Waterproof Fabric and Breathability Ratings: Powder7 Guide

Powder7's clothing expert Lauren explains waterproofing and breathability.
You always see features like Gore-Tex, DWR, and 15k when you’re shopping for new outdoor clothes, but what do those features even mean?
First things first, technically, no fabric is 100% waterproof.
With enough pressure, eventually water will push through any fabric. So the key is finding something that is waterproof enough for your climate but also has other features, like breathability, that are appropriate for how active you plan to be next season.
A word on Gore-Tex:
In 1969 Bob Gore stretched polytetrafluorethylene , or PTFE, into a thin film and he discovered that the pores were 20,000 times smaller than water droplets but 700 times larger than molecules of water when in the vapor phase. This discovery meant that the film blocked liquid, like snow and rain, but still allowed water vapor, like sweat, to pass through. This breathability combined with extreme weather protection is what made Gore-Tex famous and ultimately changed the way people shop for outdoor apparel.
Gore-Tex is the actual membrane of the fabric, and since the 70’s many other companies have engineered their own versions of the membrane.
How about DWR?
In addition to the membrane, most brands will apply a DWR treatment to the outer layer of a waterproof fabric.
DWR stands for Durable water repellent and this treatment is what actually causes water to bead up and roll off the fabric.
The DWR treatment will wear off over time so if you start to notice that water no longer beads up on your garment, you can re-apply the coating with wash-in or spray-on DWR products.
Critically Taped vs Fully Taped Seams
Taped seams are another very important part of waterproofing
When traditional seams are sewn, needles puncture the fabric and create weak points where water is more likely to sneak through.
To eliminate those weak points, tape is melted over the seams to seal off the holes.
If it says critically taped seams, that means the exposed areas, like the shoulders, hood, neck and chest, have been taped but other seams have not.
Fully taped seams means that every seam has been taped to seal off any weak points.
This will be more weatherproof but is generally more expensive.
The Ratings
Here are some general guidelines for skiers:
-5k means the fabric is water resistant but not when the fabric is under pressure. With a 5k rating, you’d stay dry during light rain or snowfall.
-5-20k fabrics are considered waterproof because they will stop water from getting through unless there is significant pressure
a light backpack wouldn’t be too much pressure for these fabrics but if you wear a heavy backpack in the snow, you might start to see water penetrate the fabric over time.
-Anything over 20k will stay dry even under significant pressure, which is ideal in areas like the pacific northwest where heavy, wet rain is common.
-Gore-tex doesn’t use waterproof ratings like this, instead they just guarantee that you will stay dry.
Breathability
Often, you’ll see a waterproof rating followed by a breathability rating.
A 20k/20k fabric is water resistant up to 20,000mm of pressure and also allows 20,000 grams of water vapor to pass through a square meter of the fabric in a 24 hour period.
There are a lot of ways to test breathability, so it is not always standard between brands, but generally you can know that the higher the number, the more breathable the fabric is.
Breathable fabric is especially important if you are more active because when you’re hiking in the resort or touring in the backcountry, you will need the fabric to release the moisture and heat that builds up between your body and the fabric.

[@lemaylemay8452]

Great video , thanks !!

[@leonardobassi2794]

Brilliant!!

[@TheUnholyPosole]

What would you recommend for a WAP? ....Gore-Tex?

[@MP-zf7kg]

If you're exercising hard..... use a full-zip jacket and keep it about 1/2-zipped to start. For me, about 20 minutes in and the heat starts to build up. I have to mitigate that on really cold days so I don't get that terrible "soaked and cold" experience. Getting some cool airflow helps, and wearing wool underlayers helps.

[@isaacware4879]

nice

[@Ed-qn9kz]

Hello. Do you have any idea of what hydro shield exactly is? How to source it? It seems impossible to find the manufacturer on google. Hope you can help! Cheers

[@meowzic]

If i buy a tent that has a rating of 3000mm does that mean it only handles very light rain and snow? If so is there a way to increase that rating for heavy rain?

[@sonsofliberty3081]

I think dermazax has the edge over goretex, not that goretex is bad. But if you're falling in snow or like she said putting pressure on the garment. Backpacking, leaning on a tree, fell down, etc while hiking or hunting, you're going to freeze with a 20k raiting because water will make it's way in. Dermazax has a 31k and a 40k raiting that has a breathable raiting of 18k and 14k. So you do have a trade-off. 40x nothing is coming through the coat. In the back country you are going to build heat, if you want waterproof of 40k it's not going to let that much sweat or heat out, so get something with pit zips and several pockets that are mesh so you can unzip them to let out heat. In the winter it's actually dangerous because you're breathable insulation layer is going to wet out from the inside if you can't vent the heat you're building up. So pit zips on the insulation layer and outer shell should be used if you're doing a lot of moving.

[@riverthecat]

Really frustrated...even with expensive waterproof jacket, the perspiration on my body is cold and uncomfortable...can any thing be done to improve this situation..?

[@patbar8306]

Having a base layer that is designed to pull moisture away from the body can help. Usually something synthetic or merino wool is good. You will still be sweaty but it's supposed to help. You might want to find jackets that have vents on the side too.

[@adamcrompton4385]

I am quite hot and sweaty. I have left gore behind and I have paramo now Not quite as waterproof but breathability alot better

[@riverthecat]

@@adamcrompton4385 thanks

[@MP-zf7kg]

1-don't pull your jacket sleeves all the way down; let the base layers (or bare skin) be exposed to release some heat 2-yes about the base layers being wool or synthetic 3-wear a full zip outer layer, and begin your exercise with the zipper about 1/2-way down. Since I'm biking, I wear a shield there to block really cold air from directly impacting my sternum, but enough flows around to cool me down some.

[@ddfcoold]

does it mean that 20k breathable fabric is colder than 10k breathable or the warmness is independent from breathability?

[@powder7skis]

Great question! Warmness is independent from breathability because of a number of other factors like if there is insulation used or what type of backer is used with the membrane. If you want a warm jacket it might be best to look at jackets with insulation. Shells are meant to keep you dry and allow you to layer underneath for warmth. However some shell can have a backer that adds light insulation such as a wool or flannel backer. Feel free to call us at Powder7 if you have any other questions!

[@ddfcoold]

Tks!

[@meowzic]

Do they really construct a 65ft tube to test for waterproofing?

[@deanforway3318]

I suspect that they simulate the height using pressure. That way the test tube method means that the tube could be short