Tents vs tarps/hammocks or yet another condensation thread

[BillyBob58]

Nope, I'm not at long last getting soaked by condensation in my HH non-breathable Super Shelter or or space blanket in my Pea Pod or VB clothing anything else I sometimes use. Though I guess I would deserve it with all that non-breathable stuff!

I really felt like just posting this over in this thread: http://www.hammockforums.net/forum/s...ad.php?t=62400

but then thought it might be hijacking, because this concerns tents as much as hammocks, so thought I'd better just do a new thread. So forgive me Yessiree if this dilutes your thread, and mods if needed can just put all this right back into your thread and close this one, fine with me!

So let's see: Yessiree's TQ was really covered with condensation. Apparently about the entire TQ and not just the head area. Shug pointed out his very helpful frost bib solution. To which Yessiree replied:

Wow thanks! seems like it is easy to over look something so simple! what really gets me is I have been a ground dweller in -30f in a 4 season tent and not had this problem? Again thanks Cause being wet an cold really sucks! been there! hey Shug enjoy your vids!

To which I replied:

Very interesting point! Is this problem worse in hammocks for some reason? Is the double layer tent's added insulation allowing us to get by with less condensation, even sometimes with more than one person in a tent?

Then again, it's not like I have not heard of condensation problems in a tent. There was that famous antarctic ( or arctic? ) expedition where their huge synthetic bags ended up weighing a ton due to frozen condensation within the insulation, and I'm pretty sure those guys were in tents. Plus lot's of other less dramatic examples I can think of.

And then a light bulb turned on in the ever decreasing memory section of my brain, and wanting to discuss this is the main thing making me think it might need a new thread.

The year of the first huge Yellowstone fires ( 87? 88? ), 1st week of September, a buddy and I went on my first trip back to WY's Wind Rivers since my NOLS course there a few years previous. I was taking a minus 5 rated Marmot bag with a Gore-Tex shell. He had a 20 or 25 rated semi-rectangular bag with a regular shell, might not even have been DWR. I was a little concerned that might be a little marginal, though we would be inside a 4 season TNF West Wind 2 man tent, which had proven quite bomb proof. ( though small- I'd hate to be trapped there for long with another stinking guy) I offered him my GTX bivy for a little extra warmth and water protection, but he refused it saying he did not think he would need it and did not want to carry it.

So, flew to SLC Utah, got the rental car, drove 4 or 5 hours to the WY trail head at 9100 ft, and started hiking in at night. Camped 1st night under the stars at Big Sandy lake, looking at the silhouettes of jagged peaks in the night sky. Spent the next night a little higher at Black Joe Lake, then next day hiked over Jack *** pass to camp at the Cirque of the Towers and Lonesome Lake. We were going to spend a couple of nights there and go back the way we came, but my buddy gets the idea to go out by a different route. So we look at the maps, and make my 1st ever trip over wild and wooly Texas Pass, planing to do a big loop back to the car.

Now let me say that for the trip so far, there had not been a low below 40, no wind and no rain. Truly his decision to leave the bivy behind was pure genius, plus I was probably carrying too much bag. But after we get down from Texas Pass and start heading west on a trail, we see a storm heading our way with lightning striking the trail! We camp by a lake and it drizzle rains all night and all the next day, maybe the occasional hard rain. But now things go awry for my buddy. We had the tent pitched perfectly, and I was not even aware of it raining all that hard, but my bud wakes up to a bag soaked in the foot area. We never could figure out how water got in that 4 season tent. At the foot end was a small vent, but it was very close to the ground and very well covered by the tent's fly. You would think even side ways rain would have trouble getting past a fly covered vent only a few inches off the ground. But water came from some where, and my bag was fine and the last foot or so of his bag was quite wet. And, we had to pack up in the rain and get going. It kept drizzling or raining on us all day.

That night, to escape the stink and snoring, I slept out under an overhanging rock, as the rain continued. We set the tent up for my buddy. The front went through, and it dropped to 15F. He froze his butt off for a long miserable night, plus his boots froze solid. Poor guy had a miserable night, but you pays your money and you take your chances. The good news was we were hiking out to the car that day, so it could have been a lot worse, as there was no sunshine for drying down.

I'll give the reason for this rambling in the next post.

