Zpacks Duplex

The Zpacks Duplex [] is a two-person tent, purpose built for ultralight backpacking. It's really expensive at around $600, but the price shouldn't be the

6 years ago

Latest Post Immortality by Matthew Sluiter public

The Zpacks Duplex is a two-person tent, purpose built for ultralight backpacking. It's really expensive at around $600, but the price shouldn't be the end of the story — it's also super light and very spacious. Other tents in its class come in at around three pounds, whereas the Duplex is roughly half that.

Since the shelter is one of the Big Three , choosing the right one can be a little stressful, considering how much a high quality, high performance shelter can cost. It's something you'll have to carry all day and it's going to be "home" for months, so you'll want something lightweight but also with lots of room. Before my thru-hike, I bought and tested a handful of tents and tarp-plus-mesh combinations before finally settling on the Duplex. Honestly, it was the price, the non-traditional setup, and my unfamiliarity with the fabric that initially turned me off to the Duplex. Being dissatisfied with the weight and complexity of these other shelters, I'm glad I took a chance on the Duplex. When all was said and done, the Duplex performed admirably on my thru-hike of the Pacific Crest Trail.

The Duplex has a lot going for it, so let's get into it, shall we?


The Duplex is made of a cuben fiber top, NoSeeUm mesh walls, cuben fiber doors, and a cuben fiber bathtub floor. It's an all-in-one design, meaning the tent body and fly are not separate things. The tent is not free-standing, but a set of carbon fiber poles can be purchased separately from Zpacks to make it so. I've seen people try to use them and, in my opinion, they are kind of awkward and seem like a bit of an afterthought. The tent is intended to be setup with a minimum of two trekking poles and six stakes. The trekking poles can be replaced with two aluminum or carbon fiber rods, or even two straight branches, in a pinch. In windy or snowy conditions, the two main wall panels can also be staked out, providing a more rigid structure overall.

All-in-one design, set up with only two trekking poles and six stakes.

The cuben fiber door flaps can be rolled up in fair weather and pulled close in bad weather, all without extra stakes or poles. The newer models include a toggle-and-loop closure in the middle of the door flap, which keeps the door fabric from fluttering wildly in extremely windy conditions.

Toggle and loop closure in the middle of each door flap.

The side walls are made of a very thin NoSeeUm mesh. Each side wall has its own rainbow-zip door, so being a two-person tent, each person can enter from their own side. Used as a one person tent, entry on both sides allows for pitching in some tight spaces while still having at least one convenient way of entering the tent. Two doors is good. The zippers on on the entries are difficult to use one-handed and tend to bind a little at the start. They do not catch on the mesh though, so that's a plus.

The bathtub floor is attached to the tent with the NoSeeUm mesh walls along the length of the tent, and a small mesh vent panel along the width. This provides a completely enclosed, bug-proof space inside the tent. The floor is cuben fiber too, providing a completely waterproof bottom for the tent. This means that if you have to park in a depression or slope that might collect water in a storm, you may still get the water bed effect, but at least you'll be dry. The floor is held up at both ends of the tent by hooked lines, allowing you to raise or lower the floor to adjust the amount of ventilation.

All of the exposed seams on the outside of the tent are taped, or sewn and taped. Any tent worth your money will have this feature. Taped seams should become an industry standard and par for the course in tent design, but alas, that's not the case. Taped seams means that there are no exposed threaded seams in the outer shell or bathtub floor that can absorb water and possibly move moisture from outside the tent into the living space. Zpacks understands this and tapes the seams as standard practice.

Zpacks uses bright, yellow-green Dyneema® cord for all of the guy lines. The line is tough, but a little stiff. While super bright, the line is not reflective, so be careful walking around the tent in the dark.


The stuff sack that Zpacks includes is big enough to hold the Duplex, a ground sheet, and eight MSR Groundhog stakes. After more than 150 nights on trail, it started to shred into very fine threads and several holes appeared. The stuff sack is made of very thin cuben fiber and doesn't seem to hold up very well over time. I will either replace it with a stuff sack from Hyperlite Mountain Gear, or just ditch it altogether. We'll see.

The stuff sack developed holes, but it also traveled over 2000 miles. Not bad.


The majority of the tent is constructed of cuben fiber, which is an ultra lightweight, completely waterproof material that is also very abrasion resistent for its weight. Using the tent on bare Sierra granite didn't wear through the material either. It's pretty tough stuff.

Its better than average in-plane tensile strength means it doesn't stretch or sag as much as other tent fabrics, partly because it doesn't absorb water.

