Is it my tent or is this normal???

[kmac]

Last night I decided to tent out in the backyard. I slept great but when I woke up the inside of my tent was all wet as well as the top of my sleeping bag. The temperature last night was in the low 30's. My tent is a Big Agnes SL1. It's a double walled tent and perfect for one person....but why is it so damp? I've never had this problem when I stay out in my two person tent.

-MEB

meb
what makes a tent a 3 season verses a 4 season?
kmac

 

[ghassert]

I have the same tent and experienced a similar problem a couple of weeks ago. The first two nights it was prety warm out and I had no problems. The 3rd night out it went down to the low 30's and in the morning the top of my bag and the inside of the fly were wet, the outside of the tent was also covered with frost. When I went to bed the next night I opened the vestibule about halfway and it was pretty dry the next morning except for very light condensation the next morning. I'm also a very warm sleeper and don't usually don't zip the bag up fully, I don't know if this makes a difference or not.

 

[DougPaul]

what makes a tent a 3 season verses a 4 season?

A true 4 season tent will be sturdier and may include such features as snow valences (flaps around the bottom of the floor which can be buried in the snow to keep the wind from blowing underneath). Also typically has a vestibule that is big enough to cook in, if need be. Think of something that you would like to have if camping above timberline in the Prezzies...

The NF VE-25 has been a classic 4-season tent. The NF Mtn-25 looks like a decent example: http://www.rei.com/product/47693191.htm.

3-season tents are generally adequate below timberline in the NE.

The line between 3-season and 4-season is blurry and it may "be" whatever the manufacturer claims it to be...

Go to http://www.rei.com/rei/shoplettes/t...nts_shoplette&vcat=REI_SSHP_CAMPING_TOC#tents and follow the links for more examples.

Doug

 

[kmac]

A true 4 season tent will be sturdier and may include such features as snow valences (flaps around the bottom of the floor which can be buried in the snow to keep the wind from blowing underneath). Also typically has a vestibule that is big enough to cook in, if need be. Think of something that you would like to have if camping above timberline in the Prezzies...

The NF VE-25 has been a classic 4-season tent. The NF Mtn-25 looks like a decent example: http://www.rei.com/product/47693191.htm.

3-season tents are generally adequate below timberline in the NE.

The line between 3-season and 4-season is blurry and it may "be" whatever the manufacturer claims it to be...

Go to http://www.rei.com/rei/shoplettes/t...nts_shoplette&vcat=REI_SSHP_CAMPING_TOC#tents and follow the links for more examples.

Doug

Thanks
kmac

 

[sugahjohn]

On a related note: A couple of weeks ago, I noticed the start of some condesation inside of my tent (REI Halfdome) about an hour or so after I had set it up, and neither I nor the dog had been in it! Does anyone have any idea why this might've happened? To provide some background info:

1.) the tent was packed in its stuffsack in the cab of my truck all day
2.) it was a relatively cool day, and the cab of my truck was parked in the shade (so the cab wasn't really warmed by the sun)
3.) I don't think there was a dramatic temp change from the time I removed the tent from the truck to when I set it up. (Obviously, there must've been some temperature change.)
4.) I set the tent up at dusk, in shaded spot--I can't say, however, that the spot was in the shade all day long.

Could the difference in ground temp vs. ambient air temp have caused the condensation inside my tent? (When I was setting up the tent, I didn't notice any condensation or dew on the ground.) As Pete Hickey noted, upon awakening, there was frost on the grass and, indeed, that damned grass wasn't inside my tent, to the best of my recollection.

Thanks!
John

 

[DougPaul]

Could the difference in ground temp vs. ambient air temp have caused the condensation inside my tent? (When I was setting up the tent, I didn't notice any condensation or dew on the ground.) As Pete Hickey noted, upon awakening, there was frost on the grass and, indeed, that damned grass wasn't inside my tent, to the best of my recollection.

The thermal capacity of the tent fabric is negligible, so the initial temp of the tent has little effect--just a tiny amount of condensation will warm the tent fabric to ambient. (I presume the tent was dry initially.)

If the sky is clear and you have a skyview from the tentsite, you can get radiational cooling of the tent. It is possible that moisture from a warm damp ground (or just a general high humidity) can condense on a radiation-cooled tent. If this is the case, I'd generally expect moisture on the top of the tent too--although it is possible that moisture from the warm damp ground could be trapped under the fly and have no where to condense except under the fly and on/in the tent body.

Doug

 

[sugahjohn]

Thanks DougPaul! There was condensation in- and outside the tent.

 

[Stan]

Sleeping out about once a week or so... works out to approx 30 nights a year for me

Would work for me too as that's about the amount of time I'd otherwise spend in the dog house.

 

[mtnpa]

I think Pete Hickey may be right about the grass being a factor...

