Space Blanket / Ground Sheet

[Casey Ryska]

Does anyone have any experience using an emergency space blanket as their ground sheet while tarp camping?

[Scott Peterson]

I cut one to go under my BD tent last year for a trip into Lassen National Forest. After 4 nights of camping in everything from sand to pine needles, I had no problems. If you take care to move sharp objects as you should anyway, the mylar resist puntures pretty well. Bring duct tape for any emergency repairs.

[Dondo .]

I tried half a space blanket with a tarp and didn’t much like it. It was too flimsy and crinkly for my taste and was a pain to fold back up. On the other hand, I had a converstion with Golite’s Coup last week about poncho/tarping and found that he likes space blankets for tarp camping and finds them plenty durable.

[Dale Wambaugh]

BAck in my BUL (before ultralight) days, I used the Sportsman’s model Space Blanket for a ground sheet and that worked very well, but they are something like 12oz if I remember right. It would be nice to see them make something lighter, but still have some reinforcing fiber.

[cary bertoncini]

very, very light

true can’t fold them up like new, but still pretty damn small

i have been using the free ones i got from completing marathons

[Dondo .]

Yeah,Dale. The Sportsman’s Blankets are great. I use to use part of one as a ground sheet but stopped doing so because of the weight. Something like it but at half the weight would be ideal.

[Antonio Abad]

It proved too noisy for me. Any movement would result in that loud, crinkly noise and would keep me up. I have since switched to window insulsation plastic for my groundsheet. It has just about the same weight and durability characteristics of mylar sans the noise and the dual-use capability.

[Casey Ryska]

Thanks for the replies.

Durability and noise definately seem to be an issue. I’ve seen some space blankets that have tyvek on one side and the reflective material on the other. I wonder if these would solve some of the problems. For those of you who have tried it, did you notice any insulation value in useing a space blanket at a ground sheet. I.E. heat being reflected back up to you.

[Kevin Vandergrift]

I use a mylar space blanket for my ground sheet and although it is noisy, it is also very light. My sheet is cut to approx. 96″x 48″ and weighs 1.13 oz. They are also very cheap and can be easily replaced when they become useless.

[cary bertoncini]

i have used the polycryo groundsheets from gossamergear – i have noticed that the ground seemed colder than when i was using the space blanket for groundsheet. i think it does reflect some heat.

[Scott Peterson]

I seriously doubt you are going to realize any noticeable heat reflection…especially if you are on a pad of some sort and inside a sleeping bag. The emergency blanket I purchased from REI is not noisy after a couple of uses. Tyvek stays way noisier for far longer and is far heavier. If you are looking for a lightweight ground sheet to keep your stuff clean and dry…Mylar is great. It is so inexpensive that I would recommend you go buy one and try it in the back yard. When you can get a 8 foot by 4 foot tarp for 1.13 oz….what else do you want?

[kevin roberge]

has anyone tried using these reflective blanket things as shelters? Do they have a temp rating? I know they’re reputed to cover you in sweat (not terribly desirable), but they seem like a potential super-duper-ultra-light sleeping system. (I should qualify that I mean the mylar ones that weigh about 4 oz)

[Jim Colten]

Tinny at minibulldesigns reports that he’s been OK down to 45-50F in the Thermolite Bivy from adventure medical kits.

Mind you that he’s a northerner (Maine). YMMV

[Vick Hines]

Yes, I’ve used emergency blankets as shelter. Reinforced the edges and made pullouts with narrow fiberglass strapping tape. Noisy. Very noisy. But servicable for a super light shelter.

[D Apron]

I have used “space Mylar” for a long time by taking a normal size and folding it over 2 pieces of 3/8″foam. One for sholders and one for hips.
I tape the foam in place, then fold the remainder over. then I tape the edge. I use Mylar tape. This gives me a double layer of water prof, full length portection.
I notice a great amount of cold ground transmission at my waist area if I do not have somthing to palce under my waist area, such as a shirt.
Somehting under the legs helps also, but is far less important.
If I choose to patch, I use Mylar tape. Usually the assebley lasts 6 to 10 nights. The foam is reusable. The noise is of no concern after a full day fast packing.
I have often thought pine neetles would punch many holes in it. Were I hike it is all rock and or sand (desert) so I have not verrified this concern.
I am constructing a Tarp Shelter for experiment. I am reinforcing edges with Mylar tape and integrating string line for tension, just like a comercial tarp. I anticipate the noise, during wind, will render it usless, not to mention destroy it in short order. We will see.

[Anonymous]

My experience with a mylar space blanket is noisy, noisy, noisy. Try it and see if you like it.

[Gene .]

What about making a ‘mylar/space blanket’ sandwich between 2 sheets of polycycro? Just spray some 3M 77 on both cyro sheets and place the mylar on one, cover with second sheet run through rollers. Now that would be a reflective groundsheet, that cut to size, would be worth it’s weight in the shoulder seasons.

If not why?

[Scott Peterson]

I have successfully used a mylar emergency blanket cut to size as a tent footprint for a total of 8 nights with the same piece. I have pitched the tent on both sandy and high needle/duff sites and while sharp objects have left impressions in the material, there are no major holes. It also gets very “quiet” after a couple of nights use. I cannot speak to the heat reflective properties, but it is remarkably durable for it’s weight, given my application.

[Douglas Frick]

> If not why?

Radiant heat barriers (space blankets) need an air gap between the heat source and the reflector to be effective. A space blanket sandwiched between two polycryo sheets will still conduct heat very well when you lay on it. For non-emergency use, the best plan is to bring sufficient insulation against conductive and convective heat loss to the ground so that there is no significant radiant heat to be lost. (Cold fabric, i.e. the outside of your sleeping bag or the bottom of your sleeping pad, is not a significant source of radiant heat.)

IMHO, space blankets are generally advertised for emergency use because that’s precisely when you aren’t likely to have sufficient insulation to prevent convective heat loss (i.e., to the wind), so when you wrap a space blanket around yourself you will reduce convective heat loss and have the crucial air gap to allow the space blanket to reduce radiant heat loss from your warm body. That’s why you usually see sketches of people hugging their knees: laying down would increase conductive heat loss and remove the necessary air gap underneath the body.

The best place for a space blanket is on the inside bottom of an air mattress (I don’t know why manufacturers don’t have that as an option; I suppose adding down is lighter?), or slung under a hammock. Just laying on one isn’t going to do much for you, IME.

However, two sheets of laminated polycryo might last longer than two individual sheets used one after the other. I have had great success using a single sheet of polycryo, but on the last night of a recent trip a two-inch tear in the edge of the sheet instantly turned my large polycro ground cloth into two odd-sized small polycryo ground cloths when I shook it out :(

[Eric Eaton]

I've used them cut down to size.

Not bad, if you don't mind the racket.

Also, I once got a batch for around 50 cents apiece at a clearance store. Brought one on an overnighter without having a chance to cut it down. When I arrived at my campsite and tried to unfold it, the thing just stuck together in places and shredded into unusable tiny stripes, bits and pieces. Had to sleep with a duff bed under my quilt.

Hope this is helpful.

Eric

[Joe Rio]

I used a space blanket [military] in the mountains of Ga. along with a poncho and it worked great. Whether rain or drizzel it held the heat nicely. Don't know about real freezing weather though. We slept on them for weeks and even while soaked and lying in deep moss it was warm.

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