Rab Vapor Barrier Socks Review

Mountaineering Boot Layering System

If you’re used to thinking about layering in winter, forget what you know, because vapor barrier clothing helps you stay warm and dry in a radically different way than conventional layering approaches.

Vapor barrier clothing is not breathable and is normally worn next to the skin or over a thin wicking layer. It’s designed to prevent perspiration from wicking up through your layering system, so it’s good on multi-day trips when it is very cold and you have a limited ability to dry wet clothing. It’s very counter-intuitive, but it works surprisingly well.

The most common applications of vapor barrier clothing are in boots and winter sleeping bags, where perspiration can significantly degrade the insulation value of down or synthetic fill, particularly in cold temperatures on multi-day trips. Sleeping bag maker, Western Mountaineering, makes a vapor barrier liner called the HotSac VBL, which is used for this purpose. I used to own one and found it a bit uncomfortable, but some people swear by them.

Vapor Barrier Socks

I started wearing vapor barrier socks this winter as an experiment to see if they’d help keep my mountaineering boot liners dry on day hikes and winter backpacking trips. Although I like my Scarpa Omega double plastic boots a lot, I’ve been thinking about buying a second, lighter weight pair of mountaineering boots without a removable liner that has a little more ankle flex and fit better than a plastic boot.  I’m hesitant to wear a boot like this though for overnights or cold-weather trips, however, because I know that I’ll soak them with perspiration; hence the desire to try a vapor barrier sock system that can keep them dry for multi-day trips.

For my winter boot system (see photo above), I’m using a pair of  Rab Vapor Barrier Socks made of silnylon, which are seam taped to prevent moisture from leaking out. I wear them over a very slippery black nylon dress sock (gold toes) and then cover them with an expedition wool sock from REI. Next, my foot goes into the heat-molded foam Intuition liner that came with my mountaineering boots and then into my plastic Scarpa Omegas. After the boot is on, I put on a set of Hillsound gaiters over my ankles and calves to keep snow from wetting my socks and to provide insulation for my calves.

Integral Designs Vapor Barrier Socks
Rab Vapor Barrier Socks

Before I used vapor barrier socks, I’d completely soak out the liner socks, wool socks, and Intuition liners with perspiration on winter day hikes. On multi-day backpacking trips, that meant sleeping with my liners in my sleeping bag at night to keep them from freezing and to dry them out. As you can imagine, this is a somewhat unpleasant thing to do, even in a big -25 degree down sleeping bag.

But after I added vapor barrier socks to my boot layering system, the outside of the vapor barrier sock, the wool sock and the foam Intuition liner come out of my boots bone dry at the end of a hike. It’s a pretty remarkable difference. So far, I’ve done a dozen major winter hikes using these Rab VB socks, with temperatures ranging from 10 below zero to about 20 degrees Fahrenheit, and I’m hooked. It’s really convenient not to have to worry so much about drying my socks and liners after a hike or on an overnight trip.

Rab Vapor Barrier Socks

There’s nothing fancy about the Rab Vapor Barrier socks I’m using. They’re just made of silnylon and seam-taped to prevent moisture from escaping. They have a piece of elastic sewn in that holds the fabric flush with your leg at the shin and an additional piece of shock cord a bit higher up. Some people I know use bread bags to achieve the same effect, but I like the robustness of the VB socks, so far.

How does my foot feel inside the vapor barrier sock? It doesn’t feel wet. If anything, it feels like I’m wearing a sock that’s slightly too big over the black dress socks I use for my liner layer, but it’s not that annoying, and I quickly forget about it once I start hiking.

When I strip down after a hike, the black dress liner sock comes out of my boot slightly damp, but not soaking wet as one might expect. This has convinced me that my foot is really sweating less overall because the inside of the vapor barrier sock is so humid.

Moreover, when I pull the damp liner off my foot, the skin is not wrinkled and prune-like but looks absolutely normal. Nor do my feet smell terribly bad, but the vapor barriers liners do pick up an unpleasant odor after a few days if not washed or rinsed out between hikes.

Warmth-wise, I haven’t really noticed any difference between wearing a vapor barrier sock and hiking without one. That’s not that surprising since my mountaineering boots are rated for -30 degree temperatures and I haven’t been in that kind of weather this year.


Even though I’ve owned these Rab Vapor Barrier socks for a few years, this was really the first winter that I’ve started using them on a consistent basis. Honestly, they work great and I plan to continue wearing them this winter for all of my hikes and overnight trips.

If you’re interested in learning more about vapor barrier clothing and lightweight gear for mountaineering, one of the best sources I’ve read is Mark Twight’s Extreme Alpinism: Climbing Light, Fast, and High.