 

[dug]

That amount of condensation in a double-walled tent is not normal (normal being my experience with a number of tents in various temps and numbers of people over the years). The condensation and snow-flaking occurs on the fly, not inside the tent. That's a major feature/benefit of a double-walled tent.

Careful with this, though. A good single-walled tent I've found breaths better than a double-walled. I've never had any issues with my Bibler. I ended up selling a TNF EXp 24 because of the poor ventilation. Strictly winter, mind you. But, it's a myth that single-walls don't breath, and quite well.

 

[Woody]

My wife and my daughter already think that I'm crazy. I'll have to try camping in the back yard and see what they think of me then! Seems to be a reasonable way to test your gear and systems. Fortunately my yard is private enough that the neighbors won't see me.

 

[Pete_Hickey]

.... I'll have to try camping in the back yard ....... Fortunately my yard is private enough that the neighbors won't see me.

I'm out camping in the yard every time I have a fight with my wife. Neighbors see me, and they've figured out why. The only problem in the yard, is getting up to pee at night.

 

[sugahjohn]

The only problem in the yard, is getting up to pee at night.

Bring a pee bottle--just make sure it's a different shape from the one you drink from! You can always empty it in the neighbors yard before they awaken!

 

[MichaelJ]

The only problem in the yard, is getting up to pee at night.

Remember back on page 1 when Pete talked about the grass being covered in dew?

*cough*

In any case, condensation is always going to be an issue. A double-walled tent has the concept of letting the air come in under the edges of the fly and dry out any that forms (or even keep airflow going so it doesn't form) on the inside of the fly.

In the winter, that makes for *cold* sleeping conditions if the wind is blowing on you, which is where the "4-season" term comes in, with a tent design that limits the amount of ventilation inside (as well as usually being thicker material, more wind-resistant, able to support a snow load on top). The result, though, is going to mean more chance of condensation.

Best thing you can do is to leave as many little vents open that you can. My Bibler has two small ones right up on the top, and a protected area at the top of the door, the idea being that it will actually "chimney" and draw air through. It works, depending on the wind direction. Try to do something similar. In fact, use any wind to your advantage. Get a draft of air going that's enough to keep the air in the tent dry while not freezing you out of the 10 meager degrees the tent is giving you.

And if you set up on snow, don't bury the fly or tent edges entirely in a snowbank. Leave gaps, again to provide an air draft. It not only keeps you dry, it keeps you from suffocating.

 

[Chip]

When it gets below 40 or we'll be more than 2, I use a Sierra Designs Alpha CD. This is a 3 to 4 season convertible (by zipping closed the vents and using the complete 3 pole system). I have an electronic thermometer with a lead wire you can string outside to record high/low inside/outside temps (gear head alert ). In it's fully zipped up winter configuration I've recorded low temps 10 degrees lower outside than inside the tent.

Last Jan Daxs, Jay H and I slept in the tent in what started as rain then turned to freezing rain and eventually snow as temps dropped from around 45 to 10. The fly was a nasty frozen mess in the morning, but I don't recall any condensation inside.

I consider the warmer temp in the tent a great advantage, especially when the 4 boys I take are in it in colder than comfortable temps. If I had to open everything to vent it, that would obviously be gone.

Read the disclaimer. This has been my experience.

 

[DougPaul]

Ventilation (colder, but dryer) vs condensation/frost is a trade-off. I generally choose to stay as dry as is practical.

Doug

 

[UNFROZENCAVEMAN]

So what everyone is saying is:

Negating the thermal capacity of the tent fabric, even if you do give some consideration to the ground temp. vs. ambient air temp and moisture content of said tent site, Pearson Correlation Coefficient (which measures the strength of the linear relationship between two variables) would indicate that there is a "1.0" or a perfect positive correlation between the volume of air, how hot the person in said tent is , and the resulting moisture buildup. This of course assumes that both variables (often called X and Y) are interval/ratio and approximately normally distributed, and their joint distribution is bivariate normal.

I think that dr wu002 was on the right track here when he suggested a full astronaut suit however, I'm surprised there wasn't any mention of a SCITTBA* although I know the tanks get a bit heavy when doing longer hikes, they are quite effective.


*Self Contained In The Tent Breathing Apparatus

 

[DougPaul]

I'm surprised there wasn't any mention of a SCITTBA* although I know the tanks get a bit heavy when doing longer hikes, they are quite effective.

Perhaps you can get BD to offer a version of the AvaLung (http://www.blackdiamondequipment.com/gear/avalung_ii.php) with a longer set of tubes. No heavy tanks to carry around...

And don't forget to wear a VBL whenever you are in the tent.

Errr... Better bring a stove hood too, in case you have to cook in your tent.

Doug