Groundsheet puncture resistance

Mike:

Any sheet that's light enough to backpack with is not going to offer reliable puncture resistance. Fancy and expensive fabrics are more about retaining tear strength while cutting weight — not about puncture resistance! As an example, I once had a rogue cactus "leaf" pricked right through my REI Half Dome footprint, tent floor — and my finger — drawing blood! And the REI fabrics are thicker, heavier duty than all UL equivalents!

A better way is simply to continue carrying an UL groundsheet — primarily to keep the tent floor cleaner and drier and only secondarily to protect against sharp objects — and spend a few extra minutes on careful site selection and clearing out rogue objects.

That said, and given what you wrote above, I highly recommend the ultralight and ultra compact GG Polycro sheets.

At 84 inches long, the Gossamer Gear spinnaker sheets are about 24 inches shorter than a 2C and 50 inches shorter than a 2R … Warmlite's other models are longer. If you feel you must have a "waterproof" outside groundcloth, consider silnylon 2nds available from Thru-Hiker and several other sources.

But also consider uncoated fabric for an outer groundcloth used to ward off abrasion. It's much better to allow water to do what it wants to do … soak into the ground.

Adding to my post above…

Many hikers dispense with groundsheets altogether. Hilleberg tentmakers, for example, will tell you that they don't carry groundsheets either! Spending just a few more minutes on site selection and clearing can mean one less thing to bring and deploy.

But for me, I do use a groundsheet — but again, primarily to keep the floor cleaner and drier. If you choose to do the same, then I would again recommend either polycro (maybe look for larger size) or simply cut a 2-mil plastic sheeting (aka painters cloth) to size. A roll costs $2-3 and you can make two groundsheets out of them. Cheap as heck, but slightly heavier and less robust than polycro.

To me, an uncoated groundsheet defeats the purpose — at least partially. My plastic groundsheet blocks ground condensation from wetting/muddying the outside of my tent floor — which keeps my tent cleaner and easier to pack. Also, a wet groundsheet is much easier to dry — or simply to fold against itself and pack away. OTOH, with an uncoated groundsheet — you will just have two wet things to pack away (or air dry) — both a wet groundsheet and a wet tent floor.

As for water getting underneath your tent floor — rain water will not get between your tent floor and groundsheet if you cut your groundsheet 2-3 inches smaller than the floor all around. The only exception is if water starts pooling underneath because of careless site selection. In that case, it doesn't matter at all whether your groundsheet is coated or uncoated — or even if you use one at all…

A tip I've used, recommended to me by Stoveman, is a Gossamer Gear 1/8" thinlight pad underneath the Groundsheet.

Dimensions are 50cm x 150cm and weight approx 50g – One is enough to cover the area you mostly sit or lie on or two gives coverage for most of the floor area. This offers good protection as well as an appreciable extra bit of insulation.

The folks at Winwood Outdoor got me mine and though it's not a usual stock item they added some to their GG order for me. They may even have one or two in stock so could be worth an enquiry if you decide that's a good way to go.

Mike, spinnaker fabric is verrry fragile. I sliced right through my GG whisper pack with a finger nail while stuffing some gear into it. On the other hand, polycro is pretty durable; I've been using the same piece for two years now and have yet to puncture it. Partly because I spend some time clearing the area of twigs, stones, and cones. If you're going to be pitching up directly on granite, the polycro may still be a benefit.

Nm

Let me start by saying that I don't consider there to be one Right Way to use a ground cloth and for me, this discussion is not a "you're wrong, I'm right" thing. Just presenting options.

For the record, if it's just me Apr thru Oct in the northern midwest, I prefer a floorless shelter with a 27"x84" groundsheet under my pad and yes … good site selection is imperative.

Ben says But for me, I do use a groundsheet — but again, primarily to keep the floor cleaner and drier. He's correct for those objectives but a clean and dry exterior floor just isn't one of my own priorities … the readers can/should decide their own objectives (HYOH).

Ben also says As for water getting underneath your tent floor — rain water will not get between your tent floor and groundsheet if you cut your groundsheet 2-3 inches smaller than the floor all around. The only exception is if water starts pooling underneath because of careless site selection. In that case, it doesn't matter at all whether your groundsheet is coated or uncoated — or even if you use one at all…

The perfect site is more or less level and soft ground the size of your shelter that slopes away on all sides, right? I think I've seen about three such sites in my life and two of them were in REI showrooms. Some "highly managed wilderness areas" require camping at established sites. If the vegetation is dense in the area you have no choice but to camp on frequently used tent sites. Many decent sites are still less than perfect over some portion of their footprint and water can certainly get between tent floor and groundcloth.

WHEN I use a groundcloth along with a floored shelter is to use one that'll withstand a higher hydrostatic head than the tent floor, cut it about 6 inches larger on every side and place it inside the shelter. For myself, that'd be when using traditional double walled tent … which isn't so often. But it IS as close to bombproof and immune to poor site options as you can get.

I am getting in late on this thread-oh well. I have tried many materials for groundsheets: tyveck, golite poncho/tarp, golite groundcloth, Lynne Wheldens sail groundsheet with torso coverage– all light weight. But I think my favorite is maid by Equinox Ltd. a 90×42 inch- with four tie-outs for stakes at nice 4.4 oz. Very, very puncture resistant. I have used it many times for my hikes and have never had a puncture. At 90 inch by 42 inch thats alot of ground coverage for 4.4 oz. My 3 cents!

