Czech army sleeping bag and condensation

[rorymax]

Hi all,

A friend asked me this today "don't those water resistant bivi bag type sleeping systems cause moisture to develop from body perspiration, and consequently make one wet when sleeping?"

http://www.cheaperthandirt.com/product/MLT-4951

The outer shell is not as far as I know a breathable membrane as in gore-tex type products.

I could not give an informed answer to his question, but it seems a valid one.

Can anyone advise please.

Thanks,

rorymax

 

[Macaroon]

I've never had condensation problems with my one; but condensation is one of those multi-factoral things that are difficult to make hard and fast rules for. It'll always depend on so many different things happening in a given set of circumstances...............

I've used my one in some very cold and damp air conditions with a jungle bag and a woolen blanket with ccf mat inside and I've always been dry inside the thing; the top of the cover is a little breathable in my opinion, and it'd be underneath it that I'd expect to find condensation if it was left in situ for any length of time. I hope this helps a little

 

[rorymax]

Thank you Macaroon,

As someone who has used the item under different conditions, your comments are very much appreciated and valued.

Thank you.

rorymax

 

[jimbo75]

I used my Czech bedroll with my sleeping bag inside and on a raised camp bed at the last meet I went to...
the first night was quite warm and no probs... The following night the temp dropped by about 8-9 degrees, and i had a rough night due to condensation and cold strike!
im going to try a matt to insulate my body heat from the cold against the camp bed next time.. But I'm sure the bivvy bag was causing some condensation.
i think the uk damp and wet conditions are difficult to eliminate condensation regardless of sleep system.
ive had problems with other brand bivvy bags also.
i guess it's just a case of experimentation.
I prefer cold camping, but it is very frustrating when you think you've cracked it with your sleep system and then you wake up in the middle of the night cold and damp!

 

[rorymax]

Thank you jimbo75,

Actual experience of use is very helpful, it is interesting to note your comments on the outcomes under different conditions and your experiences with various other bivy bags.

Thanks again friend.

rorymax

 

[Angry Pirate]

i think the uk damp and wet conditions are difficult to eliminate condensation regardless of sleep system.
ive had problems with other brand bivvy bags also.

I've had the same problem with bivi bags. I have an issue goretex bag and a lightweight Rab survival zone. I have tended to use the Rab bivi as it is much lighter but as it relies on a coating rather than a membrane it is less breathable than the goretex. I used it in January biviing on the north face car park at Ben Nevis. It was relatively mild and drizzly and in the morning my down bag was soggy from condensation. For one night it was fine but I wouldn't have wanted to bivi the following night.
The main issue is you need a good temperature difference to "drive" the moisture through and a good sleeping bag will insulate you well enough to stop the inside of the bivi warming up. Then the water vapour condenses.
Now I use the goretex bivi and so far it's been much better thiugh I haven't like for like tested it yet!