Go Back  Bike Forums > Bike Forums > Touring
Reload this Page >

How to avoid damp duvet in the morning?

Notices
Touring Have a dream to ride a bike across your state, across the country, or around the world? Self-contained or fully supported? Trade ideas, adventures, and more in our bicycle touring forum.

How to avoid damp duvet in the morning?

Old 08-22-10, 02:35 PM
  #1  
irpheus
Explorer
Thread Starter
 
Join Date: Feb 2009
Posts: 90
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Likes: 0
Liked 1 Time in 1 Post
How to avoid damp duvet in the morning?

Hey bikers,

I currently sleep in a tent in the garden - sort of as a preparation for a longer touring this autumn. I use my duvet to cover me during the night, however, have noticed that no matter the weather it is always damp on the exterior side in the morning.

I have an MSR Hubba Hubba tent and find it to ventilate quite reasonably.

I'm wondering what will happen when riding longer tours using the same sleeping bag (down sleeping bag). Will it always be damp in the morning and need some time to dry up? What if it rains or the weather is humid...?

Anyone have experience/practical advice on this?

Thanks for reading ;-)

Jesper
irpheus is offline  
Old 08-22-10, 03:51 PM
  #2  
wahoonc
Membership Not Required
 
wahoonc's Avatar
 
Join Date: Jan 2005
Location: On the road-USA
Posts: 16,855

Bikes: Giant Excursion, Raleigh Sports, Raleigh R.S.W. Compact, Motobecane? and about 20 more! OMG

Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 70 Post(s)
Likes: 0
Liked 15 Times in 14 Posts
Depends on the humidity in the area you are. I use a tent with screen walls and a rain fly. I chose synthetic for my sleeping bag because of moisture. When camping at lower elevations along the east coast of the US I get some dampness almost every night. If the morning dawns bright and cheerful I will lay the bag out to dry a bit and pack it last. If it is a wet day, I just pack the bag and hope for the best. If it gets really wet, I will dry it at the first chance I get, whether by sunlight or other means.

Aaron
__________________
Webshots is bailing out, if you find any of my posts with corrupt picture files and want to see them corrected please let me know. :(

ISO: A late 1980's Giant Iguana MTB frameset (or complete bike) 23" Red with yellow graphics.

"Cycling should be a way of life, not a hobby.
RIDE, YOU FOOL, RIDE!"
_Nicodemus

"Steel: nearly a thousand years of metallurgical development
Aluminum: barely a hundred
Which one would you rather have under your butt at 30mph?"
_krazygluon
wahoonc is offline  
Old 08-22-10, 03:55 PM
  #3  
drmweaver2
Senior Member
 
Join Date: Jun 2010
Posts: 817
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 2 Times in 1 Post
Dampness on the exterior of the sleeping bag inside a tent - when it hasn't been rained or dripped on - is a function of water vapor condensation.

From multiple wikipedia pages: The dew point is the temperature at which a given parcel of humid air must be cooled, at constant barometric, for water vapor to condense into water. The dew point is associated with relative humidity. A high relative humidity indicates that the dew point is closer to the current air temperature. Relative humidity of 100% indicates the dew point is equal to the current temperature and the air is maximally saturated with water. When the dew point remains constant and temperature increases, relative humidity will decrease.

To get specifically to the OP's question, under the proper temperature/pressure conditions, it's easy for dew to form in still air, far less so in constant breezes/winds greater than 5mph. But wind is rarely "constant" despite us thinking our tents are "well ventilated". In addition, we affect the relative humidity inside the tent by water vapor from our breathing and as a heat source under/inside the sleeping bag itself.

So, a light dampness on the exterior of the sleeping bag is relatively normal depending on altitude and local weather conditions/season. I've never had dampness on a bag in the morning in the Southwestern US states at low altitude; I assume it evaporated before I awakened. Otoh, it's fairly common in Louisiana 10 months of the year - but it usually dries out/evaporates in 5-10 mins, especially when I put the bag directly in sunlight while eating breakfast.

