Window shrink insulation as ground cloth? Same as Gossamer Gear Polycryo?

I believe I have the interior kit although the package I purchased didn't really seem to indicate whether it was intended for exterior use or not. I have spent a handful of nights on this material and I have developed quite a bit of confidence in it. I would think as long as you removed sticks and pine cones that you would be perfectly fine putting your airmat directly on the film.

I have also wondered if the window shrink insulation was the same as the Gossamer Gear Polycryo sheet. I have been using the window shrink outdoor insulation as a ground cloth for the past year and it has handled a wide variety of conditions so far. And oh, so light! I recently read that the window shrink indoor insulation is supposed to be stronger but the outdoor stuff has worked so far. I am still curious if it is the same stuff as Gossamer Gear's Polycryo sheet though.

I have been using Duck Brand window film insulation. I can't tell the difference between it and Polycro.

It comes in multiple sizes on Amazon (http://www.amazon.com/Duck-1299529-Indoor-5-Window–210-Inch/dp/B000NHY1P0/ref=sr_1_6?ie=UTF8&qid=1339044703&sr=8-6). My local Home Depot and Ace Hardware didn't carry any window film when I looked back in March.

I am also now using the Duck brand shrink film. Best deal.

Seems to work well. I also use a NeoAir, but my NeoAir has one extra level of protection as I sleep with it inside of a TiGoat bivy with a silnylon floor.

I think this stuff works fine as a ground cloth with a NeoAir as long as you do a good job of completely clearing the area of any sticks, pinecones, acorns, pebbles, etc. If that isn't possible, at least put a layer of leaves or pine needles over where you are going to put this.

Because this stuff doesn't breathe at all, expect the underside to be very wet from condensation in the mornings. No big deal as you can shake it out and hang it to dry while you eat breakfast.

“Should I go for the "inside" or "outside" window kit and why?”

The ‘outside’ version is thicker and heavier than the ‘inside’ version.
The ‘outside’ version takes up more volume in your backpack.
I think the GG stuff more resembles the ‘inside’ version.
So how durable do you want it? That ‘outside’ stuff is strong!
I just take the ‘inside’ stuff since it lasts long anyway and takes up less space.

Ditto on the other remarks of moisture on the bottom. It’s a moisture and dirt magnet. But for the weight and strength, it’s worth hanging it out on a tree at lunch break, let it dry, and shake off the dirt.

-Barry
-The mountains were made for Teva’s

Edit: be sure to allow for shrinkage when drying in the sun. I.e., cut bigger than needed.

Thanks to all for the replies. Most helpful! Sounds like the "inside" stuff is the ticket for me. Now, for a trip to the hardware store…….

I also use "inside" window film as ground sheet, and have always heard it's identical to "polycryo" from GG. Works great–surprisingly durable. I consider lack of breathability an advantage–I want my ground sheet to be waterproof, and I certainly don't want ground moisture in my sleep system (I use a floorless shelter).

Thanks for the additional input, David. I'm excited to try this stuff.

Rusty,

I used my window insulation to make a tarp out of and it's been holding up just fine. I also use a small piece as a ground cloth.

I LOVE this stuff.

Generally the answer is yes. Polycryo is industrial grade shrink wrap. There are different formulations available, including different material properties and thicknesses. We get ours on huge rolls, then cut and package it.

Oh yeah, and I did get the idea years ago from Dan Johnson's brother Don 'Photon' Johnson…

Thank you Dan for your input. And thank you Glen for the clarification.