[BillyBob58]

OK, all these years I have puzzled over how his bag got so wet when we were supposed to be so well protected. I tested that fly both before and after with a hose, and it proved completely water proof. To repeat, the vent could be closed of if desired, but even with the top few inches open, that only gave you a few inches open about 6" above the ground and well covered by an over hanging fly. It would really be hard for side ways rain ( if we even had any ) to blow under that fly and then would have to travel upwards to get in the vent. Kind of like if you had a tarp's edges pitched lower than your hammocks bottom when occupied, and rain not only blew in from the side under the tarps edges,but then managed to turn upwards over the edge of your hammock and land on your face. Same principle more or less.

But in recent years, I have read by the guys over at BPL about the tendency of the foot loft of their down bags collapsing - from condensation - way before any problems arose with the rest of their bags. And one time I got soaked with condensation camping in very humid, foggy conditions at about 45-50F, but it was all in the foot of my HHSS pad and my PG bag ( but did not cause me any warmth problems, and both dried very quickly! ) I have started wondering if a lot of folks cold feet are due to super high humidity in the foot area of their quilt plus some condensation. Other folks here at HF report condensation problems in the foot area with CCF pads, unless they put the pads inside the foot box.

So, could it be after all that pondering about how in the heck rain got into that well sealed 4 season tent and soaked the foot of my buds bag, that it turns out rain did not get inside? And the villain was instead condensation in the foot area of his bag? It seems to me maybe so. There was no obvious wetness anywhere other than the foot of his bag, or actually the foot area inside the tent.

The problem is that I did not have a problem. Even with that GTX shell, condensation originating inside the foot box should have given me the same problem. Maybe even worse with my shell which was less breathable than his. But my bag did show some overall loft loss after 5 nights when I looked at it after I got home, maybe 1/4 of the loft was lost. But, maybe I did not have a problem just because there was so much more reserve in my bag, minus 5 vs + 20 or 25?

What do you guys think? Was this a case of condensation in the foot area collapsing loft, rather than what we thought for 25 years? And could it be that a simple pair of VB socks could have saved this guy a lot of misery?

If it was condensation, this gets back to the question: is there less condensation in a double wall tent that under a tarp in our hammocks, or are they the same? This question arises from Yessiree's experience of having NO condensation in a tent even at minus 30F.

So also what do you guys say about that: less condensation in a tent, or the same or even more?

[FLRider]

Been pondering double-wall designs versus an hammock for a bit now...

Note: I have very little experience with true cold-weather camping (my current record for being out in the woods is 21* F, and that was in my hammock last year; my coldest tent experience was 30* in a double-wall on the beach and we [Mrs. FLRider and I] had very little condensation trouble, but that was with two layers of cheapo synthetic bags spread like comforters). With that caveat, it seems like foot moisture is likely part of the problem that occurred, yes.

Let's take a look at your bags, first.

He had a non-waterproof bag that was rated for a much higher temperature than yours. Regardless of marketing hype, GoreTex does not transfer water vapor at a particularly high rate. Which means that the outside of your bag wouldn't have shown the soaking on the outside that his did. Now, the inside should have--but it might have averaged out over the entirety of the bag, due to the fact that the GTX wouldn't transfer water vapor as quickly as a nylon shell would. You mentioned quite a bit of loft loss (I consider 25% of loss to be huge, but that may be my personal inexperience with down bags and cold-weather camping talking); I figure, based on your story, that you did have condensation issues. They just weren't bad enough, compared to the bag rating and the temperatures you were sleeping in, to make for an uncomfortable trip.

Second, let's look at tents versus hammocks.

Hammocks have the advantage of avoiding condensation under relatively dry conditions where there is mild airflow versus a tent. Same as a tarp set-up. In humid conditions, they don't have any advantage over a single-wall tent whatsoever--the moisture is going to get in regardless.

However, versus a properly-vented (to allow as much of your personally-emitted moisture to escape) double-wall tent, they are not quite as good. The reason for that being that your body generates enough heat to raise the temperature of the inner wall (and everything inside of it, including your insulation) on the tent to above the dew point--at least it does in theory. The outer wall will likely be at or below the dew point, but that doesn't matter to you since frost or dew on that side of the tent doesn't affect your sleeping insulation (in theory).

Now, this can probably be achieved with an hammock with a sock or overcover/undercover design with a closed winter-style tarp. The tarp will likely wind up with condensation on it of some sort, while the sock will remain warm enough to avoid that and keep the inside warm enough to avoid condensation on your sleeping insulation. The trick is venting it enough that your personally-produced moisture has a way to escape to the colder area outside of the sock.

At least, that's the theory. I intend on giving it a try as soon as I can afford to make a winter tarp (hopefully some time this month or next, but holiday shopping may/probably will take precedence over personal desires). I've already got enough material to make an overcover/undercover system...but I still need to make my internal insulation for temps below 40* F. We'll see...