One other thing, the direction in which the tent faces can definitely affect condensation inside as will tent fly design. Tunnel tents, A-frames and bivy's that have end-only venting must be pitched with their openings into the wind for maximum ventilation. Dome tents and tents ventilation on all sides whose flys do not extend to the ground are less sensitive to wind direction with respect to ventilation/interior air movement. (Note that maximum ventilation is not always desirable - especially during rainstorms!)
drmweaver2 is offline  
Old 08-23-10, 02:06 AM
  #4  
irpheus
Explorer
Thread Starter
 
Join Date: Feb 2009
Posts: 90
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Hi both of you :-)

& thanks for your replies & suggestions. @wahoonc: I hope to find many mornings dawning bright & cheerful, not just because of the drying effect but just to experience nature like that ;-)

@drmweaver2: I hadn't considered the orientation of the tent as affecting the amount of ventilation inside the tent, so thanks for mentioning this.

What really surprises me, though, is that it's so noticable lately. I only recently bought the Hubba Hubba tent (earlier had a a quite cheap, yet very functional supermarket tent) and moisture drops clearly forms on the inside of the fly during the night so I'm wondering if the fly could be less breathable than the fly on my previous tent ...? I've used the same duvet in both tents, and in more or less the same nature conditions, & in my memory it didn't use to get that damp.

Anyone have tried to e.g. hang a "moisture collecting device" in the tent?

Hmmm... thanks again for your replies!

Cheers,

Jesper
irpheus is offline  
Old 08-23-10, 05:52 AM
  #5  
drmweaver2
Senior Member
 
Join Date: Jun 2010
Posts: 817
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 2 Times in 1 Post
Something you could do to try to "establish a new norm" for your expectations with the new tent:
1. Set up the tent, including fly, in the backyard "normally" - facing into the wind. Try to pick an open spot with no overhead branches. No need to ask for sap drippings on the new tent.
2. Above the tent's fly, maybe 2 inches, rig a "Secondary fly" using plastic trash bags and twine. The idea is simply to prevent the tent's "real" fly from being "needed" - though you "need" it set up for this experiment. This doesn't need to be "form fitting" - just enough that straight down rain wouldn't hit the tent's fly and so as to provide some area of stagnant/still air around the outside of the "real fly". Leave openings for the doorways if you decide to try to "form fit" the secondary.
3. Let stand overnight (or two) - doors & vents/no-see-um screens totally open.
4. Check in the morning for dampness/condensation - real early, say 5:30am before the sun really comes/warms up.
5. Open the doors/vents completely to dry out the each day.
6. Then, close the doors, vents and screens totally for another couple nights and repeat steps 3 - 5.
7. Compare the results. That should establish the "tent only 'new' norm" for your local area.

You should be able to extrapolate what will happen "on tour" from there.

PS. While you have the tent set up for this experiment, may as well get out the seam sealer and do your thing for when it rains.

Last edited by drmweaver2; 08-23-10 at 08:15 AM. Reason: spelling/punctuation correction
drmweaver2 is offline  
Old 08-23-10, 07:29 AM
  #6  
LHT in Madison
Senior Member
 
Join Date: Jan 2010
Location: Madison, WI
Posts: 100

Bikes: 2009 Thorn Sherpa, 2004 Surly LHT, 1961 Ideor, et al.

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
For longer trips I use a synthetic sleeping bag and only use my down bags on shorter trips or trips where I expect to be able to dry out the bag regularly. Most of my camping is canoe or kayak trips where I am near a shore.

Even my synthetic bags get aired out regularly in late afternoon sun by hanging from a line from a tree branch or on laid out on top of the tent. I try to do this every 3 to 5 days whether the bag feels like it needs it or not.

Some (and possibly most?) of the moisture is from your skin when you are in the tent because even if you are not overly warm, you are always sweating a small bit of moisture. The moisture will migrate away from your skin in vapor phase (in the air) through the bag insulation towards the colder outside of the bag where it can condense where the temperature of the air in the insulation or on th ebag surface reaches the dew point.

I have camped in winter with down bags in northern Minnesota, Wisconsin and Michigan UP under a tarp instead of in a tent. The tarp does not restrict air flow, thus any moisture in the air from breathing quickly disipates instead of being trapped inside of a tent. Yet, I have often found my bag to be quite damp after the trip when I bring the bag indoors, the moisture was from sweat even though it was never that warm inside of the bag and I never noticed feeling damp in the bag. In this case, all of the moisture in the bag was from skin, not from breathing. Some winter campers use a vapor barrier liner to prevent skin moisture from getting into the bag insulation.

