condensation in zpacks hexamid

[Jeff McWilliams]

I was using my hexamid twin new with my wife in the Adirondacks the week of August 18. On Monday night we camped at Lake Colden on a damp, muddy designated site- the only one we could find that was not taken on a busy week. The dirt pad was a squeeze for the tent, and as such, the pitch was less than perfect.

during the night, temps dropped to around 38 and rained steadily most of the night. I lowered the beak on the hexamid for the night to prevent rain spatter.

we had a lot of condensation that night. I tried to minimize it by wiping down the interior several times. my wife slept in the back because she is shorter than me. she complained of spray when rain drops would knock condensation droplets off the inside of the tent. she also found it very difficult to sleep on her side without her shoulder brushing against the tent wall and dampening her bag.

any advice? I really want to make this work, especially since it was a sizable investment. I'd hate to go back to a double walled tent due to condensation issues, but dealing with wet bags is far from ideal.

[Andy F]

The only solution might have been a location higher, away from water, and more ventilated. But with rain and 38F temps, even that might not have prevented condensation. It's probably not a significant issue if you have a bag with good DWR. I've had condensation drip on my down bag all night in rain. I shook it off in the morning–no big deal.

I wonder if you or a custom gear maker could make a light 1.1 oz nylon liner for the Hexamid, similar to what Tarptent offers for the Rainbow and Moment?

[Randy Martin]

The issue isn't complicated. You couldn't have picked a worse campsite under the worst possible conditions for condensation. Lots of rain, temperatures at dewpoint or lower and camping right next to a lake. If you are going to use a single wall shelter you have to pick a better location OR have maximum ventilation and hopefully a little breeze.

For campsite selection near a lake you ideally need to be overlooking the lake and not right at it. Cold air settles and creates ideal condensation conditions right at the lake (any lake) so camp above the lake as much as is practical.

[M B]

Everything has tradeoffs
You have discovered single wall shelter limitations
You must decide if the low weight is worth extra effort to stay dry in circumstances

The Hexamid is no different from other shelters, better than some.
The twin is also not that big for 2 people.
Two hot moisture producing bodies inside, cold tent wall, poor ventillatiion
Nothing surprising at all about getting condensation.

Mesh screen is a significant barrier to air movement, much more than it would seem at first.

Other than ventillate well, and stay away from walls,and wet mesh with water running down it, not a whole lot other to say. It takes extra effort in cool rain conditions for sure.

[Jason McSpadden]

I agree with the posts above. Both tarps and tents require some learning and experience to set up and avoid condensation and other issues when it is raining and colder. The site selection and weather almost guaranteed condensation problems–its not the tarp's fault. You camped by a lake which is full of water and makes the air more humid than away from it. The lake probably sits lower than the surrounding topography–the air again is colder and more humid. You have rain–falling humidity! And the temperature drops causing the water vapor from your breath and body in the air to condense. Plus you batten down the hatches to avoid the rain from bouncing in–causing poor ventilation which in turn causes more condensation.

Again even with tents there is a "dance" that one has to do to avoid condensation issues except on the most windy, warm and dry nights.

What I do is almost always err on the side of too much ventilation. I would rather open the tarp up, extend it out as far as I can, lift the sides up at least six inches off the ground in rain to avoid the condensation. And then I find a happy spot in the middle.

I have a hexamid tarp solo without a beak. It is a minimal tarp but I think it is a good one.

You'll learn how to use this shelter. It just takes some time, experimenting and experience. But I think the process of learning is worth it. Think of it as an adventure!!!

[Tom Lyons]

Basically, regardless of anything else, if your tarp temperature falls below the dew point, you will get condensation on it.
Regardless of your breathing, or the wind, or closed-in, or whatever.
If that tarp temperature is below dew point, it will be wet from the moisture in the air condensing on it. That's all there is to it.

The key is to have the tarp no colder than the surrounding air, and be in the least humid location you can readily set up camp in.

Why does the tarp get colder than the air around it?
Because if you set up the tarp in the open, it "sees" the sky and universe as a giant heat-sink, and it actually gives up its heat and cools. You can see examples of this with solar cookers. If you place an item in a solar cooker in the night time and point it at the clear open sky, the solar cooker works in reverse as a cooler, and by morning the item in there is actually up to 10-20 degrees cooler than the surrounding air.
That's what is cooling your tarp off.
Park it under the trees, where the leaves are blocking the direct path to the sky, and it won't cool off as much, and might get less condensation on it.

Being in low locations near water is always going to be more humid than higher locations further from the water. When you have more water in the air, you get more amounts of water condensing on things than if it was less humid.
Use higher locations away from water if possible.