I have been using standard silnylon for the groundsheets in my tents for years. So far I have made only a couple of very tiny holes, easily patched. Didn't make any holes in France over 3 months.
But the silicone layer did start to get a bit worn – again easily fixed with some stock silicone sealant spread thinly.

Cheers

To answer your question:
I have found that medium weight painting drop cloth plastic sheeting is about the most puncture resistant lightweight material available – and it's CHEAP.

Eric

But the silicone layer did start to get a bit worn – again easily fixed with some stock silicone sealant spread thinly.
Roger do you mean something like silnet seam sealer? Do you spread it thin by diluting it with something? My Terra Nova laser groundsheet, which I think is silicon coated has lots of pin holes from Pyrenean sharp grass.

I want to protect the groundsheet on my new expensive Warmlite tent. I intend to use it on pitches that may be rocky. So i'm looking to use a lightweight footprint.
What has the best puncture resistance for use as a footprint? I'm leaning towards the Gossamer Gear spinnaker sheets, as i think that is more puncture resistant then polycro.
Any suggestions?

Mike I agree with Benjamin any light footprint will not be puncture proof, so how about a thin transparent polythene sheet? It provides a bit of abrasion resistance, it is cheap but most importantly if cut to your tent footprint you can lay it out first and feel and see how sharp things will affect your precious new tent, and move your pitch easily to avoid things.

Hi Derek

What happened was that after some extremely heavy rain we found that some teaspoons of water seemed to have got in, and not by condensation. We decided that the silnylon groundsheet, which by now was several very active years old, was starting to leak at small wear spots. Nothing obvious – no holes or rips, just slow abrasion. Remember – the tent had been in use in France for about 6 weeks straight at this stage, plus several years in Australia.

> do you mean something like silnet seam sealer?
Actually, it was some bathroom silicone sealant I found in a hardware shop in Courmeyer in Italy on the TMB. I couldn't find any McNett stuff there.

> Do you spread it thin by diluting it with something?
Oh, that I could have. But I couldn't find any suitable solvent in small quantity, so I spread the groundsheet over the wide balcony railing (hotel in Courmeyer: big ski town) and spread the sealant thinly over it area by area, with my fingers. Best I could do at the time. Took some time … after which we went and found an Italian Pizza restaurant.

> My Terra Nova laser groundsheet, which I think is silicon coated has lots of pin holes from Pyrenean sharp grass.
Could be.
But let me introduce you to Spinifex grass from inland Australia some time: it goes through leather and canvas. :-)

Cheers

Thanks for the replies folks. I’ve never used a footprint with a tent before, but i’ve never spent as much on a tent before either!
I’m not too worried about keeping the floor clean or dry. It’s puncture resistance i’m trying to beef up. I intend to use the tent in high mountain pitches, so the ground may be less than ideal.
I’m glad i posted the question, as i’ve saved myself the price of some spinnaker. I haven’t handled spinnaker before, and didn’t realise it had poor puncture resistance.
I understand that any lightweight ‘footprint’ material will not be super strong, but a little help is better than none.
I’ve used my Laserlite for years in the mountains without a groundsheet, and haven’t had any problems. It’s easy to find a good spot for the small Laserlite. The R2 is much bigger than the Laserlite though.
I’ve got myself some of that ‘secondary’ glazing plastic sheet, and it seems pretty tough. I believe it is the same as polycro, so will give that a go.
Cheers.

I’ll think about the ID groundsheet as well David. I’ve also spotted some 3.mm foam tent underlay that would also add insulation on snow. It comes in 1m or 1.5m rolls and is sold by the metre. It is made by MULTIMAT in the UK.

Mike,

Here is a link to a thread on groundsheets that took place a few months ago. Some good info here.

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=14322&disable_pagination=1

Jay, do you still use your Equinox Ltd. 90×42 inch- with four tie-outs for stakes 4.4 oz ground sheet?

Why do you prefer about it over Tyvek and Polycro?

The weight seems to be only a little less, perhaps an ounce or less, than a similar Tyvek sheet I've weighed with corner bungee cords and plastic hooks attached (meant to connect to pole bottoms).

I'm trying to figure out the best combo of utility and weight for a ground sheet of about 81.5 in. x 51.5 in. to protect the bottom of a silnylon tent. The Tyvek sheet with corner bungee cords and plastic hooks at that size weighs 4.8 ounces. A similar Polycro sheet WITHOUT corner bungee cords/hooks would be about 1.5 ounces (allowing for a slightly larger size to accommodate potential shrinking in hot weather).

According to Thru-hiker, 1.1 oz coated silnylon weighs 1.35 ounces per square yard. According to that, a ground sheet in my size would come to 3.5 ounces without any bungees or hooks (which is fine), and would save only about an ounce over a similarly sized Tyvek sheet. Tyvek also seems like dirt would stick to it and it's not waterproof. Polycro is waterproof and a lot lighter, but it sticks to itself and I wonder how easy it is to work with in the field.

Right now leaning toward either Polycro or silnylon, without any corner bungee cords or hooks, which seem unnecessary to me. Looking for the lightest waterproof and easiest to work with option.