Its out-of-plane tensile strength, or how much it resists thorns, sticks, and rocks poking holes through it, is pretty average. If you expect to be in "poky" conditions, use a ground sheet to protect the bathtub floor. Having used the tent for about 150 nights on the Pacific Crest Trail, I only poked a hole in the floor once. It was a very sharp, very thin thorn, so in fairness, it would have gone through any type of tent material. I patched both sides of the hole with some cuben tape and it's as good as new.

A little bit of cuben tape to patch a hole smaller than the diameter of a paper clip. Can you spot the tape?

About a thousand miles after patching the first hole in the floor, I added a silnylon ground sheet to my kit. Why silnylon? Because it was the only thing available to me at the time. Now that I'm home, I have a little more choice and I intend to pick up a sheet of polycryo to use as a groundsheet instead.


Zpacks offers the top shell in two different thicknesses, 0.51oz and 0.74oz per square yard. The thinner material produces a 21oz tent, while the thicker material produces a 23oz tent. The thinner material is much more transparent, in my opinion, especially in bright light. You can see only a fuzzy image of what's inside, but if you are concerned about privacy, you don't pay a huge weight penalty by going with the thicker material. I went with the thicker 0.74oz material, but if I could do this all over again, I'd go for the 0.51oz material. I guess I'm not that modest after all.

0.74oz material is a little less transparent.

The NoSeeUm mesh is pretty standard stuff and used by just about every other tent manufacturer. Nothing special there. The sewn seams that join the cuben fiber to the mesh seem to be the weakest spots in the tent. Using the tent for about 150 nights this past summer, I noticed considerable wear just beneath the zipper stops and in the four corners of the tent. I reinforced those areas with some cuben and Tenacious tape, and it's almost good as new. Almost.

A little bit of Tenacious tape where the mesh, cuben, and zipper meet.


Setting up the tent is pretty easy. Stake out the four corners first, then insert one pole and stake it out, then do the other pole and stake it out. Last, do a walk around the tent, using the included line locks on each guy line, give each line a little tug until it's tight. Done.

I use MSR Groundhog stakes, but I've seen others use a standard shepherd hook design with great success too. Zpacks doesn't include stakes in the purchase price, so you'll need to provide your own. For the price of the tent, it would be nice if they provided stakes — but given the wide variety of personal preferences and opinions in ultralight backpacking, I understand why they don't step onto that minefield.

In bad weather, I stake out the two guylines attached to the middle of each main wall panel. It stops the main wall panel from collapsing under heavy snow or billowing in high wind, and it also provides a smidge more livable space at each end of the tent.

Main panels staked out. Door flaps closed.

Having set up the Duplex in all types of weather, including wind, rain, and snow, I appreciate the all-in-one design. Since the Duplex has the rain fly built-in, I never worried much about having a wet interior while setting up in the rain. Some double wall tents can be setup skin-out (fly first) with the tent body second, but doing it all in one shot is pretty convenient.

Because the tent is not freestanding, it can be tricky to stake out on rocky ground. Site selection becomes a little more crucial for a good pitch. After a while, you get creative and just find ways of making it work, either by stacking rocks or guying out to bushes or trees. For some, this may be a deal breaker. For me, it wasn't as big of a problem as I thought it might be.

Stacking rocks ain't easy, but sometimes it's necessary. Hey, it works.


In high wind conditions, orienting the Duplex can be critical. If possible, I always turn the tent corners or doors into the wind in an attempt to avoid a situation where the wind would hit the main wall panels head-on. On my thru-hike of the PCT, I only had the tent collapse once due to winds. In retrospect, I was still a noob on the trail: it was a lazy, limp pitch, it was staked out in very loose sand, and the straight winds coming down into the valley were hitting the main panel directly, causing it to billow inward like a sail. I watched two Fly Creek tents go for a roll before my Duplex finally let loose and collapsed on me. That night was classic Type II Fun. It can be said that in windy conditions, site selection is critical for any tent — maybe a little bit more for the Duplex.


Rain and humidity pose a different set of problems for the Duplex. Cuben fiber is waterproof — in both directions. That is, it keeps water out, sure, but it also keeps it in. In some situations, this can create a buildup of condensation on the inside of the tent. Condensation is a problem for just about all tents, but the Duplex seems to corner the market on this particular issue. Even though the two side walls are constructed completely of mesh, there is very little ventilation with the cuben fiber doors in Storm Mode™. If there is a slight drizzle, leaving one of the four door flaps rolled up alleviates most of the condensation buildup. In heavy rain, you just have to close the doors and roll the dice. Again, for some this may be a deal breaker. I've read quite a few reviews that knock the Duplex for poor ventilation. I can remember only a handful of nights where condensation buildup was a problem.

Wet outside. Dry inside.

