Single or double wall depending on sleeping bag material?

[Earl Grey]

After thinking and analyzing alot of things, would it be logical to decide what fill of sleeping bag you are going to get THEN decide what type of tent? For instance if you get a pure down bag, then a single wall wouldnt make much sense since they do not ventilate as well as a double wall with the fly off. On the other hand a single wall could possibly keep out moisture better than a double wall which would keep a down bag dry(er). You could say just get a synthetic bag and not have to worry about such things but they do not compress as well.

[Tipi Walter]

There are so many variables regarding this subject that it usually boils down to personal preference. In cold winter camping tent condensation and therefore bag surface condensation can be a problem whether you're in a single or double walled tent, hence the use of Dryloft in good winter down bags. I have committed to the use of a down bag in all seasons and so I let that decision dictate what other gear I'll get and use(I.E. a double walled tent).

[Frolicking Dinosaurs]

The best ventilation of all comes from using a tarp and ground cloth.

IMO, the second best ventilation comes from hybrid tarp-tents -- models like Henry Shires tarptents which are basically a floor, bug net walls and a shaped tarp in one package. Several other manufactures of ultralight equipment make similar tents.

The other way to assure ventilation is to tarp over your tent and leave the fly off or partly off and / or leave door and windows open (with bug net zipped.) We use a large sil-nylon tarp over a tiny bivy tent. It gives use a huge area of dry space, protection from the worst blowing rain while allowing us to keep the entire bug net roof exposed and the front door wide open if we wish. Not a bad set up for two at 4 lbs, 3 ozs.

[Kerosene]

Just get a down bag with a durable water repellent (DWR) coating and you will have addressed your condensation issues, regardless of shelter. Such a bag can be useful even in a tarp or shelter when a cloud rolls in and gets everything damp.

[Earl Grey]

Just get a down bag with a durable water repellent (DWR) coating and you will have addressed your condensation issues, regardless of shelter. Such a bag can be useful even in a tarp or shelter when a cloud rolls in and gets everything damp.

Is there a commercial name for this? Im looking at some of the kelty bags. Would it be possible to use some kind of aftermarket sealer to accomplish the same thing if its not on a particular bag?

[orangebug]

Look at the details of any of the good down bags - Feathered Friends, Western Mountaineering, etc. Expect to pay a premium for quality, and for the bag to last a lifetime.

[Footslogger]

Is there a commercial name for this? Im looking at some of the kelty bags. Would it be possible to use some kind of aftermarket sealer to accomplish the same thing if its not on a particular bag?

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One material used to achieve this effect is called "Dryloft" (I believe it is a Gore product). The aftermarket treatments are generally "Durable Water Repellant" coatings and typically applied via aerosol or pump spray. Two such products are Techron and Revivex.

I have a 10 degree down bag that has the Dryloft cover and it has been exposed to severe condensation and freezing rain without ever suffering leakage. I also have a 20 down bag (REI SubKilo) that I have treated with the Techron.

This past weekend I carried the SubKilo up on the CDT here in Wyoming. The temps dropped into the high 30's at night and we had a major thunderstorm with blowing rain. My single wall tent suffered some condensation and during the night I noticed that the foot end of my bag was coated in moisture from rubbing up against the inner wall. The Techron appeared to work well, as I did not get cold feet and in the morning the down filling was still dry and well lofted throughout the bag.

Hope that helps ...

'Slogger

[Earl Grey]

Look at the details of any of the good down bags - Feathered Friends, Western Mountaineering, etc. Expect to pay a premium for quality, and for the bag to last a lifetime.

Id love to get something like this but thats just not in my budget as im still in school. For the price of one of those I could get a tent, pack and bag. Maybe in the future when i get out in the "real world" ill be able to afford something like this.

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One material used to achieve this effect is called "Dryloft" (I believe it is a Gore product). The aftermarket treatments are generally "Durable Water Repellant" coatings and typically applied via aerosol or pump spray. Two such products are Techron and Revivex.

I have a 10 degree down bag that has the Dryloft cover and it has been exposed to severe condensation and freezing rain without ever suffering leakage. I also have a 20 down bag (REI SubKilo) that I have treated with the Techron.

