UKC

After kipping in a tent at 800m (in the lakes) at the weekend I woke up to a pretty damp down sleeping bag.

Reasons for it could be:

a) I was also using a bivvy bag (Rab Survival Zone about ten years old and I have treated it as it wasn't really keeping my old synthetic bag dry) so too warm;

b) I was pretty much over clothed cos it was fricking freezing and I obviously didn't want to get the chills so again too warm or;

c) a combo of a and b.

Any suggestions why it would have become damp other than those I've suggested and what to wear or not as the case maybe and so avoid the same occurrence?

Thanks

In reply to greylag:

My Rab Survival Zone isn't very breathable either; I usually have damp on the outside of my sleeping bag after using it. For the whole shebang though, it sounds like you were too hot. I have an uber-hot sleeping bag that is frankly overkill for the UK, but I'm too tight to buy something else. I usually wear just a thermal top in it, and unzip down to the middle of my torso. That works a treat, and when it is too cold I just zip it up more!

In reply to greylag:

Bivvy bag in a tent? Why?

In reply to greylag:

If you put a waterproof layer on top of your sleeping bag it will trap all the moisture from your body inside. If you are sleeping outside that's the price you pay for keeping the rain off. If you are sleeping in a tent it's not necessary or helpful.

In reply to AlanLittle:

I know, we were on damp ground (the best we could find at 1030pm in the dark!) and I wasn't convinced the wet wasn't going to seep through to the bag so used it as a precaution. It back fired!

In reply to greylag:

Clothing in sleeping bags is poor form.
The bag works by trapping your warmth.
If it's settling in old clothing it won't work as well especially if the clothings damp.
Perhaps you're a warm sleeper and didn't really need the clothing? Get in naked and do some exercises to warm the old bag up.
Also, leave a bit of a gap on your tent zip to allow damp air to escape.

In reply to greylag:

Next time put it over your sleeping mat instead.

In reply to Dave the Rave:

I agree but when it's the temps are below freezing and theres's a biting wind i's natural to jump in with a layer or two on and de-layer once you're satisfied you will be warm enough.

I did however, have less on the following night (lower down spot) with no bivvy bag and the bag didn't get damp which probably answered my own questions but I needed to hear it from someone else.

In reply to marsbar:

I was under the impression that a sleeping bag cover could be helpful for keeping condensation from breathing from making your bag damp, with this being more dampness than sweat would be?

Edit: Without using a sleeping bag cover, I've noticed I've had a damp down bag each morning when sleeping out in the cold during the winter.

In reply to greylag:

It's really easy when you are asleep for your breath to go at least in part into your bivvy bag - that contains huge amounts of water vapour and the big of your bag around the chest can get really wet that way. Unless it's actually raining or snow, making sure the bivvy bag isn't to close up to your face so as to catch your breath as your breath out is important, but if you move in your sleep, it can still happen really easily.

In reply to greylag:

I think you might have discovered about the dew point by experimentation....

B

In reply to greylag:

I was also camping in the Lakes on Saturday night, 840m, down bag, no bivi bag just tent. Note any dampness on the bag came from the frost build up on the inside of the tent brushing off onto the bag when moving around. Also sometimes the bag can feel damp when actually its just freezing cold!
Anyway as others have said using a bivi bag inside a tent is the cause of your problem! I like you, if still cold, put on layers and it helps keep me warmer, especially around the thighs which I have a pair of fleece shorts for sleeping in.

In reply to Dave the Rave:
Whether clothing works in sleeping bags all depends on the size of the bag compared to the person using it. As long as you aren't compressing the loft of the bag it will keep you warmer wearing clothes (whether this was a good thing in this case is another matter)

In reply to greylag:
I've had down bags damp out from both me being over hot and other times from dew settling in the tent.

I guess you have to bear in mind that if its humid outside the rab survival zone that the breath ability of it will reduce significantly as it will be relying on it being more humid inside the bag compared to outside to function. It could easily have been a combination of the two that caused the issue.

In reply to pass and peak:

And here was us [wishfully] thinking we'd be the only ones camping at that height... the stars were stunning!

When I sleep in the car (completely dry from the ground) I often get a wet sleeping bag around my feet. This also happens in a tent, but there it can be put down to condensation/leaking ground sheet etc. Also recently noticed it happens if I use the sleeping bag in someones house etc. It's my sweaty feet! I'm investigating vapour barrier liners when I'm planning on using the bag for more than a couple of nights.

In reply to NottsRich:
Yes. A vapour barrier will sort the problem. However you will stay warm, but also very clammy which is not pleasant. try not to breath into your bag and or bivvy bag as that will up the moisture content dramatically.

Those of us of a certain age who used to camp regularily in Scottish winters in class cotton tents such as the Arctic Guinea or Blacks Good Companions had little if any condensation issues, and we stayed warm and dry. Modern nylon tents are just large plastic bags that concentrate moisture.
In the 1980s we camped at Loch Morlich with a forecast temp of -25C. Our nylon tent iced up inside even before we got in it. We had a cold two nights due to condensation. Our friends in their Artic Guinea had zero condensation and stayed dry whereas our bags were losing loft dramatically. The good companion was straight back into use after that.

In reply to greylag:

Hi,

1 - you dont need a bivvy if you are already in a tent
2 - is your tent ventilated correctly ?
3 - if you do need to sleep in layers try Icebreaker base layers (100% Merino wool - naturally wicking and good warmth to weight)
4 - make sure there are no wet items of clothing within the tent itself
5 - did you get your bag wet unpacking your backpack ? (use dry bags to organise and keep all your kit dry within your backpack

hope this helps !

In reply to Root1:
Yep. These days in nylon tents it's really important to ensure perhaps better ventilation than one thinks necessary. If there isn't a cool breeze blowing over your head as you lay down then there ain't enough.