In the end, you are battling a natural phenomenon of water and temp behavior. You will not conquer it with a single wall shelter or tarp. But you can mitigate it to some degree.
It happens with a double-wall shelter too, but the water condenses inside the outer wall, and the inner wall is heated more by your bodies, so it's not as cold, and won't condense as much water on it.

[James Klein]

To better handle the spray, I would use a sleeping bag cover / bivy. Maybe you could just use a light nylon "sheet" (like out of .7oz/sqyd stuff). Course even with this your wife would still get sprayed in the face. Unfortunatly, if the two of you don't really fit without her hitting a side wall, the shelter probably isn't ideal — maybe with a bag cover you'd have been more comfortable with raising the shelter a little more?

A similar sized double wall wouldn't have prevented the condensation any better. Just would have been better at keeping the condensation away from you and your insulation.

[Jacob Blumenfeld]

You guys should have plenty of room in your hexamid twin for two people. Unless you are both really big people, or just used to the luxury of a larger tent. My girlfriend and I share the hexamid solo plus with no space issue and that's with all of our gear inside; even in heavy downpours, hailstorms, and thunderstorms we have never had room issues.

The condensation is not something that can be easily avoided, and I hear your pain with the rain spraying you guys with condensation. The good news is that the spray is not a lot of water, and most good bags have a dwr. We use 20 degree bags for weather down to 30 degrees, so even if the bags get wet it gives us a bit of wiggle room. I personally just ignore condensation spray, shake my bag off in the morning, then dry it in the sun during breaks/downtime.

Site selection, as others have said, is key.

[Jeff McWilliams]

thanks for all the terrific feedback.

lake golden sits at the bottom of a steep, 2000' deep "V " with Mt Colden on one side and Mt Algonquin on the other. I didn't have any other site choices except to hike another 3 miles which was not an option with my trail companions.

the site was actually about 30 feet above the lake edge. there was a little bit of tree cover above us – very tall birches as I recall.

our friend was in a one person big Agnes tent. I think a seedhouse SL1 literally 5 feet from us. minimal condensation on the outer fly, but no wet issues on her bag, so not really buying the argument that a double wall tent wouldn't be any better.

I'm 5'11" and 195 so not a huge guy. my wife is shorter but a little stockier, but she certainly could have been too close to the wall. I'll look into giving her bag a fresh DWR coat with Nikwax. She sleeps COLD and used a 15 degree down bag which is pretty puffy and also wore layers underneath. kind of like other active thread about cold sleepers on this forum.

I think I have a photo of the tent at that site I may post here this weeekend. I'm still on the road right now.

[James Klein]

Does your hexamid have a netting floor? Also, did you use a groundsheet? If not then that could have contributed to the difference btw yours and your friends by letting more ground moisture to the fly.

You friend may have just been cooler, thus sweating less. Also, I would be suprised if BA sl1 has 50% of the volume of heximid twin so you can't compare equally. I guess with a single wall vs a dbl…the inner allows the general air to stay warmer (allowing for more vapor to exist in the inner w/o condensing) and also blocks a portion of the water vapor (from you) from getting to the cold outer layer.

I have had pretty bad condensation inside a BA (sl2 i think) in the right conditions.

[James Klein]

Re: venitation….

I imagine there are conditions where increased ventilation makes condensation worse — especially with a tarp.

I imagine a large A-frame tarp set up under clear sky. If it was humid during the day (say from an earlier storm system or its near a large body of water.
In this case the ventilation helps remove your respiration/perspiration and at the same time it would also bring more saturated air to your cool tarp inner to condense.

Maybe this could help explain why your shelter faired worse than your friends (the sl1 is definatly better at keeping outside humid air off of the inside of its fly).

[Darren M.]

As an owner of a Hexamid Twin, and of similar size (6'0, 195lbs.). The twin is not as big as what others may think. If you are close to 6 foot you have to have the side near the door and the other side in not roomy at all.

I won't beat a dead-horse by rehashing the basics of condensation conditions and how to prevent. What I would say is that I've had success with my Twin when I've had company by utilizing what Joe now does with his Hexamid Long Tent/Tarp. Try to get the two side anchor points up somehow. I've used sticks (appox. 3 feet) and ran the guylines over them and back down to the ground. I've also used a nearby tree. Anything to get the height of those sides up and out of the way of your partner and their bag/quilt. This technique make a considerable difference in room in the twin for the second person, and also helps to minimize condensation.

Overall, a great tent but the unless your partner is small, the twin is not as roomy as other may think.

[Tom Lyons]

I have been using a similar arrangement in getting the side anchor points up higher with my regular tarp set-up. I use sticks in both back corners when I set up my tarp in a half-pyramid pitch, and it works nicely to give more room, and get better air movement from the rear side. I like it for both reasons.

