As far as I can tell the Fuera smock is made of the same stuff as the outer part of the Paramo coats (hence why washing the Fuera in TX Direct gives it a waterproof coating).

I always thought that the lining of the coats (or Tiaga fleece) moves (pumps??) the water in one direction... inside-to-out.
But, if you press on the coat it may force it back (lean on something in a Paramo coat and you feel the damp).

In the same way the reversible tops (Mountain Shirt/Explorer Shirt) move the water from fleecy side to smooth side. Press on the outside, and the water can be forced back.

If I spray water on a typical wicking T-shirt it just stays there... I need body heat to force it out. Paramo tops just move it to the smooth side.

"made of the same stuff as the outer part of the Paramo coats " - yep. it feels and looks the smae.

"But, if you press on the coat it may force it back (lean on something in a Paramo coat and you feel the damp)." - no. you'll feel the cold of whatever you lean against and hence have the impression that it's wet.  it is extremely difficult to force water the wrong way through the pump liner in normal wear (i.e. outside to inside) - the only way i've managed it is to scrunch the fabric up around a large blob of water and squeeze hard.

"pump" is just marketing speak for capilliary action because i guess it sounds so much sexier. it doesn't "pump".  you have to try to convince people who just can't get their heads around the concept that waterproof means staying dry. and something doesn't have to be water impermeable to keep you dry.

"In the same way the reversible tops (Mountain Shirt/Explorer Shirt) move the water from fleecy side to smooth side. Press on the outside, and the water can be forced back." yes. smooth side to fluffy side. but if you were to proof one then the capilliary action is reversed and water is moved from the smooth to the fluffy side(but bear in mind this is an "added benefit" of the jackets and not really how it does most of its job). the fluffy side has a huge surface area and the water surface tension prevents it being pushed back onto the  smooth side. the huge surface area is what makes it so great at wicking in the tops/towels.

the main paramo function is letting any internal moisture evaporate and pass freely through the liner. once past the liner, it will either continue on it's way out through the outer shell, or it will condense on the fluffy side. any water that permeates the shell will be trapped on the fluffy layer until it either evaporates back out again or if enough, runs down inside and out the bottom of the jacket/sleeve. so condensation is never on the inside of the jacket. for the liner to "pump" it would have to be in contact with moisture and with there loose styling that just isn't going to happen.

whilst the mountain tops look the same as the liner we don't actually know if it is the same stuff, and naturally, paramo keep very schtum on the subject.

kalamazoo,

donning my SuperPedant cloak and externally-worn y-fronts, I have to say that no 'waterproof' fabric could be 'breathable' by your definition. 'Breathability' is really vapour permeability; and water vapour is water after all!

Matt,

I presume your question was retorical, but it's not always as simple as that. In extreme cold - the domain of the vapour barrier - I would rather that my skin surface was wet and that my insulation layer was dry. With P*****, it's preferable for the skin to be dry and for (at least part of) the insulation layer formed by the pump-liner to be wet! In one case I'd want a waterproof (vbl) and in the other I'd want a stay-dry-system!

Matt, the usual point talked about for VBLs is well south of temperatures typically experienced in the UK.  From Needle Sports' blurb on the Rab sleeping bag VBL, "A Vapour Barrier Liner is a non-breathable fully taped liner to line the inside of your sleeping bag with and so stop water from your wet clothes soaking the down. This makes you quite sweaty and guarantees an uncomfortable night but a dry sleeping bag, essential if you are staying at altitude for any length of time in a situation where you are unable to dry your bag out."

Altitude listed there, but I imagine lowish in Alaska in a cold spell would be a similar sort of game. We're looking at constant periods well below zero in either case.  My memory suggests -20C or so, but that's not checking any sources and could be off.

Pete. 

Hi Matt,

Most of my information regarding VB kit is second hand; I haven't tried it myself but have been in conditions where I think it would have been justified. I am quite often in Canada in winter and have often been running in -15C to -26C (plus windchill) conditions. It was here that I started to notice the limitations in my winter running kit. My highly permeable Pertex windshirt & trousers were literally starting to freeze solid within an hour. Perspiration was passing well through my baselayer(s) but was meeting the Pertex, condensing and freezing. I suspect it wouldn't have been long before the frost continued inwards - if I hadn't been chucking out about 800-1000Watts myself, I would have got very very cold. But I was running along a creek in beside the Ontario suburbs within easy reach of residential areas, so wasn't at too much risk.

I have read many US army guidelines, and they start using Vapour Barrier boots (aka Mickey Mouse boots) at temperatures below OF / -18C. This makes sense to me as extremities are very hard to keep warm and leather boots won't stay breathable anyway once they start to freeze. Stephenson's Warmlite are evangelical about using VB both in their sleeping bags and clothing... a bit quirky but there's sense in what they say.

http://www.warmlite.com/vb.htm

One key point is that you don't realise you are sweating when wearing modern wicking baselayers; and most sweating is a response to overheating. VB clothing puts you in touch with your sweat response and you'll be likely to remove excess insulation as soon as it isn't needed rather than filling it with humidity.

The counter argument for VBL in your sleeping bags is well put JB at HAE - these guys have a lot more experience of cold nights outside than I am ever likely to! As I am a heavy sleeper that doesn't usually wake during the night, I would gladly try VBL in a sleeping bag if the need arose, but can appreciate the inconveniences.

For UK users, I suspect that Scottish winters could easily merit the use of VB socks. And carrying a VBL is an alternative to the emergency bivvy bag so might be dual-function.

Of course, my illustration just goes to show that the wise option is to lower output to below levels that would trigger sweating when in extreme cold. However, the certainty of a hot shower and change of clothes is enough to bias me in favour of 'getting out in it' in any weather!

John

you're going to laugh at me, but SubZero make waterproofs (non breathable outer layer) with a 'pump liner' membrane and a means of draining the condensation from the bottom of the jacket. Not sure I like the idea that much (imagine my jacket getting gradually filled up with fluid!) , but maybe someone has tried it?

 http://www.subzero.co.uk/technical/shell.php

Ooops... didn't realise the other half had logged in!

John (who doesn't go by the name of Melodie) Burley

john, WILL YOU STOP IT!

i ordered yet more sz stuff earlier today!

the pockets at the bottom have a zip which allows access to the taiga pockets underneath only. the actual pockets in the fuera have no zip. things fall out of them and it's easy to think you have put something in the pocket when you've actually missed it. i find them a pain when not worn with taiga.

in fact, come to think of it. the taiga with the fuera jacket is probably the ideal softshell. putting the jacket on makes it "waterproof". it's all a bit on the warm side for activity though.

CP,

lol! I know - I suppose the advantage of VB clothing for Stephenson is that the end result is wearing a lot less... plus there's the fun of removing sweaty bodies from the inside. I love their photos... it always looks as though they just wandered into a campsite off the set of Zabriskie's Point...

Just about to buy a Fuera smock - can anyone tell me if it's water repellant when new or it specifically requires washing in TX Direct to make it water repellant?

Hi Alex. This is what the Paramo website says about the Fuera smock: "The Fuera Windproof Smock, made from Nikwax® Windproof, is lightweight, windproof, rapid drying and offers maintainable water-repellency when treated with Nikwax TX.Direct Wash-In."

It's not that water-repellent, and won't replace a proper waterproof, but is ok in mist, light drizzle etc.

But in answer to your question, I think you'd need to TX-Direct it to get the repellency in the first place.