Ground Cloth for a Pyramid…Need Advice

[Chris Roane]

My general plan is to purchase a 10×10 oware pyramid tarp, with perimeter netting. Now I need to figure out what to use for a ground cloth.

What I want to accomplish is pretty close to the same level of protection as a full tent. In getting the perimeter netting with the pyramid, there will already be elastic hooks on the inside of the pyramid. My idea is to get a ground tarp that I could then attach to these hooks and basically make a waterproof bathtub floor for total water protection.

But what I am confused on is what type of material to get for the ground floor. It needs to be 100% waterproof as the areas I go can get a lot of rain and the people sleeping in the shelter will not be using a bivy for their down sleeping bags. I thought about going with tyvek, but I am hearing that it is not 100% waterproof. So I am leaning more towards silnyon. But there appears to be several options, and I really don't know what would be best when considering weight and durability. If you have any advice on exactly which material you think I should go with, please let me know.

Any thoughts/opinions would be appreciated!

[jeffrey bennett]

Another thought is to use the polycro ground cloth. I just got my mld speed mid with the netting and my plan is to use 2 polycro tape together. Both MLD and gossamear gear carry them. I have gossamear gears version.
Jeff

[David Chenault]

Chris, I suspect that with reasonable site selection you won't need one.

[Chris Roane]

I've considered polycro, but I've been told that some people don't like it for how much sound it makes with movement. This wouldn't be a huge deal, but with four guys sleeping in the same shelter, I could see how this could be annoying.

[Chris Roane]

I thought about that too, but sometimes there aren't that many great options in where to setup the shelter. Having a ground tarp of some kind would also make the "tent" dwellers feel more comfortable in sleeping in this shelter.

But bringing the floor will be considered on a per trip basis. I just want to have the option of having it.

[j lan]

Yep, that was my experience with polycro this last trip, noisy with 3 people on it. I would say silnylon. Doesn't need to be the whole size of the tent, maybe leave bare ground right by the door and attach it on the other three sides? going to get a lot of grit/rain etc by the door and a 10×10 is pretty dang big.

I also own an exped multimat which is really great in the shelter and also for boosting your pad rating for winter camping. Multimat

I have used this as a floor before, it was nice.

[Chris Roane]

James: That's a great idea about the size of the tarp! What kind of silnylon would you recommend? Would 1.1 be too light for this purpose?

If I went with silnylon, how would you suggest I create grommets for the tarp connection to the shelter?

[j lan]

I wouldn't use grommets, the clips are already on elastic so all you would need is a little webbing loop, i think 1.1 would be fine. Just bring a little seam seal with for small holes or just use duct tape. Tons of people here use 1.1 floors with little or no issues. Weight will get kinda crazy going up the scale on silnylon and i don't really think it is all that worth it. Who cares if the floor has some patches or seamseal spots, it's not your roof.

[Chris Roane]

Fantastic!

I found what I think is a good option for the 1.1 silnylon: http://www.questoutfitters.com/coated.html#SILNYLON 1.1 OZ RIPSTOP . I would go with the 2nds @ $6.30/yd.

I probably would fix the holes at home with the seam seal, and patch any holes on the trail with duct tape that I will have anyway. We usually don't camp on anything too sharp, so this should work fine.

As far webbing loop…would this be something like a nylon webbing (like this: http://www.questoutfitters.com/narrow_roll_goods.htm#WEBBING- NYLON)? How would I attach this to the silnylon? This is all new to me! I appreciate you answering my questions.

[Diplomatic Mike]

Polycro doesn't make any noise! WTF are you guys sleeping on?
I've been using Polycro/Window insulation film for years without any problems.

[j lan]

Gossamer Gear polycro, you won't notice it by yourself, but when someone else is in the tent sleeping on it it is kinda loud. Verified by 2 other people other than myself. Polycro is great, no knocking it, just saying 4 squirming sleepers in a chamber might up it a bit.

[Mike Knapp]

I made a silnylon footprint by double-rolling all the edges and then sewing loops made of grosgrain ribbon on the four corners and on the middle of the long sides. (If you haven't ever worked with silnylon on a sewing machine, it isn't that hard.) I used little pieces of elastic cord and "mitten hooks" on the ends for clips to attach to my tent.

Finished size is about 7 feet by 4.5 feet, and it weighs about 6 oz.

I can post pics of my seams and loops next week if you want. Nothing pretty, but it works. You should also be able to find details on how to do a double-rolled edge and corner loops on the MYOG area here on BPL if you need help on that.

[Chris Roane]

Thanks Mike! I'll probably give this a try in the coming months.

[Steve O]

I have tried polycro but prefer tyvek. I used the "homewrap" with my pyramid shelter through everything save a flood and it performed great. Its dry and VERY puncture resistant. May not be the lightest but theres no noise.

[Steven Paris]

What about making four simple "curtains" out of sil or tvvek that attach to the hooks, hanging down enough to drape on the floor as spray guards? Then each person using the shelter gets a polycro gs. I spent a rainy night under a trailstar recently and appreciated having some bare ground under half of the shelter. This would be a modular system, so you control the floor weight depending on how many people are going and if it isn't raining then the curtains could rolled up and left in the pack.