In heavy rain, the fat rain drops can sometimes create a misting, or splash back, effect — the water hits the ground and splashes under the ends or doors of the tent and through the mesh panels. Lowering the pitch can help some, but the two main wall panels should probably extend another three or four inches over the bathtub floor to alleviate this problem. It's something I'm going to ask Zpacks about, but since I'm a nobody to them, I don't expect a response.


As a single-wall, non-freestanding tent, the Duplex is decidely not a four season tent. Since cuben fiber is pretty slippery stuff, it handles a light dusting of snow quite well. In a heavy, wintry mix of snow, sleet, and rain, you really need to keep an eye on it. Cuben fiber is slippery, but water and sleet will still freeze to it, which will in turn create a sticky place for snow to buildup. Snow buildup on the outer shell of the tent will stress the guy lines and may actually pull the stakes out of the ground, causing the tent to partially collapse, or collapse altogether. I have first hand experience here. Its something to be aware of. With that caveat, the Duplex didn't wet out, tear, or otherwise fail in these terrible conditions. It was survivable.

Heavy snow or freezing rain can weigh down the tent and, potentially, pull the stakes out.

Drying Out

Drying out the tent is pretty simple. Since the cuben fiber fabric absorbs absolutely no water at all, water evaporates off the surface pretty quickly in a slight breeze or in a modicum of sunlight. If the outer face of the material is relatively clean, a quick shake will remove the majority of the water. If the material is dusty or dirty, it may need a little more dry time, since dust and dirt absorb water.

Drying out after rain.

Thawing out after snow.


As far as comfort and livability goes, the Duplex is outstanding. For a two person tent, it's probably a little tight for two people plus gear. For a single person plus gear, the tent is a palace. I'm 6' 3" and I can sit straight up in the middle of the tent without hitting my head. There is plenty of space for cooking and fiddling around inside the tent. Laying down, there is plenty of space around my head and feet. I move around quite a bit when I sleep, so having a little extra space inside the tent helps.

I've heard some people complain about the tent being noisy — "crinkly" was the word, I think. Cuben fiber can be a little noisy, especially when it's new. Over time, rolling and unrolling the tent will naturally loosen the fibers a bit and the tent gets quieter as a result. There have also been complaints of rain-on-cuben sounding like being in a popcorn maker. I don't know if I'd describe that way, but it's definitely not silent. In my opnion, I don't think its much louder than rain on a silnylon tent. Regardless, I never considered noise to be a problem.


Now we come to the real issue facing most people who want to buy, or are considering buying, a tent made with cuben fiber: it is very expensive at $600 — especially compared to identically designed silnylon tents. Silnylon can cost a half to a third as much. Cuben fiber does have it's advantages over silnylon: in particular, its strength, abrasion and water resistence, and weight. However, the performance of silnylon in each of these categories is adequate enough for most people, making the high cost of cuben fiber completely unjustified. For me, the extra cost of cuben fiber is defensible in some cases, thru-hiking being one of them, where every ounce counts just a little bit more.


So, here I am, nearly 3000 words into the review and I can't think of a good ending. I was trying to think of a way to sum up this review with a bang, or at least with a hearty Buy! recommendation, but I just can't do it. I guess I don't regret buying the Duplex?

Gosh! That's not a ringing endorsement!

Maybe I can end by asking myself a question. If I had $600 burning a hole in my pocket, would I buy the Duplex again? Yes. Well, maybe. Since purchasing the Duplex, two things have happened: I've walked the Pacific Crest Trail and I've seen other compelling tents in action, including other Zpacks models. I'm tempted by the Altaplex, Solplex, and even the Hexamid. Silnylon designs from Tarptent, MLD, and Gossamer Gear are also intriguing.

OK, that's not a good ending either. Let's try an anecdote. My friend Peanut started out using a traditional style Big Agnes Copper Spur on the PCT, but I think the extra weight, bulk, and things to manage was getting to her. She was eyeing my Duplex for a few hundred miles, and after hemming and hawing a bit over the price, she finally bit the bullet and bought one. She loved it, even though it's not perfect. I think she's going to put up a Duplex review of her own on her blog.

That ending doesn't work either. OK. Let's just state some facts then. Right now, I have the Duplex and I intend to use it until it's not worth repairing anymore. Tents from other brands are simply not game-changing enough to get me to replace my Duplex. It performs well enough in each of the categories that count. Even though it's a large, two-person tent, it's as light as — or lighter than — other high-end, traditional single-person tents. It's not cheap, but in the conditions I encountered on my thru-hike, it outperformed silnylon tents, hands down — and that's worth money to me.

Yeah, it's not a cheerleading end to this review and it's not a very definitive answer to "Should I buy this tent?", but the Duplex is a very good tent, and should definitely be on the short list of tents to consider.

There's no mic drop here, folks. The review is over.

Why are you still here?

Matthew Sluiter

Published 6 years ago