[BillyBob58]

Thank you for your thoughts and input, FLR. I absolutely agree - and have always figured - that I had condensation due to the less than cotton t shirt like breathability of that GTX bag. Just based on that loss of loft.

I was not all that alarmed at that amount of loss, though if I had been pushing it's minus 5 rating I would have been more concerned. It was a 7.5 or 8" total loft bag, and when I laid it out once I got back home, I could see it was maybe 6" of loft if memory serves, so maybe 20 to 25% loss. I still thought that was not horrible considering 5 nights, no VBs of any kind ( not even VB socks which I have used on occasion since 83), and two nights sleeping under the stars, and one of those a 15F night. I slept warm enough BTW. I agree with you that I probably just has enough reserve to get me by.

But while not being surprised that I got some built up condensation, I never considered my friend got any with his very breathable bag. We both just thought, and with a feeling of being let down, that rain had blown into the tent through that vent. It sure was a blessing that this happened at the end of the trip and not the 1st night.

And also, I have observed such loss of loft with down gear. And usually on week long trips about the last day or two. In fact, I've seen it happen with the same guy in my example above, on another 2 occasions. One trip in the same WY mountains, another in Olympic National Park. On the WY trip, he had a summer rated Pea Pod with a separate TQ. On the other, he just had a TQ and whatever bottom insulation, can't remember what. Maybe he is just a vapor machine?

Anyway, I am still pondering Yessiree's of no condensation problems at minus 30F on the ground in a tent, but lately in a hammock he has had significant problems. But if my buddy's bag got so wet due to condensation in a double wall tent, then there might be an advantage but apparently still does not solve the problem.

Other opinions? On
1:if that was condensation that soaked my bud's bag in the foot area and not rain.
2: is a double wall tent likely to have significantly less condensation than a tarp with all of it's inherent ventilation?

[nothermark]

I have been thinking condensation since about half way through your original article. I think the tent problem was the cool air coming in the vent that hit the warm, moist air from both of you breathing. It condensed out of the air and collected on both bags but soaked his because it was not waterproof. It may also have been that he got more cold air on his side. (Don't know). If it had not been for the vent the condensation would probably have ended up on the underside of the fly. Either way you both would be picking up condensation in your bags on a steady basis. That seems to be a constant in winter camping from what I know.

My impression with camping in below freezing conditions is that one may need to actively dry ones sleeping bag if out for prolonged periods. A known amount of water is put out in perspiration and respiration. Vapor barrier clothing will help contain the moisture from perspiration. There is no way I am aware of to contain respiration but things like the frost bib will collect it. Anything collected has to be dealt with on more than a long weekend trip. This should become an interesting thread. ;-)

[Peter_pan]

BB58, etal,

There is a tendancy for tent sleepers to lie head up on slight slants...On average they then slide to the foot end... The footend is often in contact with the sloping tent wall.... Condensation on the tent, caused by the thremal plane of the heated interior hitting the defining plane of thin nylon with the cold air above, seeks the low point if it builds up enough...Here it contacts the foot end.... Often as well there is a puddle there caused by the bathtub floored tent designs....Enter the other more common problem where the bag footend is off the pad and soaking up the water as if forms in the low spot... (worth notting that this will effect the slleper on one side more than the other because the site is almost always less than level to the side as well as the length)... Sometimes the efficiency of the bag soaking up will eliminate the evidence of the "puddle factor".

It is also possible, in your case, that the use of the bivi inside the tent waterproofed the bag from this wetting issue.

Also note... There are many articles and photos of those in such tents or longer periods wiping the interior walls ith pack towels and bandanas and wringing them outside the door to fight the overall condensation issues.

Point...Condensation is an overall problem... Not a "hot foot " issue... In fact, the exhaled, moisture laden breath is the greates source of condensation, especially when ambient humidity is high and temp conditions create the dew point defined by the nylon.

My $0.02.

Pan

[fallkniven]

Sometimes if the ground is wet enough, water can soak through the floor, or get trapped between the footprint and tent, easily letting it to soak through.
I've spent a lot of time in a tent in the cold. As Pan was saying, condensation always builds up on the tent walls, it rolls down, and sometimes I'd hit the wall with the foot of my bag, and get it all wet.
Also, condesation always liked to build up inbetween the tent floor and my pad I was laying on. When car camping I'd put a towel in between.

[BillyBob58]

Good food for thought one and all. Had not considered the off level and probably higher head end possibly being a contributor. Most definitely as a tenter I always tried to make sure my head was at least a smidgin higher than the foot end.