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  1. I always use Integral Designs VBL socks during winter, with single-skin boots, and always have toasty feet. I think one thing that cannot be stressed enough though (if you’re on a multi-day trip) is that you *must* clean and dry your feet thoroughly and get them into clean socks each night – otherwise trench foot will set in…

    • As usual, great mountaineering advice Chris. Thanks!

    • Chris, do you wear the VBL socks directly on skin or as Phil does with a thin sock as the first layer?
      Do you take a sock per day or do you swap back and forth between two pairs to let one pair air out each day?

      Phil, how do you find the sizing? I like my socks very tight on my foot (so I generally size “down”). Do you know of a local to Boston store that has them to try on?

      On our sub-0 hike in January I had just a pair of DarnTough wool socks and my goretex boots, as long as we kept moving my feet were quite warm, but by the end of our rest breaks my toes were getting quite cold, so I’m looking to find a system to solve that.


      • They fit like clown shoes, but it doesn’t really matter because they are so slippery. There’s no rubbing. No one sells these in retail…it’s not a high volume item. Unfortunately, there’s not much you can do about cold toes except keep moving or add a lot of extra insulation like in a mountaineering boot. That’s in part why fast transitions are required in winter backpacking.Movement = warmth.

      • Steve – I wear a thin pair of wool socks as a first layer, and dry them out in my sleeping bag each night. For a climb of a couple of days I just take one pair, anything longer then 2 or more pairs. I haven’t found any adverse effects on my feet, and tent partners have never complained, so I think it’s OK! But as I mentioned above, scrupulous hygiene each evening is key – wash them, dry them, get them into clean socks (I usually just use my thick outer socks) – and I pack a little bottle of biodegradable soap if I’m going out for more than a few days.

        To reiterate Phil’s points on sizing: the socks are huge. But they get squished between the inner and outer socks, so it’s not a problem. You might be concerned about the consequent wrinkles causing blisters, but don’t be – the VBL sock creates a near-frictionless layer. I’ve never had blisters with my VBLs.

        I did a couple of seasons with supermarket plastic bags on my feet before I bought my Integral Designs socks. Works perfectly well – you might want to give that a try to see how you get along with the whole concept.

        Hope that helps!

      • I have an issue with socks, as a concept in general, so it’s doubly tricky for me to find a system that works for me. part of it is I have warm feet in general (I wear sandals in winter), so I need to find a method that isn’t too warm. though it sounds like toe colds when not moving may not be a “curable” issue.

        I’ve heard ham bags work really well and are cheap. I’m ok with the VBL concept, just a matter of finding the best method for me. i’ll have to try the ham bags and see what VBL socks can offer me.

        now I just need a free weekend to get into the woods, February has been swamped for me!

        thanks guys!

  2. Would love to try the integral designs socks, I’ve done trips with a plastic bag and the result really surprised me! Will move on to VB clothing.. Time will tell if I’ll continue with plastic bags or if I move on to a myog solution. Think ID socks are hard to come by in Scandinavia…

    Good article, might just be me searching the subject alot right now, but it seems VB use is growing at the moment.

    • I think it’s an easy enough myog project. Just need the two sides to a sock (pattern) and some seam tape. I thought I saw something online about someone making them out of cuben but silnylon is really all you need.

      • Yes, I’ve seen a thread about it on BLP too, if my memory serves me correct – which it usually don”t – it was actually Will’s socks. They were made up of three pieces, which I think would be a bit more ergonomic. Then again, that’s one more seam to seal, plus possible chafing point.
        But yes, it would be a nice little afternoon project. Definitely silnylon, I’ll likely have some leftovers from my next project. Plus I’ve lately started to think silnylon might often be better then cuben – atleast if one is on a budget. It’s only socks. :)

        Again, thanks for bringing up the subject.

  3. I use the plastic bags the newspaper is delivered in. Works well and the bags are pretty durable.

  4. MEC is a great place to buy gear.

  5. Thanks to your emphasizing that the primary benefit of VBLs is to keep your footwear dry on an *overnight* hike, I get it now. I only tried them on long winter all-day hikes before, and found the benefits to be marginal at best. But my shoes and outer socks DID stay dry then, so this is definitely something that I’ll have to re-visit on an overnighter! But since we have no winter to speak of this year in NY, I’ll likely have to wait till next year for the field trial .. the way the weather has been going down here, I’m about ready to break out the hiking sandals again :)

  6. Has anyone been up to the October Moutntain Shelter on the A.T. Lately? Planning on an overnight Monday/Teusday. (3/5-3/6) Just looking for some info on trail conditions. Hopefully there is some snow.

  7. Hi, can you use Rab VB socks as waterproof socks when hiking in trailer shoes ?

  8. Great article. I got my first pair of VB socks 30 years ago from Ragged Mountain Equipment back then I was concerned with my fleece-lined winter boots getting wet. Today I wear them with my alpine and x-country ski boots. I wear a liner sock then the VB Socks. I think they keep my feet warmer.

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