Why does Gore-Tex fail to be both breathable and waterproof simultaneously?

Question

What is the reason why Gore-Tex jackets cannot possess both breathability and waterproof capabilities at the same time?

Answer 1

Gore-Tex is both waterproof and breathable, but because of its structure, it is restricted to performing either of the functions at a single time. The breathability rather of the fabric baffles relies on the fact that the outer layer does not get wet. If the outer layer is DWR-treated and becomes sodden, moisture vapor gets trapped and condensation forms inside the jacket, resulting in the wearer being wet from the interior. DWR is not very efficient and hence, needs to be replaced; this wear condition is popularly known as 'wet-out'. The situation is made worse in high humidity environments where the jacket is unable to draw in fresh air.

Comments

To be honest, I worked at an hiking/trekking shop and I knew this for years. Since then I became a huge fan of ponchos. Especially expeds‘ pack poncho. Ponchos allow more airflow underneath and do not even try to lie about “breathability” and protect you AND your gear from becoming wet. Also it is easy to put it on/off during light rain or when the rain pauses for a few minutes: The poncho can be attached to the Backpack so you just throw it over your head and it hangs there behind you and when rain sets in again you just reach back, grab the thing and pull it over your head again. And in case of very heavy rain or wind you can combine a poncho with a pair of rainchaps to protect your legs, but they leave your crotch open which helps ventilation by a higher amount!
That said:
Great content! Thank you for that much time and effort! It’s always a pleasure to read your content!

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After spending $1000 on a “gore-Tex pro” jacket, I thought it was the best jacket going for years. But after multiple rainy days on trail I noticed I was soaked on the inside. It was a hard pill to swallow realizing that the jacket was just as useful as a $30 frog toggs. Confirmation bias is totally real and it hits close to home

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100%. I've worked professionally in the ski industry as a Lift Operator for years, and we have to spend hours standing in blizzard conditions, rainy conditions, and everything in-between while working hard shoveling snow and doing other physically demanding work. And I can tell you as someone who professionally is paid to be outdoors and do sweaty work: the best waterproof jackets you can get, are just the fully rubberized heavy duty rain gear. And if you want to stay warm, just have a puffer underneath. These crazy goretex systems are just completely unnecessary and most of them get you wet anyway. Just wear an oversized rubberized rain jacket so it allows air to move underneath it and you'll stay much dryer.

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I work as a full-time glacier and alpine guide in Iceland and have owned many Goretex layers. I have noticed that a nice new Goretex jacket works well during a chilly alpine ascent (due to both the humidity difference and fresh DWR coating). This is why I only use Goretex for high-alpine trips or ice-cap related activities. When it comes to daily glacier guiding in the rain (a high-humidity environment), Goretex is worthless. What I started doing is just buying cheap rubber jackets/pants that both last longer and are exponentially cheaper. Great content!!

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Thanks Dr Science!  You have scientifically proven what my own experience has been telling me for years.  Every time I have been caught in substantial rain it became clear, relatively quickly, that my jacket was no longer adequately breathing and I was getting wet from my own perspiration.  Now I know why, and that I no longer have to chase the illusion of a “better” rain jacket.  Very helpful - thanks!

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I have personally experienced this with numerous gortex products. It doesn’t mean they are useless, they just are not useful as advertised. I do get good results from my boots that have goretex. I think the difference is my feet pump air as I walk and the fabric is a lot thicker allowing more air movement between the wet outer layer and the humid inner area.

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Really appreciate this kind of content! Really good companion to the content that did something similar for motorcycle jackets. As a runner I realized what you concluded in this content and opted for a much cheaper $180 jacket that doesnt use Gore-Tex but has goodish breathability and okay water protection. I just couldn't justify spending multiple hundreds of dollars on a jacket that with exposed membrane (like the Gore R7 Shakedry) that I would almost certainly need to replace in a few years of heavy use because it literally would just not last that long. The exposed membrane literally wears down with things like a running pack on for example.

