Topic

Condensation . . . a foolish obsession?


Forum Posting

A Membership is required to post in the forums. Login or become a member to post in the member forums!

Home Forums Gear Forums Gear (General) Condensation . . . a foolish obsession?

Viewing 25 posts - 1 through 25 (of 30 total)
  • Author
    Posts
  • #3536613
    Duane Hall
    BPL Member

    @pkh

    Locale: Nova Scotia

    For those of us who occasionally obsess or at least worry about tent ventilation and condensation, a timely reminder.  It’s just simple physics and sometimes there is nothing we can do about it.  Last night I rigged my cuben flat tarp over my bug bivy . . . a test pitch, nothing more; I didn’t even spend the night in the bivy.   It was a cold, clear, still night with temperatures falling to near frost levels in the morning.  The grass was soaked, and both the outer and inner surfaces of the tarp were covered in dew . . . condensation, in other words.  The tarp set-up of course, was the ultimate in perfect ventilation, and there was nothing that could be done to prevent this.  It’s just the way it is sometimes :)

    #3536614
    JCH
    BPL Member

    @pastyj-2-2

    In other words, if the leaves, grass, bushes, ground, etc. are wet in the morning…your gear will be wet :)  Adopt nature’s strategy and deal with it.

    #3536616
    James Marco
    BPL Member

    @jamesdmarco

    Locale: Finger Lakes

    Yeah, at times there is nothing you can do. You simply have to generate less Relative Humidity inside the tent/tarp than outside it.

    Inside heat is the usual method to reduce the RH. A candle, your body, etc are all heat producers. Dry, heat will let more moisture dissolve into the air. But, most heat producers also produce water vapor adding to the interior humidity.

    Ventilation is the other method. This will exchange interior air (heat and moisture) with outside air. Under most conditions this works OK, but under your conditions, it won’t do much.

    Unfortunately, cuben conducts heat a bit better than nylon. So, it is hard to hold a heat “bubble” inside. Typically, you need a 1-3 degree difference between inside and outside air, assuming you hold the humidity constant. If you sleep under the tarp, you also add humidity soo, this often fails as a good method.

    As you say, it is often impossible under some conditions to avoid condensation. But, I have noticed my bag remains dry, even during a rainstorm, despite condensation on the tarp. The trick is managing the condensation and getting it to run off.

    #3536620
    Brad P
    Spectator

    @brawndo

    Would putting your sleeping bag inside a large trash bag be a lightweight means to keep the bag dry while sleeping in such conditions?

    #3536624
    Ken Thompson
    BPL Member

    @here

    Locale: Right there

    You’ll soak it from within if the bag can’t breathe

    #3536629
    Jerry Adams
    BPL Member

    @retiredjerry

    Locale: Oregon and Washington

    If it’s clear, your tent fabric will cool maybe 10 degrees from radiative heat loss

    Because of radiative heat loss, it cools everywhere until the RH reaches 100%, but your tent fabric will be 10 degrees cooler.

    There’s no way to prevent condensation in this case.  If you just hang a piece of fabric out with perfect ventilation it will still get condensation

    If you set up under a tree so you see no clear sky, it’s much better, although if it’s 100% RH you’ll still get some condensation

    #3536685
    Eric Blumensaadt
    BPL Member

    @danepacker

    Locale: Mojave Desert

    Tarptent’s more recent offerings seem to deal with the ventilation problem as well as anyone and better than most.

    Both my Scarp 2 and Moment DW have “eyelid” vents at the peak area and have low vents at the ends which gives a nice natural upward convection air flow. This gets moist air out about as well as possible but there are always cold/damp conditions that overwhelm it.

    Any tent with two opposing doors can vent well if there is not a windstorm during rain or snowstorms. My TT tents’ doors have mesh in the top 1/3 which, again, helps with the natural convection of rising body heat.

    BTW, I’ve found that most tent floor tub “walls” tend to collect condensation at times, especially in winter in the form of frost. To keep the foot of my bag dry I zip up my WPB parkas and slide them up over the foot of my bag.A bit more warmth and good moisture protection.

     

    #3536691
    Jerry Adams
    BPL Member

    @retiredjerry

    Locale: Oregon and Washington

    Those small vents don’t do a lot in my experience

    Two opposing doors is good.  Opening one door completely is pretty good.

    #3536739
    Todd T
    BPL Member

    @texasbb

    Locale: Pacific Northwest

    Basically, if the temperature at the surface of the fly is below the dewpoint, there will be condensation. Lots of things affect those two variables, including ventilation, but in my experience the two most important things one can do to minimize condensation are (1) set up under a forest canopy on clear nights, and (2) don’t set up where outside sources add moisture to your tent. W.r.t. the latter, it means stay a good distance from water and don’t set up on vegetation or wet ground. A third thing would be to have a tent configured for cross-ventilation, but that doesn’t help much on still nights.

    #3536749
    Franco Darioli
    Spectator

    @franco

    Locale: Gauche, CU.

    Often when people comment that they don’t get condensation on their tent , what they really mean is : I haven’t camped in the same situation as you have.

    (ever noticed that after reporting heavy condensations inside a tent the next comment sometime is : all the other tents nearby also…)

    #3536761
    James Marco
    BPL Member

    @jamesdmarco

    Locale: Finger Lakes

    Yeah, I agree with Jerry. Small vents at 100% RH and still conditions don’t help enough to bother with. Though, in cold weather (ie <40F) you can place a small candle lantern under the peak vent to drive the ventilation.

    #3536767
    Rex Sanders
    BPL Member

    @rex

    Tent condensation in the coastal mountains of central / northern California happens most of the time, no matter where or when you camp.

