should I avoid single wall tents?

NM

No.
I think this BPL article ALONE is worth the price of membership:
State of the Market Report: Single Wall Tents (2008)

Dennis:

There are different single wall tents. For example, some use non-breathable fabrics and rely on vents to circulate out warm/moist air produced by your body. Another type use waterproof/breathable fabric.

Non-breathable single wall tents that rely on venting can be a great choice for use in warm to temperate climes at low to moderate humidity. Example: The relatviely dry Sierras in summer to early Fall. These tents do poorly in warm/sultry nights. If the air is still and humid, all then venting in the world won't help. Of course, too much venting can be bad too — so they're not great for winter use.

Breathable single wall tents, on the other hand, work their best in cold but dry climes. They do poorly if the air outside is also humid and the temp is at or near the dew point,

So, the answer is that single-wall tents and tarptents have their place — and they can perform superbly while saving you some carry weight. It mostly depends on when and where you hike.

It is possible to wake up in a tarptent with the walls looking like somebody sprayed a hose inside them. This can freak you out but the condensation does not drip on you. Given that this type of effect is rare, I would say forget about condensation as a factor.

More importantly, I would not use a tarptent in areas above the treeline with high exposed wind. If you are in such areas but can escape to lower levels to camp then this is not an issue. But if you know you will be up high and exposed and can't escape, these are definitely not the tents for you.

Also, forget them when there is a lot of snow.

For the average backpacker these tents are fine.

I know some people that hiked into Mt Olympus this fall with one of the Black Diamond tents made of epic. It leaked and ruined their trip. It was light though! It just sprayed through in the heavy rain.

There are trade-offs, but most ultralight backpacking has trade-offs. Definitely read the article mentioned previously, and definitely follow the link to "condensation tips". Basically, you must have ventilation to avoid condensation. However, even if you button down the tent really tight, you may not have much condensation (depending on how the tent is designed and the conditions). For example, my wife and I switched to a TarpTent Squall 2 (which I recommend very much). She likes to keep things as warm as possible, even if it means a bit of condensation. So, we tend to close off the doors, even when it isn't raining. As a result, we often get a bit of condensation in the morning. This really isn't a big deal, as long as you carry a towel. I carry two really lightweight towels (handy for other things) that weigh less than an ounce. I wipe and wring with the first towel, until I can't do much with the damp towel. Then I wipe with the other towel so it is bone dry. I only do this when putting away the tent (if camped in the same place for a couple nights, it isn't a problem). Of course, I had to do the same sort of thing with the fly on a double walled tent.

Anyway, this is a very long way of saying that you should definitely consider using a single walled tent to save weight. It will work well in most conditions. Except for snow, I would apply much the same rules towards a single walled tent that I would apply towards a down sleeping bag (I would tend to favor a single walled tent a bit more). I wouldn't take a down sleeping bag on a 2 week trip to the Olympic rain forest in November, and I probably wouldn't use a single walled tent either.

Should you avoid single wall tents? No. Here are a few brief thoughts on them:

Single walled TENTS are tents that are made of a single layer of waterproof/breathable material such as Gore-tex, eVENT or a knockoff. For the record, Epic is NOT a waterproof fabric, nor does it claim to be. I have no idea why someone would build a tent with it, yet Black Diamond uses it extensively. A single wall tent can have a lot of advantages over a double wall tent because of simplicity and reduced noise in the wind. Generally, they tend to be pretty muggy on a hot summer night and are best suited for winter use, IMO. Some good single wall tents to look at would be the Bibler I-tent and Rab Summit Extreme (if you can still find one made of eVENT).

Tarptents, not to be confused with single wall tents, are essentially ultralight tarps that have bug netting sewn around their perimeters and waterproof floors sewn to the bug netting. Tarptents can be easier to set up than a tarp depending on how well they are engineered, but generally do still require some fiddling periodically through a rainstorm, as the material commonly used for the tarp portion tends to stretch when wet. Since the tarp portion is generally made of non-breathable waterproof material (as opposed to the breathable/waterproof fabric used in single wall tents), condensation will readily form on the inside of the tent. In theory this is problematic: if your sleeping bag brushes against the inside of the tarp, it could get wet. Ideally, tarptents are built to be roomy and airy enough to minimize the problem. In practice, it works out somewhere in between.

