Vapor Barrier Liners help me with gear choices

[KRS]

He all, Im looking for a little help on what I can use as a VBL for next winter. From what I’m seeing silnylon works well if used with a light base layer underneath. I would like to multi use my silnylon rain jacket (Luke’s ultralite jacket) for my upper body. For my legs I’m looking at the Oware 1/2 bag sleeping bag liner https://shop.bivysack.com/VBL-Half-Bag-Sleeping-Bag-Liner-SleepingBagLinerVBLHalf.htm?categoryId=-1 or buying/MYOG silnylon rain pants. As per my feet I’ve been looking at Sealskinz 100% waterproof socks or Hyperlite Stormsocks (neoprene). Does this all sound right? Im trying to either use what I have and get multi use out of each item at the same time.

[Bri W]

Ultimate Direction Deluge rain pants and jacket are non-breathable. I’ve been using those for my VBL stuff and rain gear in the warmer seasons. But there are no pit zips, so it’s harder to regulate temps. I have so far only used them for sleeping. In the winter I use RBH Design’s Lightning Bug pants and jacket (with lots of zips) and their hi-rise VBL socks for mostly sleeping and sometimes hiking depending on the temps. If you go with the half bag liner, I don’t think you’ll need VBL socks or pants. If Luke’s rain jacket is breathable in any way, then that’s technically not VBL and may not produce the same warmth effect. If you do go with socks like the Sealskinz, would they be for both hiking and sleeping? If just for sleeping, they’re probably fine, but my RBH socks are more lightweight than my DexShell waterproof socks. If the Sealskinz are anything like DexShell socks, they’re fairly thick and mildly have a wet-suit texture, so just keep that in mind if you plan on actually hiking in them. You can also just do the old bread bag trick to save money and weight. Or shove your feet in a pack liner bag, and there’s your multi-purpose gear. :)

[KRS]

Thanks for the info Bri. My Luke’s rain jacket is made from silnylon and I have seam sealed it. It has a water proof zipper and pit zips, but for the most part it does not breath at all. The 1/2 bag was the simplest cheapest option but I’m leaning more towards silnylon pants for the flexibility. Im guessing this would be very similar to your Ultimate Direction Deluge rain pants and jacket. As per the socks I thought I could get some more use mountain biking in the winter when my feet get really cold by using the Sealskins. I don’t know if the Sealskin socks would help, they are 100% waterproof so they should. Bread bags (i use turkey roasting bags) would work for sleeping but hiking they fall apart very quickly in my experience.

[Bri W]

Oh okay. If I had the capabilities of MYOG, I’d totally go down that route. But RBH did a stellar job on my pants and jacket (I had to have them sized XXS, and the Lightning Bug pants were a custom request), so I can’t recommend them enough. And the good news is you’ve got lots of time before next winter to test out different ideas. :)

[Edward John M]

I’ve used both systems and while not as versatile I prefer a full liner, a full liner doesn’t weigh much more and can be used as an emergency bivvy cover. If I had to choose between pants and socks and a half bag my experience says a half bag is better because you can crawl into the half bag while wearing your wet rain pants. Yes I have had to do this once and being able to get into something very warm and very quickly was important

LW bin liners make excellent VB bags

[KRS]

I have really never had a problem with my lower half getting cold for non sleeping situations, so wondering if a VBL for my lower half in my region is even worth it????? The half bag really makes the most sense to me, because my rain shell can also be a VBL and I already have it. The half bag is like 40 bucks and I wouldn’t need to buy rain paint, that I would not use otherwise. The Sealskin socks if bought might be used for other sports (mountain Biking in the winter) but really that has no part in my decision. Thanks Edward for your point of view and thanks Bri for yours, both are really helping to make my decision. Ya I have till next winter but time fly’s LOL!

[KRS]

On a side note would a wind breaker like a Patagonia Houdini and Montbell Dynamo wind pants work as a VBL? I know the breath a little but in a pinch would they work good enough?

[Edward John M]

To work well a VB really needs to be impermeable, but having said that I have used a partial VB to great effect several times. I have a Tyvek bivvy cover which I have used as a liner in the past [ mentioned several times in other posts] and I have just bought a reflective SOL breathable bivvy to use as a deep winter liner, as much as it becomes a partial VB as for the reflective warming benefit that I think is marginal

The less breathable the garment the more it will act as a partial VB

The half bag will be warmer and trash bag experimentation seems to be called for here

[Eric Blumensaadt]

The sleeping bag VBL idea is to keep all perspiration out of the bag. This requires a full bag liner, not VBL clothing which “leaks sweat from many places.

I’ve talked to a Canadian who was in their Joint Forces (Spec. Forces) and he said they use this full bag VBL setup in extreme cold from near sub zero (F.) to -40 C.

Theirs evidently has a tie on the foot of the VBL bag to tie into the inside of the foot of the winter sleeping bag. He says this is essential to keep the VBL from bunching up when in use. I dunno it they use a military VBL bag or something made for them by someone like Arc Teryx.

[R]

2 things to add here.

As has already been more or less said, a VBL does two things: it reduces heat loss due to insensible perspiration; it keeps said perspiration from entering your sleep insulation.  The former effect is relevant at all temperatures.  The latter is only relevant in cold enough conditions for the dew point to occur inside your insulation.  This become more important on long, cold trips where opportunities to dry your insulation are further apart.

Given this, a partial VBL helps with both, but not as much as a ‘full’ coverage with an impermeable membrane. (I put full in quotes as any garment system will leak at the waist and ankles, and people generally skip their head, which loses a fair bit of moisture given it’s circulation and temperature.)  If you’re less worried about moisture in your insulation, you’ll probably find more value in a partial VBL.

The other thing is that if you use a bag liner rather than a suit, you probably don’t want to wear anything more than a base layer when you sleep.  If you do, it will be inside the VBL and when you crawl out in the morning (or the middle of the night) it will be saturated with humidity which will promptly condense inside the insulation.  If you’re wearing a rain shell, pants and socks, you can pile on everything else you might have had on at dinner, on top if it before you crawl in to bed, and it will all be dry in the morning.

Between not carrying single-use VBL pants, vs. getting to add your lower body insulation to your sleep system, the winner on weight may be a function of your budget for the pants.  Cuben/DCF is mighty light.

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