Best stand-alone bivy?

I see your point, but with all the sticks and stakes, I would go for a 1/2 pryamid or one of the poled solo tents. The difference in footprint isn't that much different. I think the step up from a bivy in really tough stuff is something like a tunnel type. You might need to stay longer and need a dry place for managing gear.

My expectation of a bivy is for a trip of a few days in prime season to make sure you can deal with any changes in the weather— cowboy camping with an insurance policy.

"My expectation of a bivy is for a trip of a few days in prime season to make sure you can deal with any changes in the weather— cowboy camping with an insurance policy."

Lots of choices there, MLD, etc, that are much, much lighter and will do the job.

Miles Gear seems to be what you are looking for. His bivies come completely seam sealed and he does custom work (including different floor materials) – just ask. The upper material he uses is waterproof and quite breathable, although a little bulky.

I shared a double trouble with my dog for several nights and had no condensation. I never used it in the rain. The bivy added almost 15 degrees of warmth.

I decided I'm going to cut my 6 oz waterproof bivy in half.
I just bought some kite grade tyvek which weighs less than regular tyvek on amazon.
I'm going to create a reversable bivy with half tyvek and half
montbell dri tec waterproof material.

When it's raining a deluge, I will use the bivy under my 5oz tarp with the
eventmontbell dri tec side on the bottom so if a river changes course under me I'm still dry. The tyvek top can handle spray and condensation just fine and it breath equally well as the eventmontbell dri tec side.

When it's dry out and here it's sounds counter intuitive but when the ground is dry then I will use the tyvek side as the bottom which is 90 % of the time. The event on top breathes well, the tyvek handles rocks and pointy sticks better than any other material.

I'll save weight by never bring a ground cloth again and I'll have great protection if it does rain and the tyvek doesn't slip around and I'll never have to worry because it will be wide enough that my neoair will fit inside the bivy and on most nights I'll just cowboy camp and not set up the tarp at all.

Dale,

What conclusion did you arrive at? If you truly want to lay out in the rain in a bivy then the eVent top and whatever waterproof bottom you like would seem like the right combination.

I have a full Pertex (don't recall the actual fabric spec at the moment) bivy that I've got some use on but I fail to be rained on in it. Hopefully I can rectify that this winter. Anyway, it's heavy for a bivy but probably in the ballpark of what you're asking about. Something like this or an eVent bivy. You should still expect condensation inside, especially when the humidity is high, such as in a rain storm.

I'd concur with others like Tony who suggested pairing a lighter breathable bivy with a tarp though. That setup provides 3 ways to camp… bivy only, tarp only, or bivy+tarp and will be a lot more comfortable to ride out the storm in than a bivy only – but I'm guessing you know all of this and might have thought it would just be easier to use the a shelter with full protection in liu of tarp+bivy (which arguably could be easier, more comfortable, and possibly lighter).

Bivvies are sort of a conundrum. Personally I've found they work best in situations where I don't really need them to begin with; that's sort of a bitter irony. I do like them for bug protection, to pair with a floorless shelter in the snow, and in situations where I'd like a little extra protection, say from rain splatter or nighttime dew. My latest foray into bivy trials has been an M90 and Cuben (bottom) bivy from Borah Gear. The M90 seems like a pretty nice material for durability and minimal protection (no comment on longevity yet). I realize this is not what you asked about but just thought I'd leave it as a parting thought.

I have a used Titanium Goat Ptarmigan bivy on the way that is not a stand alone design either, but very light and my plan is to use it with a poncho. I think that style is acceptable for summer cowboy camping, supplemented with the poncho for unexpected rain.

The search continues. The Black Diamond Twilight bivy has been the most appealing production type bivy, mostly because of the weight and fabric. The hooped bivies from Outdoor Research look like good designs, but weight and expense push them back from my front line choices.

Bottom line? No free lunch. Unless the design is dead simple and light, I might as well use my Gatewood Cape. If I have to fiddle with poles, stakes or lines, a bivy isn't worth the drawbacks of exposed rain entry, condensation and restricted space.

If money was no object, and if i actually needed it (i don't really), would love to try out an all WPB cuben/eVent bivy with hoop. I would still use polycryo beneath it though, because even if i was that wealthy, it would still offend my Scottish heritage sensibilities and frugal-practical side.

As an aside and not really related, i happen to think combining the ultra lightweight cuben with polycryo would be an absolutely fantabulous combination for shelter material. Cuben for the tensile strength to take the load, and polycryo outer to help protect the cuben and provide long term waterproofness, plus double wall design to reduce condensation.

There was a time when I often used a poncho/tarp with bivy. The bivy was needed to overcome the small surface area of the tarp.

New materials allow much bigger tarps (i.e. 8' X 10') at very light weights. With a large tarp, no bivy needed. But the tarp cannot be used as rain gear.

Every thing is a give and take.

I used to use bivys on almost every trip, but haven't used one in 3 or 4 years. With my Hexamid or large Cuben tarp @ 5 ounces, my bivys are now obsolete.