point. Luckily I slept very well on both trips, but another night would be out of the question.

I may entertain a VB liner in my quilt, but I really don't want to. I can handle my feet, but my whole body while sleeping doesn't sound fun.

Well that is a bummer! Hate to hear it. I have never put my SWL VB socks through any hard duty- a few 30 minute hikes, but mostly I just sleep in them. So I don't know how they might hold up to what you are dong. But I am very surprised to hear that- even with a few leaky spots, enough got through to wet your socks. And that is supposed to be high quality gear! I guess yu could boost them with bread sacks, or even replace them with the same.

OneClick, as an experienced and sane member here(I know I might be considered a bit on the outer edge around here sometimes, and my ideas/opinions are not always the same as mainstream), I just want to thank you for verifying some of what I have always said about our breathable gear, once the dew point gets inside the quilt, or even the surface of the quilt.

Just like my friends experience that I have mentioned here before- and all without any eternal moisture(in all cases) getting past the tarp and on the quilts. At least I am assuming that is also your case? If you felt moisture(or even if you didn't) inside the quilt, then I must also assume- just like my friend's experience on 2 different wee long trips- you also lost loft. So now you likely have evaporative cooling going on inside your insulation, as well as next to your skin, plus you insulation is not as thick as it used to be. Pack that up for a few more nights, unless you had plenty of sunshine for drying, and you might have had trouble. I think you agree.

Also, if that happened, it would appear your breathable gear took a break from breathing, right? And of course, all breathable gear does that when the dew point moves inside the quilt or clothing. It is the most basic science. Is anything more breathable than fleece or air? But if your breath hits either the fleece frost bib while sleeping or the cold air in front of your face while walking, does it not condense into liquid? Of course it does. When warm body vapor contacts a cold enough material, or even just cold enough air, it condenses into liquid, every time. If your tarp was breathable, I'm pretty sure moisture would still condense on your tarp. I have gone outside to find an unoccupied hammock and quilts and underside of my tarp coated with frost, I suppose the vapor was coming up from the wet ground under them, I don't know.

The only reason people are not more aware of this is because their trips are short, their gear is rated warmer than needed, and they are not measuring loft or weighing quilts after every night. And it probably also helps when there is plenty of sunshine and/or folks don't have to pack up a damp quilt every morning.

But, if you are going to maybe add VBs to your sleep gear- I'll just say my personal pref is clothing over a separate bag liner. First, it is multi-purpose, it can be worn around camp or even hiking if cold enough. You might even be able to replace a layer with it, depending on how many layers you have, so little or no weight increase. And, if you use TQs because you hate bags, a bag liner is sort of a step back towards a bag.

But, thank you for pointing out your experience which is pretty much as I would expect, sooner or later. Actually, always sooner, but most of the time not soon enough to be noticed unless we weigh quilts or measure loft.

[OneClick]

My tarp was set to block most wind and certainly all snow. I left one end completely open and had a good 6" gap all down the center of the other side. Decent air flow, but nearly dead calm with no wind at night.

Loft...WAY down after getting damp. When I was packing up Sunday that 0°+2oz top quilt felt like a 40° quilt! Even after lying them in the jeep on the way home for 4 hours, they were wet once I got home.

The inside of my tarp wasn't frosty as it is many times, so I think my bib caught a lot of breath.

I think it's obvious without the arrows, but they show the foot end with frost (nothing new, just more than usual). Warm body heat escaping. And no, my UQ wasn't set this loose overnight. I just had it adjusted more for airing out at this point.



And the bib (still liquid near my mouth, frozen beyond an inch or two)



Would an underquilt protector prevent this? I always figured that would just make it worse, trapping LIQUID instead of letting it freeze. But maybe not? If it would freeze on the UQP instead, that would be nice so I could just shake that off in the morning. But I don't think anything other than a VBL would solve the wetness.

I wish someone made a nice-fitting, quality VB suit. I'm thinking the Tyvek stuff hazmat guys wear (but most of those breathe). Sounds stupid, but simple.

[BillyBob58]

My tarp was set to block most wind and certainly all snow. I left one end completely open and had a good 6" gap all down the center of the other side. Decent air flow, but nearly dead calm with no wind at night.

Loft...WAY down after getting damp. When I was packing up Sunday that 0°+2oz top quilt felt like a 40° quilt! Even after lying them in the jeep on the way home for 4 hours, they were wet once I got home.

The inside of my tarp wasn't frosty as it is many times, so I think my bib caught a lot of breath.

I think it's obvious without the arrows, but they show the foot end with frost (nothing new, just more than usual). Warm body heat escaping. And no, my UQ wasn't set this loose overnight. I just had it adjusted more for airing out at this point.



And the bib (still liquid near my mouth, frozen beyond an inch or two)



Would an underquilt protector prevent this? I always figured that would just make it worse, trapping LIQUID instead of letting it freeze. But maybe not? If it would freeze on the UQP instead, that would be nice so I could just shake that off in the morning. But I don't think anything other than a VBL would solve the wetness.

I wish someone made a nice-fitting, quality VB suit. I'm thinking the Tyvek stuff hazmat guys wear (but most of those breathe). Sounds stupid, but simple.

If this was all body vapor condensing when it hits the dew point, I doubt an UQP would have helped much, although maybe. It would move the dew point out another small fraction, possibly causing at least some of the condensation to move to the outside of the shell. Or, not. Also as you mention: some folks complain of condensation problems with UQPs. But, it is possible, depending on conditions, it might move the dew point a bit further out.

The main benefit of UQPs for me is protection from wind and outside moisture. Unless of course there was some added insulation inside that UQP, which would move the dew point even further out, possibly out of your quilt and all in the added insulation. But that seems like a lot of trouble, bulk and weight just to deal with condensation of what is apparently body vapor.

