Goretex XCR Fabric

My experience is that all of these waterproof/breathable fabrics, including Goretex, are waterproof if properly seam-sealed and Goretex is particularly durable (no delamination as with urethane coatings). Under optimal conditions, all W/B fabrics breathe adequately. Optimal conditions means above freezing temperatures with a tarp for rain-protection, so that there is a temperature gradient between the inside and outside of the bivy to push any moisture out. My experience using bivies is with Outdoor Research models, made of Goretex, which I slept in for about 200 nights total during two hiking seasons several years ago. If you plan to use a bivy without a tarp, then you will get heavy condensation inside when it is raining heavily, because nothing breathes when it is covered with a film of water. If you plan to use a bivy without a tarp in the rain, or in sub-freezing temperatures (like in a snow cave), then you might want to consider using a Polarguard bag/quilt as well.

The big problem with using a waterproof-bivy is that it will be a sweatbox in summer. This has nothing to do with being a hot or cold sleeper. Almost everyone will feel uncomfortable trying to sleep in a waterproof bivy at 80°F or above. I no longer use waterproof bivies because of this problem. Rather, I use a bug-bivy with a tarp.

Cant comment on how much better it is than regular 3 ply..

Sounds like a good project but you will have to get a long piece 2+ yards to run seemless the whole length. I just ordered some from Rockywood in Colorado, there seem to be 2 different types, kinda the normal goretex xcr, then another type which is still XCR but has a micro brushed inner surface. its more expensive at around $35 /yd. ouch

If I anticipate rain, I usually use a mid and my sleeping bag, without bivy. Have had one too many sopping nights in my OR bivy

Hey Eric-

Thanks for the bit of info on the XCR types, and by the way, sweet last name…

I was curious about what you meant by a "mid". I'm just not that savy. Maybe short for pyramid? If i had to guess.

Anyways, thanks again,

Evan

when you hear someone say "mid" in the context of a shelter discussion they are usually referring to the black diamond megamid, a tepee style single wall shelter thats been popular with backcountry travelers in alaska for quite a while. It is floorless and supported by a single center pole (my apologies if you already knew what a megamid was and just needed the definition of the slang. I have been described as wordy on occasion.)