Condensation

Udders

Udders

A Needy Twat
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I know this time of year is the worst for condensation in tents, as I have experienced plenty of times, ( and I do know that ventilation is key ) but I saw someone the other day use a small bivi bag over the top top of their down sleeping bag ( in a tent I must add ) to keep the moisture off. Last week it was very cold and wet up in the Peak District where I was camping and even though my Rab Ascent 1100 down sleeping bag has a water repellent coating it still got damp to the touch. Does anyone else use a bivi bag over their sleeping bag and if so, does it work / make a big difference? :nenau
 
Camping at this time of year??? Bugger that!
 
I suppose most of the condensation is from breath so maybe the bivi bag is worth a shot ? (I appear to produce loads of condensation and imagine it would have a dire effect and make matters worse)
Good ventilation has been my only way (and making sure I get a tent that isn't just 10cm longer than me or I touch both ends and get soggy ends of the sleeping bag)
 
Udders I would have thought the mechanism of condensation is twofold.

1) You breathe out warm wet air that hits the tent fabric and forms droplets of water
2) You generate heat that warms the moist air in the tent that rises and forms droplets of water on contact with the tent fabric

The bivi would do two things, A) keep more of your heat in , reducing 2 above, second it would shed any droplets of water dripping of the roof of the tent caused by 1 above.

If I was going to use a bivi as well, I might be tempted to drop a season on the bag though, otherwise you might get too hot.

Just my ramblings not scientific….
 
OnHellas said:
Camping at this time of year??? Bugger that!
Click to expand...

Camping up mountains in the snow too! :thumb2 Stunning scenery and once you’re out of the cold wind blast not too cold either. Sort of. :D With the right kit it’s quite enjoyable. Hardly anyone else around too. :thumb2
 
steve hughes said:
Udders I would have thought the mechanism of condensation is twofold.

1) You breathe out warm wet air that hits the tent fabric and forms droplets of water
2) You generate heat that warms the moist air in the tent that rises and forms droplets of water on contact with the tent fabric

The bivi would do two things, A) keep more of your heat in , reducing 2 above, second it would shed any droplets of water dripping of the roof of the tent caused by 1 above.

If I was going to use a bivi as well, I might be tempted to drop a season on the bag though, otherwise you might get too hot.

Just my ramblings not scientific….
Click to expand...
That’s what I was thinking. I may get one and try it. I have 3 different down sleeping bags too so can use one of the less warm ones.
I just wasn’t sure where any moisture would go that may come from out of the sleeping bag. I’m guessing that if I get a good quality breathable bivi bag it would escape through that and not make things worse by getting trapped between layers? :nenau
 
For many years winter camping in the mountains I never found any issues with condensation in the tent and didn't have the space to consider taking a Gore-Tex bivvy bag as well as a tent. It was an either/or situation.

As you say ventilation is the key, but your sleeping bag will wick the moisture away from your body and it will condense on the outside of the sleeping bag as the air is colder there. A few times I woke up in the morning, warm and snug in my sleeping bag, but with ice on the outside of the bag.

I didn't have any issues with the sleeping bag getting wet, I aired it if I could (whilst away) but didn't do anything special.

I would suggest that if you are having condensation dripping inside your tent, you need to sort your tent ventilation better, be careful what and how you cook in the tent, if you do, and stop breathing during the night. :)

I wouldn't use a bivvy bag in the tent as you'll just end up in a pool of moisture which will cause problems with the loft in your bag.

My two penn'th :thumb2
 
It should work well. Quote a few people i watch on YT use the Bivi bag for that reason - keeps moisture off the sleeping Bag and helps to retain heat too. Doesn't need to anything super rugged, or fully designed to be a standalone system
 
I always thought and have watched a few videos on bivvy bags and they always mention that they get condensation inside the bivvy bag ,that maybe if they close the bag fully up , as has been said may be look at improving the ventilation in your tent .
 
I have 3 Hillebergs. Two of them are 4 season ground hugging ones but the Rogen does have “ lifted “ ends. Not had a problem with that one. It was particularly cold, wet and blooming windy when my sleeping bag got moist on the top! :D But that was with the Allak 3.
I’m just trying to find a way of keeping it completely dry in case I do a multi day walk and have no way of drying it out properly.
 
It’s simple, get away from the idea that you need to be as warm as possible and keep it down to remaining comfortable without generating enough heat to cause condensation.

Ventilation is key and if you’re not feeling a bit chilly you’re not ventilating the tent properly.
 
I've used a goretex bivi over a down bag many times with no moisture issues on the bag.
I've mainly done it in winter (Scotland) where your breath can freeze on the tent and rain down as ice crystals that would then melt on your down bag.
 
Another tip is that cotton tents with cotton flysheets don’t suffer from condensation. I shared my Force 10 tent with our Labrador between Xmas and new year and suffered from zero condensation but the downside is that a Force 10 is fucking heavy if you’re carrying it.

It probably helped that I broke the zip on my sleeping bag so certainly wasn’t sweating too much :D
 
I once camped in Inverness late in the year. It was cold. Ice on outside of the tent cold.
I thought i`d try and retain some heat by putting one of those emergency foil thermal blanket things over me in an attempt to stay warm.
When i awoke in the morning my sleeping bag was soaked through due to the condensation forming on the underside of it.
Fail.
 
AndyB_11 said:
It’s simple, get away from the idea that you need to be as warm as possible and keep it down to remaining comfortable without generating enough heat to cause condensation.

Ventilation is key and if you’re not feeling a bit chilly you’re not ventilating the tent properly.
Click to expand...

Precisely, ventilation is the only proper solution to condensation.
 
I've a light weight, synthetic quilt I throw over my sleeping bag, it's a Thermarest and would fasten to my old mat and cover, if I still used it.
If you're camping more than a few days in sub zero temps, perspiration freezing in the down becomes a problem if you've no way of warming it and airing it out. A VBL is the solution https://www.phdesigns.co.uk/vbl-vapour-barrier-liner-bag stops perspiration entering the down, PHD being the most expensive, high end manufacturers there is, but it's UK made.
 
dean0n0 said:
I've a light weight, synthetic quilt I throw over my sleeping bag, it's a Thermarest and would fasten to my old mat and cover, if I still used it.
If you're camping more than a few days in sub zero temps, perspiration freezing in the down becomes a problem if you've no way of warming it and airing it out. A VBL is the solution https://www.phdesigns.co.uk/vbl-vapour-barrier-liner-bag stops perspiration entering the down, PHD being the most expensive, high end manufacturers there is, but it's UK made.
Click to expand...

Ooh, there could be the answer! :thumb2 Great find! Sleeping bag liners and covers. Nice quality stuff there! :thumb2 Cheers.
 
I have an army surplus Gore-Tex bivi bag, which I bought second hand off with forum, within days of joining.

It is waterproof and acts as an excellent extra layer if you get a cold snap.
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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