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It's one hell of a trick to pull to convince people that you can be (completely) dry outdoors when it's raining. I mean, you can for a while, but not long term. Like in the content - water is falling from the sky. You can cover against it with an umbrella, with GTX, with a rubber suit, whatever but eventually you will get damp, either from the moisture in the air or from your own body.

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If you look through the different membranes they make you'll find that they already have this fabric dialled, it's called gore shakedry and has been implemented in mainly road biking and trail running attire. Due to it essentially being a reversed 2L membrane it shed water off immediately and had a waxy finish, it worked exceptionally well in rainy conditions but due to the fragility of the outer fabric it meant that the membrane would break down under heavy loads. It was designed for little to no need for packs (road cycling, running and trail running) and I can say that with a heavy pack my jacket lasted under a year before there were major leaks in the shoulder and hip areas of the jacket, this too applies to any waterproof and breathable jackets with super light membrane qualities as they're mainly designed to be used sparingly and infrequently in hot climates or in extremely high output pursuits where large packs are not involved

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Edit; firstly I’m a fan of the channel. Secondly, GoreTex can be both breathable and waterproof simultaneously, assuming ‘correct’ conditions for the fabric to work efficiently. Gortex works, but it has its limitations. Your test created a humidity equilibrium either side of the fabric; of course this leads to no further evaporation. As you say, in cold/low relative/absolute humidity environments goretex will perform just fine. Raining isn’t a guarantee of high humidity as liquid water and water vapour are two different things, and the DWR is there to mitigate surface liquid from wetting out the fabric. If rain persists, humidity will rise due to the liquid rain beginning to evaporate; raising absolute and relative humidity. However rain is not an indication of inherent high humidity to the point that makes GoreTex immediately ineffective. In cold mountain environments with high winds, driving snow and low absolute humidity with the user exerting a moderate effort (likely the largest use case scenario for GoreTex) it’ll work just fine.

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Thank you for an excellent content. Quite a bit of research involved. Hhhhhhhmmmmmm.....from an engineering standpoint there are two requirements for these micro-membranes to work: water has to be in a vapor state; and it has to be under pressure. That is why the fabric works so well in the steam demonstration but doesn't perform with garments. With the steam setup, water is both fully vapor and is at a high enough pressure to force it's way through the fabric. In clothing, first water is present as liquid sweat as it come out of the skin (mostly liquid water + minor salts + oils, more likely to plug the micro-pores), and then there is not nearly enough pressure inside (almost zero) to force the small amount of vapor out anyway. The only 'breathable' fabrics are things like fishnets with enough open space to actually allow moisture to pass through without having to be under pressure. My preferences are ponchos for rain gear and Wiggy's sleeping bags (silicone treated polyester fibers with a high loft, good moisture control). Still open to experiment.

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The problem is people thinking they need a gore Tex jacket for hiking. Its purpose is for high altitude mountaineering where air is way dryer and the jacket works best in those conditions. It will never be wet and breathable at the same time, but it does allow some breathability over cheap rain jackets.

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Thank you!! Been burdened by wondering why the heck I end up soaking wet in the rain to matter what.

I will say that there is still a big use case for breathable and waterproof at different times, namely in shoes and boots. Thanks for the incredible effort!

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Thank you, this explains why I get wet while wearing a Goretex raincoat when it is raining.  Not what you want when it's raining, you definitely want to stay dry.

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I found out in the 90’s when I was a long distance runner that Gortex didn't breathe very well. Since then I've used Gortex drysuits when I've been whitewater kayaking and even when I've come out of my boat & fully in the water they've kept me dry but if the weather is warm then sweat can definitely build up.

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I think it even worse that stated: If you have Gortex boots even on a low humidity warm day, the rate you create moisture overwhelms the silly slow rate the gortex can breath. You might as well be wearing plastic bags on your feet if you want to ford a stream. It is completely worthless.

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Gave up on goretex boots years ago.   Oh and pit zips are the bomb!

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Wool for warmth, oilskin to keep you dry. There's a reason that's what farmers wear.

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Well, it's breathable for the days it doesn't rain, and it protect from water the days it rains, it's not that bad.