Could that Condensation in Your Bivy be a Leaking Floor?

Yes, a leaking floor is an obvious concern in a bivy without a ground cloth, or even with a ground cloth if spray is gathering.

Condensation can be a real issue under certain conditions. Your body produces a lot of moisture when you sleep, especially if you are nice and warm.
It's often hard to avoid some condensation if it is cool outside.

Also be aware that if you test for leakage by running cold water over a waterproof layer, you can end up with condensation on the other side and this can appear to be leakage.

Best to test with warm water.

I've had nothing but good experiences with my MLD eVent bivy. It's got a pretty durable cuben floor. Sometimes I use a 1/8" CCF pad under it as a ground sheet.

Steven you are right I've definitely experienced real condensation in my bivy before. However it leaked through so completely when I ran some lukewarm water over it that I'm sure its leaking. I weighed it and its now 5.5-6 oz. It was 6.5 oz to begin with. I'm guessing some of the silcone has worn off.

Edit – If you wake up in the morning and your sleeping bag is a bit damp how do you tell if its condensation or leaking? If the ground is moist, chances are there is moisture in the air too so it could be either one. I think the best strategy is to check your bivy floor once in a while to ensure its waterproof.

@Luke,

I agree, silnylon can wear through after use on rough surfaces.
I have no doubt leakage can be an issue with a silnylon bottom. That's why I use a ground cloth or sleeping pad under mine.

You can put a layer of mineral spirits:silicone 10:1 or whatever.

That will make it waterproof in my experience.

I would advise you to steer clear of the Ti-Goat bivy.  mine has some issues with the quality of its build.  A zipper across the top is a pain when compared to a side zipper.  Finally it seems to be made very small.  I feel that the loft on my quilt is compressed in it.

I want to get another bivy to use with my son.  I had pretty much settled one from MLD (so much positive feedback on their products), when some items from Zpacks arrived.  I'm very impressed with the quality, and I'm seriously considering his bivy.

Jerry
Thanks for the tip. I did re-coat a tarp that was misting through, so far so good. I kinda wonder how long such a treatment would last on a bivy. I imagine coating the INSIDE would be a good strategy.

Paul
Thanks for the heads up.

I coated inside and outside

After maybe 10 nights, the outside started peeling off, so I just rubbed it off with my hands with a little effort, just to minimize the mess. Next time I won't coat the outside.

After maybe 50 or 100 nights the inside seemed to still be working. That worked pretty good.

Of course, it depends on the silicone and the amount of mineral spirits.

and then I made a new bivy with Shield silnylon from thru-hiker.org and it didn't leak – better solution