Tent as a Bivy?

[PackHorse]

Has anyone used their tent as a Bivy or extra layer in a shelter during extreme cold weather? Not deployed of course, just for another layer of protection. Is there a potential benefit, or would it contain moisture?
Linda

[MuddyWaters]

one person in a typical 2 person 3-season tent will add maybe 3-5 degrees or so. I verified it on my 3 season tents with remote thermometer when car camping with scouts. Dont remember the actual amount. It was still, not windy. That would make a big difference.

2 persons in a tent, adds a lot. My son and me added about 8 F in my tent when he was 11.

But people freeze in shelters all the time, when they would be warmer IN THEIR TENTS

Or, maybe they just like spooning with strangers.

[Slo-go'en]

Since tents are made of water proof fabric, yes it would trap too much moisture and you'd wake up soaking wet. You'd be better setting it up (outside the shelter) and use it as it is meant to be used. Then it will add a few degrees and eliminate any wind chill.

[Just Bill]

Has anyone used their tent as a Bivy or extra layer in a shelter during extreme cold weather? Not deployed of course, just for another layer of protection. Is there a potential benefit, or would it contain moisture?
Linda

Yes... depends where your problem is.


Unless the shelter is a really good one... most of the time you will be warmer outside it on the ground. Most shelters have a raised platform so the floor is colder than the ground. If it's pouring rain though likely you'd do better staying dry inside.
Fly- wrap it around your body before you get into your insulation (over your base layer, but under any other layers, it will serve as a VBL and add a few degrees of warmth.

If the howling wind is the problem- use the fly to block a shelter entrance or better use it to make a small lean-to shelter and sleep on the ground.
You can use the tent body to make a bivy- orient the floor side under your pad and with a foot or two on the wind side. Make sure you have the mesh openings of the body near your face.

If your pad is a bust... you can fill the tent body with any leaves or other debris you can find and use it to make a pad. If you have no debris but you do have a pad, roll the body up into a rope type shape, then close it into the biggest loop or rectangular shape you can and set your pad over it. (trapping an extra layer of air at your torso)

If the insulation in your bag is a problem but your pad is good- roll the body up again into a rope. Sleeping on your back, put the tent body in an upside down u shape across your chest and down your thighs. This will add to the trapped air layer in your bag.

If you are generally prepared and happen to encounter a helacious one of a kind night... don't worry about trapping moisture. Get through the today before worrying too much about tomorrow. Bail if needed.

Finally- Not sure why more people don't mention it... but the simplest solution of all is to get up and hike. Your body is at it's coldest and weakest lying in bed at rest. Even if you don't want to hike (or weather conditions prohibit it)... stuff the tent body and any insulation you can find into your clothes, drape the fly over your head as a poncho and jog in place if you need to.

For less extreme situations like just being 10-15 degrees cooler than planned. You will feel more rested, and have more energy if you simply walk through the night and fall asleep in the daytime. You burn alot of calories shivering all night, and it may take you a full zero laying around camp to recover. Most areas we hike drop 20-40* from night to day, if it's unexpectedly too cold to sleep, then don't. Pull an all nighter and sleep in the morning when it has warmed up enough that you will actually get some solid rest and recover.

Sides that... no better stars and views than on a cold crisp night. ;)

[Just Bill]

Forgot the better trick...
Fold your pad in half and sleep in a fetal position.
If you have a quilt this will also let you fold the top half inside and nearly double it's warmth.

Sleeping fetal can add 10 degrees alone, doubling your pad and quilt insulation is another huge boost.
If that don't do the job then you just plain done fugged up. :D

[Dogwood]

Has anyone used their tent as a Bivy or extra layer in a shelter during extreme cold weather? Not deployed of course, just for another layer of protection. Is there a potential benefit, or would it contain moisture?
Linda

I've used a silny, CF , or spinnaker tarp as loosely draped top layer in extreme cold weather. Umm, for protection. Umm, to trap some loss of warmth from conventional heat loss as an impromptu so so solution. I'm not in the habit of doing it as there can be undesirable consequences over several days though.

As your body emits heat and as it rises as you sleep yes it can easily contribute to moisture/condensation/vapor issues.