Condensation and down bags

[Surrey_Andy]

So I am just back from a weekend in the beacons that saw me thoroughly test my new Rab ridge raider.

Although new to bivying, I did my research before purchasing and was aware that there was going to be a level of condensation involved.

True to form between the camps at the bottom of river bearing valleys, and the general welsh rain/drizzle/cloud base, i did experience moisture on the internal shelter walls.

Given the tight space of the ridge raider, this inevitably led to a transfer of the moisture to the outer surface of my down sleeping bag.

Today I checked and the outer surface is not listed as waterproof, and the down insulation is not specced as hydrophobic. However I didn't notice a discernable drop in performance across the weekend (admittedly not the coldest weeks I have done).

So the question is how much is this an issue?

Could I expect a short term drop in performance if it were colder? Is there an issue where the moisture accumulates over a trip to diminish the insulating value? And am I running the risk of longer term damage to the down if I keep exposing it to the moisture?

I have been back through the forums but could only find discussions about how to mitigate condensation.

 

[Mole]

It's fine as long as you dry it as soon as you can.

That might even mean packing it away damp, then at camp /bivi once in bed, the bag drying on you with body warmth only to end up damp again by next morning. It's no big deal IME. Done it loads of times. Never had hydrophobic down. And only my 4 season bag I no longer own had a waterproof fabric.

After all, you can wash a down bag by full submersion with no ill effects? So a little dampness now and then won't hurt as long as you dry it out. Some folk blow it all out of proportion as an issue.

Obviously if it's soaked through, or freezing cold conditions and/or just not dryable, then you'll need to take more drastic drying action.

 

[BogTrotter]

If you suspect any chance of moisture transfer to your sleeping bag, a dose of Down Proof by Nikwax mitigates any potential problems. It does work.

 

[old-skool-lite]

If you suspect any chance of moisture transfer to your sleeping bag, a dose of Down Proof by Nikwax mitigates any potential problems. It does work.

Not recommended on high fill power bags ie 1000fp. Rab don't treat their down at that standard & PHD don't recommend it. The more fragile down tendrils at that fill power can be damaged by the coating.

 

[Robert P]

The will be no longer term harm if the bag gets wet, but it is important to dry it out fully when you get home.
The will be some loss of performance if the bag gets wetter and wetter over successive days: I tend to find it is difficult to avoid the foot box getting wet (in a tent) during winter trips, but it hasn't yet been too much of a problem.

 

[BogTrotter]

My RAB and PHD and Cumulus all work fine with the treatment. But they’re only 900fp though. My winter North Face goose down will be getting the treatment too. ME don’t recommend or even supply hydrophobic down but they must add a DWR to their covers as water or condensation sits nicely on their surfaces.

I’m happy doubling up with Down Proof as well as an additional breathable DWR since keeping it all dry is the key factor in preventing failure to moisture penetration or even invisible moisture accumulation under windproof covers via evaporation.

I will even use a sacrificial overbag in the most challenging or suspicious conditions to make sure the waterproofing doesn’t even need to be tested.

YMMV.

 

[Jww]

Only 900 that's the highest I have lol

All my bags are nickwax and they seem fine I've been damp but never cold

 

[BogTrotter]

Only 900 that's the highest I have lol

All my bags are nickwax and they seem fine I've been damp but never cold

Realistically it’s what most will have. If you’re packing 1000fp you’ll most likely also be using a vapour barrier and not sleeping in a Ridge Raider.

The Ridge Raider, I found, didn’t live up to expectations and was probably the tiniest of hooped bivvies I’ve ever used. The condensation in this example doesn’t surprise me.

If your down sleeping bag isn’t waterproofed and you’re using it in a bivvy, then you should expect it to get wet. Wet down does compromise warmth.

 

[Teepee]

Any insulation in bivvy bags usually means some dampness.

What Mole said, it's not a big issue and often not hard to dry out.

If I know there is a good chance of some persistent dampness, a Nalgene hot water bottle to dry it is highly effective.

 

[Mole]

I had a Ridge Raider for a few years. Mine was the Rab version with eVent Fabric.

(Original Outdoor Designs version was goretex I think, and the current version uses Pertex Shield Air).

I'd say it was as breathable as any waterproof bivis get. (I've had about 14!).
The only more breathable option really is to have a bivi fully made of breathable fabric and have your mat outside the bivi.

I used the RR once continually for 7 nights July 2018 on the Two Moors Way. Rained constantly all night 1, showers night 2 and dry the next 5. Had quite a damp footbox night 1, but that was as bad as it got.

I sold it a couple of years later as it wasn't getting used very often, and I preferred the greater leg/foot room of an army bivi, which weighs less and, I found the RR harder to enter/exit compared to just a loose simple bag. I think the Ridge Master with it's side zip is a more user friendly design, but it's a silly weight then.

I used a microtarp if rainy even with the RR, so the hoop wasn't really that useful either. And I felt with a hoop, it degraded the "bivi experience" as it restricts movement and really interferes with the views.

 

[Surrey_Andy]

Thank you for the collective knowledge/experience of the forum.

I found that the bag dried fairly well day to day, and once I returned home I aired it fully so if there is no longer term damage I am fairly happy having read the replies. However I appreciate the nikwax recommendation, that is something I will consider.

Regarding the RR itself, I am still to be fully convinced. This trip was the opposite of ideal for a bivvy, where my dreams of star gazing through the bug net were replaced with driving rain! I have another trip upcoming that could be more suited (hopefully better weather, and with camps at elevation rather than wet valley floors). I really want to like the RR so hoping that those conditions suit it better.

 

[Surrey_Andy]

To update on this, I have enjoyed a number of further trips with the ridge raider, eventually adopting a tarp setup to enable me to maximise the ventilation though the bivy to manage the condensation.



Whilst it makes getting in and out even more of a contortion act, it provides shelter from rain allowing me to leave the outer down all night, as well as a bonus "vestibule" for storing gear and boot overnight.