This past weekend I carried the SubKilo up on the CDT here in Wyoming. The temps dropped into the high 30's at night and we had a major thunderstorm with blowing rain. My single wall tent suffered some condensation and during the night I noticed that the foot end of my bag was coated in moisture from rubbing up against the inner wall. The Techron appeared to work well, as I did not get cold feet and in the morning the down filling was still dry and well lofted throughout the bag.

Hope that helps ...

'Slogger

Would applying this on a non Dryloft bag give it Dryloft properties? I am wondering if you use this chemical on a bag that isnt Dryloft what would happen to the material that the shell is composed of. The Kelty bag uses PR349T which is a polyester type of material.

[Footslogger]

Would applying this on a non Dryloft bag give it Dryloft properties? I am wondering if you use this chemical on a bag that isnt Dryloft what would happen to the material that the shell is composed of. The Kelty bag uses PR349T which is a polyester type of material.

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I would have to say NO ...that applying a DWR treatment to a non Dryloft covered bag would NOT give that bag the same properties.

Dryloft is a GORE product (an actual laminate/membrane) that renders the sleeping bag waterproof. For what it's worth it also reduces the breathability of the bag and makes it a lot harder to compress and get into a stuff sack for backpacking.

The DWR treament is essentially a polymer that coats the outer surface of a garment/sleeping bag and causes water molecules to bead up and roll off rather than seeping through the "weave" of a synthetic fabric or being absorbed by (in the case of a hydrophyllic) and soaking it out.

Plus ...a DWR treatment is subject to abrasion and has to be reapplied at regular intervals to maintain it's properties.

'Slogger

[dloome]

I don't have any specific reccomendations for tents, but I'd still go with a well ventilated single wall tarptent/tarp in any weather. A Pertex, Epic, or similar shell works well if you've got the cash for a high end bag.

As for reducing condensation problems, if it's significantly below freezing, a vapor barrier liner works well to keep moisture from your body condensing on the shell, as does adding a W/B bivy to your non-treated bag shell.

In cold weather I like to lay my Polarguard jacket on top of my sleeping bag which adds warmth, and so vapor condenses on the jacket instead of the bag. Keeps my down bag much drier, and the jacket dries WAY faster than down. I've used my 32 degree down bag into the single digits with a vapor barrier liner and my synthetic jacket on top with virtually zero condensation, and warm enough to sleep half decently.

[vaporjourney]

I'm surprised when I just looked at the Western Mountaineering site, that they don't mention any DWR material/treatment in their ultralite bag. Aren't they supposed to be some of the best in the market? I like this topic, I still need a winter bag and tarptent, and would get a Rainbow or Lunar Solo if I werent' so damn worried about condensation.

[StarLyte]

Thanks for the info Footslogger (post #7) !!

[Footslogger]

I still need a winter bag and tarptent, and would get a Rainbow or Lunar Solo if I werent' so damn worried about condensation.

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For what it's worth ...I went hiking on the Continental Divide last weekend. Daytime temps were in the high 70's. By the time the sun went behind the trees the temps had dropped into the 50's. Around 7 PM the clouds came in, the bottom dropped out in terms of temps and we got a nasty 3 - 4 hour thunder storm.

Point being ...I was inside my Lunar Solo-e during the biggest temp drop and the rain. I had absolutely NO leakage from outside and only modest condensation on the inside of the tent. The foot end of my sleeping bag had noticeable moisture on it but the DWR coating kept it from soaking through and causing the down to matt.

Now ...I can't comment on the WM bags (personally I'd call their CS department and ask) but I can tell you that aftermarket DWR treatment DOES work. Also, a little condensation is a small price to pay for a tent that weighs half of it's double wall counterparts (at least in my experience and opinion).

You'll fare well with either the Rainbow or the Lunar Solo

'Slogger

[hopefulhiker]

At the halfway point on the AT, I watched this presentation by a nature professor and photogropher. He explained to me about condensation. If you try to keep the tent somewhat ventilated and sleep a little cooler, don't bundle up so much, You will stay dry as a bone in a single wall tent. Condensation is caused by a really big temperature difference. My sleeping bag had a pertex shell so it didn't get too wet. I used down the whole time. Was only really cold when I got caught in that big snow right after Hot Springs last year. Everyone took a zero in a shelter.