MYOG: tyvek ground cover / bivy combo

John,
IMO use the spray adhesive and wash the completed bivy to soften and quiet the material. The material will add warmth to your selected sleep system, venting requirements if needed are user specific.

Post a picture of your completed project.

Thanks, Thom. I’m hoping my Tyvek bivy will be able to handle a little rain, but I don’t expect it to be fully storm-proof. Have you ever tried making a bivy with a DriDucks top? It’s waterproof-breathable and pretty light, so I’d think it would work well on the top with another more durable material on the bottom (maybe Tyvek!).

Also, I read here on BPL that the TT Sublite is made out of 1443R Tyvek (aka Soft Tyvek) and it seems to be fairly waterproof. Can I conclude that Tyvek homewrap (Hard Tyvek) is more waterproof than Soft Tyvek?

Not sure if this link has been shared before or not, but I’ve found it useful: MaterialConcepts

EDIT: I was unable to find Tyvek anywhere in my city in a size smaller than a 150 foot roll, so I’m going to try making a DriDucks bivy instead.

Hi guys

Here is a photo of a bivy I made using Home Wrap Tyvek, based on Thom's design, with the addition of a side zip.

Dimensions are:
– Length (excluding hood section): 195cm (77")
– Width at top: 82cm (32")
– Width at bottom: 63cm (25")

I field-tested in last week over a couple of nights, with the temp dropping to 2-3 degrees C. (35-37 degrees F). I used it under a MYOG tarp-tent (Henry Squires style).

It was a bit snug-fitting. I had a thick (cheap, synthetic) sleeping bag and a 3cm (1.2") pad inside the bivy, plus thermals and fleece jacket. Quite a challenge to roll over, which I do a lot. I started with the sleeping bag draped over me, quilt style, but I got too cold underneath and ended up with the bag zipped up.

It was great at blocking a cold breeze that was blowing. Although the hood flap would do better with some means of closing it up – a tie loop or perhaps just some velcro to fasten it to the main bag.

I had a major issue with condensation on the second night, with the sleeping bag getting quite damp – and cold! It wasn't too bad the first night, so perhaps it had something to do the with the mist/drizzle being blown through the tarp and the fact that the bag was fairly open at the top.

Given the issues with fit and condensation I am considering making another, larger one, using 1443r Tyvek and based on the Mateusz version elsewhere here (http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=17099&skip_to_post=129567#129567)

I use Tyvek HomeWrap for the floor of my Uber Bivy.
It is remarkably durable for the weight, However it is NOT very breathable.
You need a waterproof/breathable top.

Hi David

What material did you use for 'das Uber bivy'?

…and any chance of a pic?

Andrew

Andrew,

Just google Uber Bivy for pictures.

I used a microporous polypro, very breathable.

Dave

I never got around to making a dri-ducks bivy as I posted about above, but I finally bought some Tyvek off e-bay and made myself a Tyvek tent. My goal in building this tent was to provide a shelter for me, my 50-lb dog, and my gear in a light rain. I think if I pitch my GoLite poncho tarp over my Tyvek tent, it could withstand some pretty heavy rain.

The whole tent was made from a single piece of Tyvek Housewrap from a 9' wide roll. I cut out the shape shown below:

And then folded it into the tent's shape. This way, the tent only has 4 seams: two on the bottom and then two for the door to open. The ones on the bottom were glued using Super 77 and then taped over. The front door is simply secured via velcro tape. This allows me to vent the door as needed. Living in Arizona, I'm not too worried about condensation.

The tent measures 44'' wide x 78'' long x 36'' tall. The width is just fine, but I'm 5'6'' and wish I had made it a little longer because it's kind of tight in the foot area. It's not too bad, just something I would change if I build it again.

The tent is supported in the middle by a trekking pole, and then I made four loops out of Tyvek on the tent's corners so it could be staked out. This provides a surprisingly secure pitch, even with the door open. Here are some pictures of the completed tent:

The only thing it's missing is one strip of velcro tape to secure the bottom of the door (I ran out and need to get some more), but so far it weighs 16.3 oz! This weight is the tent only and doesn't include the stakes or trekking pole. I've spent one night in my backyard in it so far and have found it's not too loud to sleep in and that venting the door is pretty key to staying comfortable on hot summer nights. I think I may have finally found a durable, dog-friendly ultralight tent.

wow. There's food for thought. Simple, cheap, light, and it works (at least in Arizona and probably in the Mojave where I spend my time).

Let us know how it works for you the first time it rains (or maybe you could pitch it in your back yard and hose it down?)

