How water resistant is Windstopper

Hey-
I think the most apt comparative description of Windstopper is that it's a stretched-out, thinner version of GTX.

You might or might not be aware that the Dryloft used for years in sleeping bags is one and the same as Windstopper. I've had a Dryloft bag ~15 years now, still in great shape. In insulated items such as down bags and parkas, I haven't found any significant contamination problems–none, really. But those shouldn't dramatically affect the waterproofness, either–more so the breathability. I also have a Dryloft/Windstopper down parka, roughly 8-10 years old, still in great shape, no problems with the shell.

Keep in mind that Windstopper is intended primarily for exactly that–stopping wind. By virtue of its not being waterproof it is inherently more breathable, which makes it particularly useful in down items (there's a reason we no longer use GTX in sleeping bags). Stopping the wind prevents convective heat loss, obviously. In conditions where I'm using a Windstopper-shelled garment or bag, it's cold enough that it's not raining, so absolute waterproofness isn't as important–or as desirable. For when it's intended for use, I've found WS to be quite adequate. Hope this helps.

Hey Brad,

Thanks for your insight and experience.

But I guess what I'm wondering is: how water-resistant is it – will it stand up to light rain, hard rain for short periods? Or does it only leak at the seams (or when it's unprotected membrane is contaminated).

The only Windstopper items I have are insulated, so it's pretty hard to tell if there has been leakage, and if there has, if the water came through the seams or the fabric.

So, if Windstopper is extra-expanded pTFE, is the pore size sufficient to prevent real rain from penetrating, provided the membrane is not contaminated?

Have only owned couple Windstopper garments. A few sets of Yoko gloves for cold weather X/C ski racing/training and a Mt. Hardware (older made in USA) shell. They are both resistant to moisture from intermittent snow/sleet to a light rain. If a more breathable, wind chill barrier and very light moisture resistance is your need Windstopper works fine. Wouldn't be my 1st choice for keeping dry.

Windstopper is waterproof when new, I don't remember the pressure but it is more than enough. The issue is that it is not normally taped, so you get leakage on the seams, Also the coating may be different on the membrane than GTX so it might degrade after a short while due to contamination.