Have you checked out Stephenson's Warmlight? Not something like Rab that you would want to wear out on the town, but very functional, and though I think they have gone up a lot in price since I last did business with them, still a lot cheaper than most. I think. As for looks, if worn under other layers, no one is going to see them anyway.
https://www.warmlite.com/product-cat...rier-clothing/

[cmc4free]

Not something that you would want to wear out on the town...

I don't know... Those look pretty chic to me!

[BillyBob58]

I don't know... Those look pretty chic to me!

I call mine my duct tape shirt! I have not looked close to see if they have spoofed them up some.

[cmc4free]

wIMG_7432-444x444.jpg

"No sweat" pants

[BillyBob58]

Update on this...total let down on my past two trips! I thought these Rab socks were good quality, but apparently the seam tape leaks. My socks were very damp from sweat. So before the next trip I sealed the outside with a generous coating of silicone. Still failed! I guess the material itself is letting sweat through. When I fill them with water and squeeze, I only see a few spots along the seam with tiny leaks. But one sock even has two jets of water spraying out, so I'll try to seal those. But overall, I may have to give up on these......................

Another thought on these socks. I am really surprised your socks got soaked. Even if there is some leaking going on at the seems or a small hole, it is not like these are trying to keep out lots of water under pressure. Well, except I guess some pressure right under your feet. But I just wouldn't have thought it would take something highly waterproof just to keep vapor or even outright sweat out of your socks. But, apparently it takes more than i thought. Especially when it comes to sweat under pressure from standing on the bottom layer of the socks.

[BillyBob58]

wIMG_7432-444x444.jpg

"No sweat" pants

These pants should attract the ladies big time!

[OneClick]

Another thought on these socks. I am really surprised your socks got soaked. Even if there is some leaking going on at the seems or a small hole, it is not like these are trying to keep out lots of water under pressure. Well, except I guess some pressure right under your feet. But I just wouldn't have thought it would take something highly waterproof just to keep vapor or even outright sweat out of your socks. But, apparently it takes more than i thought. Especially when it comes to sweat under pressure from standing on the bottom layer of the socks.

I think that's it. My 170lb plus the constant twisting and stomping of a 5hr hike. It must drive the moisture through. I tried the 100% effective oven bags, but the bulk and shape were pretty uncomfortable.

I looked at the Stephensons stuff, but they don't seem right. More of a dressy fit. A collar? I just need a nice slim, functional fit.

[Groundskeeper]

Vapor Barrier experimentation

I have been reading the vapor barrier discussions both past and present with a morbid fascination. When I first came across it my thoughts were “What kind of idiot wears a sweat suit in the winter?” Yet, as my reading continued there were nuggets of information that slowly sunk in. BillyBob58 is nothing if not persistent. There was anecdotal evidence, there was use of VB’s by Andrew Skurka. Maybe I was missing something.

Finally while reading this thread it finally sunk in. It is the evaporative cooling element that got me to thinking this could work. Sure, containing the moisture keeps your insulation dry, but what I saw as a great value was stopping evaporative cooling. I think the reason it took so long to understand this was that I never thought of evaporative cooling in a cold environment. But the laws of physics do not suspend there self just because it gets cold.

Since we had a nice cold front rolling in, tonight was the night to test the theory. Since no sane person actually owns vapor barrier clothing, I made due with Frogg Toggs top and bottom. My base layer was LL Bean long silk underwear, then the Frogg Toggs. I wore a cotton/polyester blend cargo pants, an 80% wool sweater from Goodwill, and a Gerry 650 fill down puffy. On my feet I decided that since I have two of them, I can conduct a controlled test. On my right foot I wore a Shower Pass waterproof sock with a Heavy Wigwam wool sock over that. On the left foot was a thin wool sock covered by the other Wigwam sock. On my head I wore the Frogg Toggs hood and a Carhart cap/balaclava.

My sleeping rig is a JRB Bear Mountain Bridge hammock, JRB High Sierra Sniveller TQ (5*), Greylock 4 UQ (0*), and for good measure a Thermarest pad (R-3.4) in the sleeve of the hammock. Because it was windy and there were light flurries at the time I was setting up I also used the 2QZQ under quilt protector. All this was covered by a 10 x 10 Etowah tarp with custom panel pulls.

The experiment started at 7pm, 21 degrees. I set up camp and built a small fire. To ensure I had some overnight pee breaks, I had a few adult beverages. During the camp fire phase, the true value of the VB system became apparent. Normally at that temperature, and getting colder, I would have worn another layer. Usually a 200 or 300 weight fleece jacket I have or another down coat. With the VB system I didn’t need it. This means that on a backpacking trip I can leave that extra layer of bulk and weight at home and still be quite comfortable. I also noticed that I did not get a cold butt while hanging around the fire like I usually do. So far, I was impressed.

At last it was time to hit the hammock. By this time, it was down to 17 degrees. I took off the puffy but wore everything else. I also added a rather skimpy down hood that has proven effective for sleeping in the past. I settled in and went to sleep. By 1:30am I had two pee breaks and I was no colder doing it than any other night. When I got up in the morning to get ready for work it was 9 degrees, my new personal best, and other than my nose and left foot, everything was warm and dry. No frost, but the balaclava and opening of the down hood were rather soggy. The only things that got cold were the areas NOT covered by vapor barrier: My face (really my nose) and my left foot (which, as you may recall, was only in wool socks, not the waterproof VB sock).

BillyBob58, I hereby apologize for anything I may or may not have muttered about your intelligence and good sense regarding vapor barriers. Now I will be investing in some of those sexy Warmlite VB clothes.

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Vapor Barrier (2).jpg

It got too cold for my outdoor thermometer so I got a reading from my indoor thermometer.
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