I'm dying to know — thanks a million for sharing!

Since I'm not expecting rain for a very long time, I hosed it down for about 5 minutes before sleeping in it. I tried pointing the hose directly at nearly all points of the tent as well as letting it "rain" down on the tent. The only water that got in was through the bottom flap (which I hadn't secured with velcro yet). The rest of the inside was completely dry and the inner walls didn't feel damp at all. I'd expect very little (if any) water to get in after I completely velcro the door. Anyway, the tent stood in very wet grass/mud all night and the inside floor stayed dry the whole time.

I think the main point of possible entrance for water will be the door. This could probably be considerably reduced by a adding a storm flap, but that would add weight and I don't think it's really necessary. If I'm expecting it to rain a lot, I'll just bring my poncho tarp and pitch it over the tent, maybe even make a vestibule out of it.

Another thing I might change if I build a second one would be to use a stick-on zipper instead of velcro tape. The velcro tape works and is really simple, but it's really loud when opening the door. If any one is interested, I can post dimensions for my tent as well as for one that would utilize the full width of a 9' and 10' Tyvek roll.

The tent was pretty heavily influenced by the TarpTent Sublite. I would have bought a Sublite, but I wanted something big enough for me, my dog, and my gear. I normally don't hike with trekking poles, so I also wanted a 1 pole design. And since I haven't learned to sew, Tyvek seemed like an ideal material.

Very nice, John. Now if we can just find 9' wide cuben …

Can be done, I bought a piece of 9' tyvek for my hex 3 tray groundsheet.

Nice geometry exercise! I would consider cowled vents, like the ones used on the GoLite Shangri-La 1 and 2 models. It's going to get soupy in there, and maybe not even enough air for you to breathe safely.

Someone should try the soft stuff for a cape shelter configuration.

Thanks, Walter. You could make it using 8 yards of 54'' wide cuben fiber from zpacks bonded together. Hmm…

Dale, I have thought about adding in some top vents for when I can't let the door vent. Shouldn't be too hard.

just thought i'd share my experience making a tyvek bivy. i used velcro for sidetop openings. i found i tend to want to "rip" the velcro open, and it sometimes tears the tyvek. the material tends to want to peel off in layers. a zipper probably would have worked better.

I've just "puddle-tested" a tyvek postal envelope of the hard structure type, which I had already transformed into a square bottomed stuff sack and thoroughly hand fumbled and creased while and after doing so (now it ain't so hard structured anymore).

I lined a measuring cup with the stuff sack's side wall, and filled the tyvek puddle with about 250cl of tap water, taking care not to submerge any seams. The tyvek didn't touch the bottom but it did touch to the cup's wall due to the water pressure. Water started slowly dripping through bottom part of the puddle and it also wetted out where it touched the measuring cup wall.

Has anyone tested a piece of thoroughly softened/creased/fumbled HomeWrap in this fashion? (Preferably not softened by spinning it in the washer, because there's always gonna be washing powder residues left in it, even when washing without powder. They'll brake the surface tension of rain water, making it "more fluid" and form a non hydrophobic gateway between the tyvek fibres. Both would negatively influence the waterproofness). I'd like to buy some HomeWrap on ebay but only if I know that it'll pass the "fumble, then puddle" test.

I use Tyvek HomeWrap for the bottom of my Uber Bivy and have slept all night in a 2" puddle of water with no leaks. I also test it by placing it in a strainer and filling with water. It will sit there with no leaks for days. I just hand crumple my Tyvek. Be careful to not abuse it too much in the softening.

I suspect that you most likely have a small puncture or a seam that is not completely sealed. I can't speak for the postal envelope seams. SeamGrip has worked well for me.

I have had great success with Tyvek for the bottom of my Uber Bivy. However, you will want something more breathable for the top.

Anyone tried dying tyvek? I like to blend in with the woods and the white really stands out.

I don't think you can dye it, but you can do screenprinting on it.

I have someone printing on Tyvek, You have to watch which type of ink is used. Some types will smear.

A guy on the web used to make tyvek poncho tarps that he dyed different colors. A search might yield something.

Thanks todd. A search did yield the answer. Rit dye does the trick according to one poster.

John that tyvek tent looks great! you had mentioned posting how to utilize the full dimensions, could you post them here? I would really appreciate it

anyone know where i can source a 9' wide piece of housewrap in a decent length that wouldnt force me to buy a 150' roll?

"anyone know where i can source a 9' wide piece of housewrap in a decent length that wouldnt force me to buy a 150' roll?"

http://www.antigravitygear.com/tyvek-ground-cloth-by-the-foot.html