    IME, silnylon is both a condensation and dirt magnet, resulting in a much wetter, heavier, and dirtier tent in the morning, even if I wipe it down repeatedly while constantly wringing out the towel.

    Is DCF / Cuben much better? Are any other lightweight fabrics much better?

    — Rex

    #3536782
    Pigeon
    BPL Member

    @popeye

    Would doors that expose some of the bathtub floor offer much more ventilation? I’m thinking about hot nights more than moisture management. I know they let in rain, by it’s not usually raining.

    #3536852
    Seth R
    BPL Member

    @lerxst

    Locale: Northeast

    I have abandoned the fight and wave a pack towel in surrender each morning.

    #3536869
    Duane Hall
    BPL Member

    @pkh

    Locale: Nova Scotia

    Yup, there are times when a good pack towel in the final solution :)

    #3536883
    Jerry Adams
    BPL Member

    @retiredjerry

    Locale: Oregon and Washington

    ” I know they let in rain, by it’s not usually raining.”

    Yeah, I leave door open and close it only as much as required to keep rain out.  Wind is also a factor, if it’s raining and not windy I can leave door open.

    #3536920
    andrew mitchell
    BPL Member

    @brocc0

    I have a cuben tent and rain jacket. Because they do not absorb water unlike sil nylon, I can just wipe it dry in the AM and pack it dry. The tent condenses a little; the jacket none. I am amazed and happy. Sil nylon is fine in low rain..

    #3536944
    Eric Blumensaadt
    BPL Member

    @danepacker

    Locale: Mojave Desert

    Being a “belt & suspenders” type I’ve re-coated both my Moment DW and Scarp 2 with a 5:1 mix of, respectively, “odorless” mineral spirits and GE clear Silicon II. Shaken VERY well in a 1 pint jar and applied with a small (6″), short knapped roller. I applied the mix in 2 ft. square sections and immediately wiped each section down with a sturdy blue paper shop towel for even coating.

    That treatment has added maybe an ounce or so to each tent but they will never “mist thru”.

    HOWEVER, I later discovered that Henry Shires’ more recent Tarptents (say since about 2010) have a heavier silicone  coating and do not need this treatment for even monsoon rains. Nobody has ever reported “mist thru” since Henry changed to the heavier coating. And I suspect most “mist thru” reports actually came from condensation being knocked from the inside of the flys by the heavy rain. Jus’ sayin’…

    Wish I’d known that before I treated my own Tarptents.

    #3536949
    Dale Wambaugh
    BPL Member

    @dwambaugh

    Locale: Pacific Northwest

    I’ve spent most of my life living at the dew point! Ventilation will help keep your breath and body moisture from adding to the fray. When you are camping in cool high humidity conditions, dew happens. A bivy with a breathable DWR top and waterproof bottom can help. A sponge, bandana or microfiber cloth can be used to bail things out. Having a shelter big enough to avoid touching the fabric really helps. In the old days with wax treated cotton tents, you didn’t dare touch the fabric as that it is where it would drip and of course that was right over your face.

    Camping away from lakes will help avoid the higher humidity. I’ve never been wetter than when sleeping under the stars on grass next to a beach. It was such a lovely summer night when I dropped off to sleep and like waking up in a car wash at 5AM.

    I’ve woken up to dew frozen to the inside and outside of the tent when the temperature continued to drop past the dew point and freezing. Like a big ripstop popsicle to pack up in the morning and all the brush and grass in the camp was the same way. Hiking brushy salal trails early in the morning dew might require rain pants.

    #3537807
    Marcello
    BPL Member

    @alvisim1

    Locale: Chester Springs PA....Near King Of Prussia

    Don’t worry if you get a little wet. You wont melt…unless you are made of sugar.

    Of course, If it’s winter tenting you will get a little frost. It shakes off easily when breaking down.

    Happy trails to all!

     

    #3537810
    Jerry Adams
    BPL Member

    @retiredjerry

    Locale: Oregon and Washington

    frost on inside of tent isn’t too bad, it won’t soak into you if you brush against it

    shake tent off before packing.  it helps if it warms so that the ice starts melting

    #3539101
    Jacob
    BPL Member

    @jakeyjohn1

    How do hot tents handle fog, excessive dew, and other extreme condensation scenarios?

    #3539103
    Dale Wambaugh
    BPL Member

    @dwambaugh

    Locale: Pacific Northwest

    Wood heat is super dry. They make iron kettles to keep on a wood stove to keep it from getting too dry. Having lived in a couple places with wood-only heating, you can feel it coming in the door.

    Of course the challenge is getting it light for backpacking use.

    #3539760
    Eric Blumensaadt
    BPL Member

    @danepacker

    Locale: Mojave Desert

    Dale,

    “…you can feel it coming in the door.” (cold air)

    The key to efficient wood burning stoves is to bring ALL the combustion air into the fire box via a pipe from the fire box through the house or under tent wall from the outside.

    This keeps the stove from sucking up warmed air and reduces fuel consumption quite a bit.

    #3539768
    Dale Wambaugh
    BPL Member

    @dwambaugh

    Locale: Pacific Northwest

    No, I meant you can feel the dryness when coming inside. Half the year here is 45f, 90% humidity and overcast. Can I send you some moss salad with mold and algae dressing?

Viewing 25 posts - 1 through 25 (of 30 total)
  • You must be logged in to reply to this topic.
Forum Posting

A Membership is required to post in the forums. Login or become a member to post in the member forums!

Get the Newsletter

Get our free Handbook and Receive our weekly newsletter to see what's new at Backpacking Light!

Gear Research & Discovery Tools


Loading...