[d k]

Well, we've used Tyvek for the past few years in the Sierras with our Tarptent, with no problems with moisture. That said, the rainstorms don't generally last more than a few hours, though we've been in some good downpours. I think if you're not in flowing water, that the overhang from the tent should protect the edges of your "bathtub" floor. I haven't noticed dampness from merely moist ground seeping up through Tyvek. And it's durable, not noisy, and not slippery – just a little heavier than the other options stated here.

[Fred eric]

For my wife and i we use :

mild or good conditions :
suluk 46 plastazote foam :
1/8" X 24" X 72" – 1.9 oz (54 grams)
directly on the ground, mine being used during the day to protect my fishing gear

if heavy rain , or if camping on spongious soil expected we use a 1,4m x 2,5m 1.1 silnylon ground floor
i sewed some tieouts on it to pitch it in a minute if needed to make a shelter during the day for a short pause.

[David Olsen]

+1
Only closed cell foam full length most of the time.

Add silnylon or tyvek ground sheet if going someplace
muddy.

Add bivy if going someplace buggy or snowy.

[Lawrence Vito]

I am used to tents with floors and I am having a hard time with the no-floor concept. So I am making a silnylon groundcloth for my Ti Goat Vertex Tipi right now and this is a very useful thread to me. I tried Polyco and found that it slides around too much and is noisy too. I have cut a piece of silnylon and will be attaching bungee to it that will connect to the stakes so that it will stay in place. Right now the ground cloth is about 2" smaller then the perimeter, but I think it needs to be smaller so drips go onto the ground and not the groundcloth. Because of the pitch of the side walls, I can't get my sleeping bag right right up against them, so it seems like I could get some weight savings by trimming the whole thing so there is about a 6" perimeter all around. is that too much? I am also thinking that having a full ground cloth negates the benefit of being able to walk into your shelter with shoes on, so I am thinking about cutting out 1/4 of the "pie" (the tipi is almost a round shape) exposing 25% bare ground on the left side of the doorway because I need the full length on the right side to stretch out. I am not too happy about the added weight. Right now before further trimming, seam sealing and bungees, the ground cloth weighs 8 oz.

Does anyone have any comments or suggestions about how much space to leave around the perimeter and how much bare ground there should be?

Thanks for reading.

Larry

[Travis Leanna]

Larry,
your question is really based solely on your individual needs and preferences. However, I'll add my thoughts on it.

Since you're unsure of the shape and size you'll like, I'd suggest starting with a full groundsheet 4-5 inches smaller than the perimeter of the tipi.

Take it on a few trips and evaluate it's performance and your needs.

If rain gets on the groundcloth, maybe cut it a *bit* smaller. If rain wasn't a problem, maybe leave it alone.

If you wished for more bare ground the entire trip, maybe cut a 1/4 section out like you said.

Take it out on another trip, and reevaluate. Repeat as necessary. Sometimes its hard to figure out what we want just by hypothesizing.

Good luck!

P.S. you could omit the bungees and just use rocks/gear to hold the corners down.

[Rick Dreher]

Hi Chris,

I use a cut-down Neatsheet in my GoLite Hex. It's basically two layers of soft, Tyvek-like material that has proven sufficiently waterproof in the conditions I've encountered, It's also non-slippery, silent and offers a bit of warmth.

I do not know if it would wet through in truly soggy conditions.

Cheers,

Rick

[Aaron Reichow]

In my somewhat limited experience, Tyvek and 1.1 oz silnylon are similarly waterproof. No, Tyvek isn't absolutely waterproof- but neither is silnylon. If it were me, I'd go with Tyvek mostly due to cost and ease of folding. If the not-quite-waterproof qualities of Tyvek and silnylon are showstoppers a more appropriate option might be urethane coated nylon or polyester:

http://www.seattlefabrics.com/nylons.html#poly ctd rs
http://www.seattlefabrics.com/nylons.html#1.9 oz Urethane Coated Polyester Ripstop

[Chris Roane]

Larry,

I am debating with the same thing with the ground cloth. What I am going to do is get a 8×10 foot ground cloth and connect it to the inside of the pyramid shelter (where the bug next will be connected anyway….my pyramid is going to be 10×10 feet). This will create a bathtub floor effect on three sides, and my hope is that the condensation from inside of the tent will drip on the outside.

This should also provide a space to walk into the shelter without walking on the ground cloth.

Rick: How much does your Neat Sheet weight? It is inexpensive, but how durable is it? It looks like it would weight quite a bit for the size I am looking for.

Aaron: I have come to the similar conclusion that tyvek and 1.1 sylnylon are very similar in waterproofness. But the big thing for me is the weight savings with the sylnylon.

[Kevin Egelhoff]

Our group of (6) using 3 large Gossamer Gear Polycro gound sheets (2 people on one large sheet) have over 60 nights using these in our Mids for the last 5 years and I have never heard anyone complain or have an issue with noise ???
I'm a super light sleeper too. Other guys snoring …. an issue yes, but not these!

[Dale Wambaugh]

Tyvek. You can cut and tape it to make a bathtub. It will be waterproof enough unless you have outright streams under the floor.

For just a general ground cloth, it sounds like a 10×10 silnylon tarp would do the trick. Could double for a sun/rain shelter for cooking and eating. Keep in mind that a 10×10 tarp may be a little smaller— "finished" size issues.

With that many in in the party, one hiker could carry a cheapie blue poly tarp for the "expedition." Get a 12×12 and hack it into a bathtub floor with scissors and duct tape. Use it for a drop cloth, etc when you get home.

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