Also, regarding the OP's comment about the double-wall shelter working, yes it works to shield the inhabitants from condensation, but the outer wall still gets it. It's just that the inner wall prevents it from falling on you, which I guess is the ultimate goal, but it's heavier.

Each person needs to define their own particular needs and goals for achieving it. Some people have individual preferences for certain creature comforts that are worth the extra carry weight, and some feel the lighter carry weight IS the creature comfort they are looking for.

[Jeff McWilliams]

Here is a picture of our site. (ugh, I hate our Pentax Optio waterproof camera).

Yes, it really was as damp and muddy as it looks, and I sure wish I could have found a better site. As I said, the tent to the right of ours didn't suffer the problems the Hexamid did.

To answer the question about a drop cloth. I sewed a tyvek drop cloth with 2.5" tub-like walls similar in design to the cuben drop cloth that Joe sells as an accessory to the hexamid.

As you can see, the raised wooden tent pad we are on forces all the guy lines to pull down, which probably made the ceiling height problem worse than normal. There's also a bit of sag in the roof line. I adjusted it after taking this shot, but noticed it had sagged somewhat by morning. I do not like the spectra guy lines. They're almost too thin and difficult to work with. I'll be replacing them with reflective guy line that is a bit thicker and easier on the hands.

That's my wife standing in the background.

[M B]

2 persons are going to make a lot more condensation than 1 person

The hex twin really isnt that big in adverse conditions where you must stay away from the wet netting. You also will have issues if you arent on flat ground, because you will constantly slide downhill into the netting. I have had that happen and when the cuben groundsheet touched the netting, water funnelled into the groundsheet.

Even with beak down, I have had to put sleeping pad and packs across entrance side to block spray, and water bottles and shoes between groundsheet and netting around perimeter. You do whatever you need to in bad conditions.

It is a minimalist shelter,not a 3 season tent. That is why it weighs 12oz. There are tradeoffs.

It takes extra effort to stay dry in poor conditions, especially when crowded with 2 persons. Never would I consider sharing it with someone other than a family member or such that I dont mind getting exceptionally cozy with in bad conditions.

I never had an significant condensation knocked on me though. It actually runs down the roof and walls pretty good, and wicks down netting. Even had a leak that never dripped, just ran down roof , the surface tension keeps water adhered to the cuben pretty good.

Are you sure it was condensation raining and not splashback from the ground coming thru the mesh?

[Jeff McWilliams]

M B –

Not really sure if it was splashback through the netting below or condensation from the roof above.

My wife's bag was definitely damp at both the head and feet the next morning, but not wetted through, so it didn't effect the down.

You're right, it's a minimalist shelter. If I were to carry a double walled tent to prepare for all possible conditions, like rainy nights in damp areas, then aren't I going against the UL mantra?

On my 2nd week in the adirondacks, we experienced another rainy night, but I was using the hexamid alone. My wife had gone home, and my make hiking buddy was in his own 1 person Marmot Eos 1P.

We were camped down in a ravine by a brook. I didn't have any condensation issues that night but I was getting some rain spatter coming through the mesh on the side where my head was. I had to adjust my tyvek sheet and move some gear, and then I was okay.

The hexamid definitely has its drawbacks. I'll experiment with using sticks to pull out the guy lines on the head and foot sidewalls and see if that helps.

I wish the hexamid twin were a bit wider so that two people found it easier to stay away from the tent walls and the spatter zones, and used a design similar to Joe's new Hexamid long, with small carbon poles to make the head and foot ends higher. Or maybe a way to make the back wall more vertical for the 2nd occupant.

[Ken Thompson]

"If I were to carry a double walled tent to prepare for all possible conditions, like rainy nights in damp areas, then aren't I going against the UL mantra?"

NO. If having a single shelter is the way you roll. The UL mantra suggests that you take the lightest option that will handle the conditions you experience. This could be a double wall bomber tent if you regularly get severe weather where you hike.
Get and use the right tools for the task at hand.

[Jacob Blumenfeld]

I have never had any issues from splashback with my hexamid. Maybe I am just lucky? The netting has always done a fine job of stopping a significant amount of spray.

In bad weather:

Make sure you pitch it with the backside to the wind.

Pitch it in a sheltered area if possible, even if it means hiking further or off trail.

Also, I always pitch the hexamid really close to the ground in bad weather. Like 2-0 inches off the ground. No rain spray getting through that.

Prop your groundsheet up around the edges with items that can get wet and that should help too.

Don't give up on the Zpacks hexamid, it's a great tent that IS 3-season storm worthy. Takes some getting used to as far as learning to sleep without touching the walls, and pitching it correctly for bad weather.

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