Ground Sheets

[Bob Gross]

First of all, let me state that I normally backpack in the national parks of California in the summer, so it tends to be cool and dry, except when it gets cold and rainy. I use a solo cuben fiber tarp pitched no closer than five inches from the ground.

For years, I have used simple ground sheets to keep the soil moisture from getting into my sleeping gear. So, I used mylar space blankets and then simple plastic sheets (window treatment plastic). Neither of these seem very durable. The mylar is brittle and rips up. The plastic tends to get a hole about the size of my boot heel. Currently my plastic sheet goes about 1.3 ounces.

So, what is the state of the art for UL ground sheets?

I notice that cuben fiber ground sheets are sold, and these tend to have bathtub sides maybe 3-5 inches tall, but they weigh three or more ounces. That has the effect of helping keep off rain spray, I guess. Maybe a flat one would be ineffective, even if lighter. We could extend this thinking and do the sides taller, and then the whole thing starts to be a bivy sack, but it gets heavier. I don't need extra warmth for the sleeping bag, so I am inclined to keep it ventilated.

For those of you who use cuben fiber this way, what is the weight of the fabric? Apparently most of the commercial products are about 1.0 ounce CF material. Did anybody try something thinner? How did that work? I know. Cuben fiber is pretty pricey, so you would want it thick enough to last a while.

I was thinking of crafting up one, and I figure that it would require at least two linear yards of material. Also, I am trying to decide whether to hem it by sewing, or hem it by folding the edge and taping, or both. I don't want to end up with an expensive mess that weighs more than my current plastic sheet.

Has anybody been down this road before?

–B.G.–

[Justin Baker]

I can't deal with plastic as a ground sheet. It's so light that if I put my foot down on it, my foot pushes it around with very little effort, difficult to keep it neat and flat.
I like tyvek.
Cuben is an interesting idea, I would be concerned about cost vs. durability.

[Nick Gatel]

Bob,

Don't know that you are going to get lighter than some of the UL groundsheets out there.

I have a zPacks cuben poncho/tarp that converts into a bathtub ground sheet for my Hexamid. Weight is 4 ounces including the clips. I really like it as a poncho, but am concerned that extensive use as a groundsheet will degrade the material. So I only use it for that purpose when absolutely necessary and I need more than just my waterpoof sleeping pad.

Normally I don't bring a ground sheet. My pads are light and waterproof. That being said, I don't have extra surface to place gear and keep it organized as I can do with a groundsheet.

Normally, when I need a groundsheet I use polycro. I bought several of these years ago and am still using the first one — lasts much, much longer than I had anticipated. I have read that many PCT thru-hikers have had one sheet last the entire route.

So I guess for my needs, polycro is state of the art for now.

[Justin Baker]

Nick, has your cuben groundsheet accumulated any pinholes?
I've thought about doing just a sleeping pad, but I never use a full length and my legs would be on the bare ground.

[Nick Gatel]

No pinholes yet — but I rarely use it as a groundsheet. Its a great poncho — not billowy like most and fairly short. The thinner cuben would probably get holes, but I have not read about anyone using the really thin stuff, which is what Bob seems to be looking for — feedback from someone who has used the really light stuff.

[Bob Gross]

"feedback from someone who has used the really light stuff."

Yes, Nick, it would be interesting to know how impractical the super light stuff would be. You are apparently concerned about abrasion. Well, that makes sense. Down where you are, there is a lot of sand and gravel. Where I go, it is half sand and gravel and the other half would be pine needles.

Since my existing polycryo sheet is 1.3 ounces, I would not want to go heavier unless I can get a big boost of practicality, and I think that won't happen unless the sides were pretty tall, which would make it heavier as well.

–B.G.–

[Jon Leibowitz]

I use the GG polycro and have used the same sheet for two summers. Yes, it's insanely light and will fly away in the wind. It can be annoying to set up cause of how light it is. But I love because of how light it is. They last a long time and thus far has protected my SMD serenity net. I give it an A+.

[Bob Gross]

"the GG polycro"

Mine lasted until about the third night of the first trip when my heel went through it. Ordinary tape seems to work on that.

–B.G.–

[Brian Johns]

I have an Oookworks "chicara" floor (it's a spinnaker like ripstop silnylon – I think). Anway, I think my pad-sized (slightly smaller than the Oookwords standard sized tub floor, weighs 3.8 ounces. To me it's very worth it. It's durable – I hike in the Sierras too – and the bath tub sides clip into just about any shelter I want or stake out on their own. Oookworks uses little carbon struts at each of the four corners and this helps to give the tub shape and keep little items on the tub floor for organizational puroposes. Last I read, Sean at Oookworks has been keeping these in stock and, aside from the UK shipping costs, they are pretty reasonably priced. Check'em out.

http://oookworks.com/in_stock.html

EDIT: I should add that mine is 220 cm x 64 cm where is the standard is 220 x 75 cm. Mine is also "chicara" or whatever, which may be the reason I get under four ounces (I don't use a stuff sack) and OW's regular version – looks like 20D silnylon maybe is 5 ounces. Anyway, still can't be beat, at least not for wet weather use. The tub is SOOO much nicer than ground-level tyvek or polycro for my uses.