Bottom line is that you should plan to regularly dry out your bag on tour and if it is problematic you may need a synthetic bag instead of down.
LHT in Madison is offline  
Old 08-23-10, 08:44 AM
  #7  
valygrl
Senior Member
 
Join Date: Jul 2003
Location: Boulder, CO
Posts: 8,546
Mentioned: 83 Post(s)
Tagged: 0 Thread(s)
Quoted: 163 Post(s)
Likes: 0
Liked 2 Times in 2 Posts
Are you camping on a watered lawn? That makes a huge difference.
valygrl is offline  
Old 08-23-10, 09:16 AM
  #8  
truman
It's true, man.
 
Join Date: Aug 2005
Location: North Texas
Posts: 2,726

Bikes: Cannondale T1000, Inbred SS 29er, Supercaliber 29er, Crescent Mark XX, Burley Rumba Tandem

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
I find it helps to keep my bedding dry if I go #1 before bedtime
truman is offline  
Old 08-23-10, 09:21 AM
  #9  
Carbonfiberboy 
just another gosling
 
Carbonfiberboy's Avatar
 
Join Date: Feb 2007
Location: Everett, WA
Posts: 19,500

Bikes: CoMo Speedster 2003, Trek 5200, CAAD 9, Fred 2004

Mentioned: 115 Post(s)
Tagged: 0 Thread(s)
Quoted: 3872 Post(s)
Liked 1,920 Times in 1,369 Posts
Yes, a waterproof fly will collect condensation on the inside. In a well-designed tent, the condensation just runs down the fly and doesn't drip on the tent. We try to pitch where the morning sun will hit the tent. If it doesn't, or no sun, we just shake the fly really well before packing it up, then try to dry it when setting up the next camp.

Down bag with nylon cover fixes dampness problem. Down dries very quickly. It and the cover allow the moisture to go right though without staying behind. In 35 years of backpacking down low and in the high mountains, including living in the tent for days at a time during rainstorms, snow, hail, below freezing, never had a problem with it. Never tour or backpack with anything made of cotton.
Carbonfiberboy is offline  
Old 08-23-10, 10:58 AM
  #10  
drmweaver2
Senior Member
 
Join Date: Jun 2010
Posts: 817
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 2 Times in 1 Post
Originally Posted by Carbonfiberboy
Down dries very quickly.
Um, no. Down itself does NOT dry quickly. The sleeping bag cover may dry quickly, but down itself is notorious for drying slowly while inside bags, pillow cases, etc.
drmweaver2 is offline  
Old 08-23-10, 11:16 AM
  #11  
Carbonfiberboy 
just another gosling
 
Carbonfiberboy's Avatar
 
Join Date: Feb 2007
Location: Everett, WA
Posts: 19,500

Bikes: CoMo Speedster 2003, Trek 5200, CAAD 9, Fred 2004

Mentioned: 115 Post(s)
Tagged: 0 Thread(s)
Quoted: 3872 Post(s)
Liked 1,920 Times in 1,369 Posts
^ Wrong.
Been using down bags for 49 years. Your experience?
Carbonfiberboy is offline  
Old 08-23-10, 11:52 AM
  #12  
Roberto C.
Roberto C.
 
Join Date: Mar 2010
Posts: 11
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by Carbonfiberboy
^ Wrong.
Been using down bags for 49 years. Your experience?
It is generally accepted that synthetic bags are better for wet conditions. Down has lots of other great properties, but it does not dry as quickly.

https://www.sierratradingpost.com/lp2...tic-guide.html

Check the "Cons" section for down. A quick Google search will find tons of of other links that all same the same thing, namely that down dries slowly compared to synthetic. It is true that down wicks away moisture from the body, but if it gets wet, look out.
Roberto C. is offline  
Old 08-23-10, 12:18 PM
  #13  
irpheus
Explorer
Thread Starter
 
Join Date: Feb 2009
Posts: 90
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Hello

- appreciate your feedback & experiences

@drmweaver2: Thanks for outlining a test procedure for finding out how my new tent fares in terms of condensation. It's a bit beyond what I have in mind for testing but I get the idea of establishing a baseline for the tent alone. And will consider the seam sealer

It makes me wonder, though, if any of you have experience with breathable light-weight fly materials?