A lot of AT thru hikers like tarptents because they offer the lightweight of a tarp (single wall tents still tend to weigh in the range of light double wall tents), but provides a lot of bug-free space, unlike a tarp.

If anyone is interested, here is what Nextec says about their Epic fabric:

"EPIC by Nextec® fabrics are highly water resistant. This means they resist penetration by water under all but the most extreme conditions."

"resists penetration"
"extreme conditions"

Well ok, but what are the figures for Hydrostatic head like?

My experience with Epic (as tested with a Black Diamond Firstlight tent):

BD claims 5 hours of rain resistance before rain penetration. My own experience is actually even better — 9 hours. I would feel comfortable with Epic where rain is either seasonal (easily predictable) and/or relatively fleeting. If there's any chance of hard, day-long or multi-day long rain, I would NOT use Epic.

9 hours may seem like a long time, but picture this scenario: It's been raining all day, it's now 3pm, and the gang wants to stop for the day. Now, do you join in and set up your tent — and hope that the rain will stop before midnight? Or do you just sit in the rain until 9pm — then set up your Epic fabric tent — so it will remain dry through the night and into early morning?

For me, they are a great choice for most applications. I'd use them for most three-season backpacking in the U.S., except for consistently wet or windy spots.

I used a Lunar Solo on the CDT last summer and loved it. On my Alaska Traverse I used a tarptent. Both were great compromises for weight/performance.

Most of the time there is little or no no condensation, most of the rest of the time there wasn't much, but even at it's worst I could deal with it.

Heat wasn't a factor for me because I'd only be in my shelter in pouring rain or when the sun was down or very low. No doubt at noon in a sunny spot in a hot climate they could get very hot indeed.

As noted, check out the outstanding report on single wall tents here on the site, one of the best articles on the subject anywhere.

nm

Let's assume (real world) that you are in humid winter conditions and inside tent does get a lot of condensation while sleeping, how do you keep condensation from falling on your down bag when wind blows?

Won't wind knock condensation off inside tent onto your nice dry bag and possible get insulation wet over several hours?

If you use bag cover won't you potentially increase your sweating which would increase condensation. Is this where a VBR would help instead of bag cover? Or is spray light enough not to be a problem?

Chuck

> how do you keep condensation from falling on your down bag when wind blows?

The answer is not what you might have expected: you make sure your tent has a reasonable amount of ventilation.
To explain: when there is a reasonable amount of wind going through your tent it is uncommon for condensation to form on the inside. Condensation is far more likely when the air is still.

Condensation may well form when the air is still and it is raining. Then the raindrops can bounce condensation off the inside of the roof. Some will tell you that the tent is leaking, but that is *extremely* unlikely unless you have an utterly crap tent.

Of course, if it is -10 C then you may get 'condensation', but it will be frozen solid!

Cheers

> Won't wind knock condensation off inside tent onto your nice dry bag and possible get insulation wet over several hours?

Wipe down the inside of the tent with a towel before bed. Some folks wake up in the middle of the night and give it a bit of a wipe too if there is a lot of condensation about. In a well designed tent the condensation should only get knocked off by either rain outside or really strong winds.

> Wipe down the inside of the tent with a towel before bed.
I use a little pink kitchen sponge – even lighter than a towel. But anything will do.

Cheers

Posted by HikeLite: "Let's assume (real world) that you are in humid winter conditions and inside tent does get a lot of condensation while sleeping, how do you keep condensation from falling on your down bag when wind blows?"

I gave up on single wall (tarptent type) in MD / N.VA in the spring / fall due to high humidity and lack of wind. Any rain or bumping the tent while sleeping caused lots of big condensation drops to fall. My 3-D synthetic sleeping bag (standard "low tech" nylon outer) didn't wet out enough to make me feel chilled, but it definitely felt damp (and didn't dry even when hung all day in base camp).

Summer was fine (high temps). Winter was OK (10% less humid and 5 mph more wind). Fall / Spring rainstorms were also OK (only 5% more humid, but a lot more wind).

The breezyness of the tarptent design made the hot super-humid summer nights MUCH more bearable. The breeze was too cold in the winter though, and I didn't like the confined space & high condensation of a bivy (in MD / N.VA's "damp" winters).

My advise is to take your double wall on a few more hikes, and pay close attention to how much condensation is on the underside of the outer tent – and how much wind is available to prevent that condensation in a tarptent.