Condensation in the non-cotton Tent?!

[Undersky]

Condensation inside the tent is not too big a problem, but it doesn't help at either.

When it is very cold overnight, say < -30C , inside the 'hot tent' there will always be some frozen condensation evident on the inside of a single-wall tent in the early morning, before the stove is lit. This condensation can be reduced in many ways:
- by good venting the evening before,
- by increasing ventilation overnight,
- by minimizing the area of uncovered snow on the tent floor, near the doorway, behind the stove, etc.
- by having enough heat in the tent for long enough the evening before to dry your gear well,
- by keeping the stove going longer into the sleep time,
- by covering all containers of liquid water,
- by not breathing.

OK, scratch that last alternative 'cause it just creates too many other problems!

Here is my question to those of you who use non-cotton tents, please:

If I am sewing up a solo tent, how important is it to use breathable cotton? Could I be happy with less breathable, un-coated poly or nylon for the walls, and a coated polyester for the ceiling? Should I make the whole tent of light cotton and then have an external fly on waterproof coated synthetic?

I would really appreciate your thoughts.

Thanks!
Undersky

[Bothwell Voyageur]

It’s only really an issue above and behind the sleepers. How about a liner sheet to catch drips and prevent contact with the walls?

[Kinguq]

I use a converted 3 season tent with uncoated nylon canopy and coated nylon fly. In the morning there will be some light frost on the interior, but it sublimates within minutes of starting the stove. I just don't find it to be much of an issue. And I don't think there is any way to avoid it unless you heat the tent all night. You put out a lot of moisture just from breathing, and it is going to condense when it hits that cold nylon, whether or not it is breathable.

Kinguq.

[Bkrgi]

Synthetic single wall tent with wood stove is very manageable. Without a wood stove...no way as your just asking for problems due too moisture. Having the ability to dry everything negates moisture build up overnight when the stove goes cold
I would use a Silpoly if your building a light weight tent...moisture affects it far less than nylon. I used 1.1oz Silpoly PU4000
Clearly breathable cotton wins hands down but that weight penalty is the compromise

[Undersky]

Thank you for your replies! I appreciate your ideas!

Bkrgi, I agree regarding the virtues of Sil- and PU- coated polyester. I have experience with sewing just one solo tent and that material was easy to sew, does not stretch as much, and lightweight for its strength. I think the material I used was 1.6oz. Many, Many times stronger than equivalent weight cotton!

BV, I guess I've never had actual drips of condensation per se, except in a large group tent when a whole bunch of wet/snowy items were hanging to dry over a cranking big woodstove. At that time the drips and runs were on the far end of the tent, and it was snowing. That exterior snow was accumulating and melting a little on the outside effectively waterproofing the tent cotton. Your idea of a liner above the sleepers would certainly work for drips, and for those frost crystals loosened from the ceiling by early morning wind that fall onto the cheeks of still-sleeping innocents!

Kinguq, I agree that the water vapour pumped into the cold air overnight by our overnight breathing is going to sublimate onto all colder surfaces, water-proof or not. Thus, having a breathable ceiling might not make much difference as soon as the tent interior temperature drops below the dew point. I am not into keeping a stove gong all night - especially a little solo-tent stove. Thanks for sharing your experience with your own synthetic tent; it is sharing like this that makes this forum invaluable, I believe.

[Bkrgi]

Thank you for your replies! I appreciate your ideas!

it is sharing like this that makes this forum invaluable, I believe.

Yup is sharing and ideas that set me off on my path to configure my personal set up....thanks to everyone on Wintertrekking
My Silpoly Hammock Hot Tent (12x6') plus large Seekoutside Ti stove weighs in at about 7lbs.... that alone far far out weighs the moisture management issues.
My Atuk cotton tent is really really nice in deep cold camping with a big stove (ordered the Seekoutside big mama(vs the GWM stove I have now for the job) to easily handle that chore while keeping weight down to a min as well as compactness when broken down. With this set up I'm hanging the Hammock out in the open air (no way am I sleeping on the ground) and dry my quilts by day in the tent.

I do love seeing people create and adapt their own setups that suit their needs and share their experience to inspire others to jump in as they see fit for themselves



DSC01108 by richardktm300, on Flickr

[Undersky]

While the lush green grass is a bit incongruous with your hot-tent, the whole thing looks very appealing! If I can figure out how to post pics/vid I will send my most recent sewing job of a little solo tent.

Thanks Bkrgi!

[Bothwell Voyageur]

This one?

[Undersky]

Didn't know you'd caught these shots BV. Thanks for taking them and for posting!
Yes, that is the little solo tent of last winter.
1.6oz sil poly for the roof, and 1.1 oz uncoated ripstop nylon for the 4 walls.
150cm (5 ft.) peak, 165 cm (5.5 ft.) along the ridge, and 225cm (7.5 ft.) from short wall to short wall.
So about 3.9 sq. m., or 41 sq. ft..
Came in at 1.14 kg. or 2.5 lbs.
Short walls are 45 cm (18 inches) tall
I used X-C ski poles, or cut 2 poles.
This was a reasonably successful first shot at a light weight solo tent.
All walls being vertical allow whole floor space to be used to the fullest.
Hope to make some modifications to version 2 this winter: shorten to 210 cm x 150 cm footprint, keep 45 cm short walls and 150cm ridge height, put door on end wall beside stove (rather than opposite stove), add sewn-in carbon fiber corner poles (arrow shafts), improve the peak vent function, lengthen skirt on door, etc.
Maybe even try a separate insulated version!

[Heavy Duty]

Here's a hot tent that I built out of coated polyester 2.2oz. It's waterproof as my early winter/late fall hot tent in the event of torrential rainfall, etc. Perhaps it would have been better deep winter tent if it were made out of non coated poly but the weave is so tight I it my not make a difference. Condensation does build up but it's not an issue the stove melts the frost and dries everything out relatively quick. Don't be afraid to give it a shot, the weight savings are worth it if that's what you're after.

[Undersky]

Thanks Heavy Duty.
I certainly agree that lighter fabric is one quick way to make a lighter tent.
While cotton is very comfortable to live in, it is heavy for its strength when compared to synthetics.
Your sewing appears far more tidy than mine!! Nice job!

[empirecanvas]

Two words: Mechanical Ventilation.

Have some way to dump steamy air, and ensure fresh air during to cold hours. Syntheitc tents can turn into an oven in no time.

[Undersky]

Empire Canvas, I fully agree regarding your statement about steamy air!
By "Mechanical Ventilation" do you mean something beyond wide-open floor-level and peak height vents?
Experience has shown me that the relative "heat" within the tent, even with an ice-cold stove at 4:00am, results in some ventilation still, via simple convection.
Is this what you are referring to when you state "Mechanical Ventilation"?
Thanks!

[empirecanvas]

Roof vents or zippers work great.

[Undersky]

10-4, Empire Canvas.
Thanks.

[empirecanvas]

I once asked Todd Bibler why he left a 3"sq mesh vent atop each tent.

"So nobody dies." he responded.