The Hubba Hubba itself is made from "ripstop nylon 6 1500mm Polyurethane & Silicone Coated" which I reckon is not really breathable.

It seems to me that there are varying experiences with down being damp. My own experience, compared with other people, is that I tend to perspire more than average. On the other hand I really like down and natural materials so will have to think of something here. Any of you know of a source of superb down? Just might do my own duvet/sleeping bag.

In terms of understanding how/why my duvet becomes damp I would say that I know have a good picture of the mechanisms and also how you come about reducing the phenomenon. Thanks again for sharing your experience & suggestions

Greetings from a rainy Denmark,

Jesper
irpheus is offline  
Old 08-23-10, 12:22 PM
  #14  
NoGaBiker
But wait... I AM the man.
 
NoGaBiker's Avatar
 
Join Date: May 2006
Location: No Ga.
Posts: 641

Bikes: Merlin Extralight DA, 1982 Peugeot CFX-10 Campy NR, 7 Cruisers kept at beach, Raleigh Passage 4.0 hybrid, Marin Commuter with racks and bags

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Originally Posted by irpheus
I only recently bought the Hubba Hubba tent and moisture drops clearly forms on the inside of the fly during the night so I'm wondering if the fly could be less breathable than the fly on my previous tent ...? Jesper
Hi Jesper

Just to clarify, flys are not at all breathable -- they are completely waterproof, not breathable. That's why they exist.

Double wall tents (tents with a fly) work on the principle that moisture vapor escapes through the permeable tent walls then hits the underside of the impermeable fly, where it stops rising, cools off and becomes liquid (condensation.) It then tries to fall back on you but finds itself thwarted by the presence of the tent wall, which is not sufficiently "waterproof" to stop rain, but will stop the little drips of condensation that fall back onto it. It generally does this, though, by means of the surface tension of the water drops causing them to slide right down the outside of the tent wall and land harmlessly on the grass.

So often, if you touch the tent walls from the inside you will disturb those drops, the tension is broken, and they bleed right through the tent wall fabric and onto your bag.

Don't know if the size of your hubba hubba is such that you're bumping it a lot more in the night than you used to or not, but that's a possibility.

(Another type tent is the single wall, which has no rain fly. It utilizes a waterproof/breathable fabric and works much like a goretex jacket -- vapor escapes but moisture can't get back through. I use one of these called the North Face Solo 1. It works great at altitude where it's cold and dry most of the time. I've not tried it in the southeast in summer, where the fabric would probably not be able to let enough moisture vapor out fast enough to keep the inside dry.)
NoGaBiker is offline  
Old 08-23-10, 12:24 PM
  #15  
fietsbob
Banned
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Posts: 43,598

Bikes: 8

Mentioned: 197 Post(s)
Tagged: 0 Thread(s)
Quoted: 7607 Post(s)
Liked 1,354 Times in 861 Posts
Hanging a Down bag in the nice weather and fluffing it every once in a while will dry it,
But you have to stay in one place to do that ...
OTOH a synthetic can be packed immediately , water dampness will make it a bit heavier , of course
but your body heat the next night will drive off that moisture if its not the same weather situation day after day.

Morning Dew point was the initial problem ..
fietsbob is offline  
Old 08-23-10, 12:38 PM
  #16  
irpheus
Explorer
Thread Starter
 
Join Date: Feb 2009
Posts: 90
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Likes: 0
Liked 1 Time in 1 Post
@NoGaBiker:
Don't know if the size of your hubba hubba is such that you're bumping it a lot more in the night than you used to or not, but that's a possibility.
. No, I don't think this is the issue, I guess it's condensation as described earlier by some of the others.

But thanks for replying ;-)

Jesper
irpheus is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
TimothyH
Touring
44
04-14-19 03:02 PM
Sharpshin
Touring
45
02-24-16 10:04 PM
12bar
Touring
36
02-07-13 12:27 PM
mthayer
Touring
29
12-29-10 01:58 AM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.