[M B]

walmart cheap space blanket, it weighs about what polycryo weighs.
polycryo
cuben groundsheet

Adventure Medical Kits polyethylene space blanket is light, cheap, strong, and readily available.

They can all be patched with a small bit of tape if needed.

Then there is the 1/8" thin CCF that can be put under a UL groundsheet to protect it.

[Bob Gross]

"Then there is the 1/8" thin CCF that can be put under a UL groundsheet to protect it."

And then there is probably something to put under the 1/8th" thin CCF to protect it as well.

I'm trying to cut the weight down, not double or triple the weight.

–B.G.–

[M B]

"I'm trying to cut the weight down, not double or triple the weight."

But if its part of sleep pad system, it doesnt add weight.

If use a torso pad and a 1/8" thinlingt, on rocky or twiggy or needly ground putting the thinlight under the groundsheet can protect it.

Quite a few use the 1/8 CCF with thier xlites to protect them.

I used to do that, but nowdays just using my raingear, maps etc under the xlite to protect it. Waterproof paper maps are surprisingly tough.

[Bob Bankhead]

+1 for Adventure Medical's Survival Blanket.

http://www.adventuremedicalkits.com/survival/shelter/survive-outdoors-longer-survival-blanket.html

It comes in 2 sizes. I use the larger one as it gives me extra material to run up the inside of my Gatewood Cape (like a bathtub floor's wall) when the wind changes, or I can fold it in half and get a double thick floor for when I'm forced to set up on really soggy ground.

60 x 96 inches; 3.2 ounces, $7

56 x 84 inches, 2.9 ounces, $5

[Justin Baker]

I don't understand how you guys can deal with space blankets. They are so crinkly and annoying!

[Shane S.]

I have used the same polycro ground sheet for 2 seasons now and I dig it. I also put my 1/8" thinlight pad between the polycro and the tent floor for better puncture resistance. Works well.

[jscott]

The first trip that I used polycryo I tore a sheet up pretty good. I used rocks to hold it down in the wind; it ripped on the edges.

Since then, having learned to baby the stuff, I've been able to get a full season out of a single sheet. I think polycryo is great. But it is annoying in wind.

[Rick Adams]

if you can overlook the downsides of polycryo it's probably the best from a weight vs value (durablity and price) perspective. My understanding, without any firsthand knowledge, is that cuben lighter than polycryo is prone to pinholes. To me, the major downside to polycryo or sil is that once my weight is disbursed over the area of a big comfy sleeping pad the groundsheet becomes a sled. If cuben would not become a sled as easily it might be worth a minor weight and major cost penalty. Of course, I've never once found a flat spot worth sleeping on.

[Bob Gross]

If I make something new in a ground sheet, maybe I should build in some little bubble levels to the edges.

–B.G.–

[Rick Adams]

you could revolutionize the backcountry groundsheet industry and gain unimaginable wealth….or maybe not

[Bob Gross]

I was looking at cuben ground sheets. I start out thinking that the normal size is about seven feet long and from two to three feet wide, often narrower at the head and foot.

Immediately I see two distinct types. One has the plain flat shape, and one is built with bathtub sides. Bathtub sides add a little weight, mostly due to corner construction. In commercial products, the bathtub sides tend to be three to five inches high. This would help if there was a breeze or rain splash near the ground.

Somebody out there has probably done this. What is best? Flat, three inches, or five inches?

I anticipate not connecting this thing to the tarp.

–B.G.–

[Dale Wambaugh]

If you are going to have tall bathtub sides, you might as well get the bug netting too and have a double wall setup. Taller sides will block the wind and make your setup much warmer. The bug netting becomes the rigging with benefits.

So I say all or none– the lightest ground sheet possible, like polycryo, or a net inner. You can use the net inner alone on nice summer nights as well.

[Bruce Tolley]

Prolite Gear sells spinnaker cloth by the yard that holds up pretty well. Much lighter that Tyvek but a bit heavier that polycro.

http://www.prolitegear.com/base_designs_pro_spinnaker_cloth.html

[JCH]

I too have been using the GG PolyCro sheets when I wanted a UL Groundsheet. Never had it rip or puncture…seems pretty bullet-proof. But because it is so light I *have* had problems with it blowing in the wind, and when it gets wet it can be difficult to deal with.

There is a thread on here about people making PolyCro tarps and they mentioned Duck Brand window film. On a whim I picked this up from WalMart http://www.walmart.com/ip/Duck-Brand-XL-Heavy-Duty-Patio-Door-Window-Shrink-Kit/26977958

Double thick. First impressions are it is MUCH stronger and probably easier to deal with when wet. I cut a 7' x 5' piece for use under the Zpacks Duplex and it weighs just under 3 oz. A "normal" solo size would be less than 1.5 oz. Might be an option for some.

[Bob Gross]

I used similar dimensions to the Zpacks cuben ground sheet in 0.74. Four inch bathtub walls. Taped, not sewn. The finished weight is 2.37 ounces.

The bad news is that it weighs one ounce more than my existing flat plastic ground sheet. The good news is that it is more functional with the bathtub walls, and it is going to be hard to put a boot heel through it. It seems like tough enough stuff.

No matter whether it is plastic or cuben fiber, the wind will blow it around.

–B.G.–

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