View Full Version : Space blanket as ground cloth/insulator?

06-15-2019, 15:44
Has anyone done this with good results? I need a warmer pad but don't want to buy yet another pad. I have read that sleeping with a space blanket on top of you is not ideal, but maybe under you is better. ?

Feral Bill
06-15-2019, 16:05
Zero insulation of heat conducted to the ground. Maybe a useful groundcloth.

Five Tango
06-15-2019, 19:40
If you will check out Evans Backpacking on YouTube,he uses a piece of Reflectix on the ground as part of his sleep system.It's the silver stuff that air conditioning ducts are wrapped in.Lightweight,Durable,fair insulator,and leaves will not stick to it.I would use it under an insulated pad for extra warmth or as a vapor barrier but it is generally available in narrow widths.Tyvek house wrap is frequently used as a ground cloth as it is much lighter than the standard Walmart blue tarp.I would think the average mylar space blanket would be a shredded mess in about 2 days.

06-15-2019, 19:57
There are three methods of heat transfer--convection, conduction and radiation. A space blanket is designed only to radiate heat back to you when you drape it over yourself. It will radiate some heat from below you, too, but it certainly will not stop conduction. You need an insulator for that. (Puffy insulation (mainly above you as you sleep) is designed to stop heat transfer through convection.)

I also have a roll of Reflectix for winter and snow camping. Great stuff to augment the regular pad.

06-15-2019, 21:53
In winter when pushing a sleep system's warmth rating I'll augment with an aluminized mylar or polyester "space blanket" used underneath to radiate heat back. They are also WP more so than well used Tyvek. It's not far off in wt from polycro which radiates back less heat and is less bulky than either. They are also less slippery than polycro or silny.

06-16-2019, 10:01
Has anyone done this with good results? I need a warmer pad but don't want to buy yet another pad. I have read that sleeping with a space blanket on top of you is not ideal, but maybe under you is better. ?

I have used a space blanket as a reflector of heat beneath my inflatable pad on a few cold nights (<20 defgrees farenheit). I'm not sure if it made any significant difference and it was ruined after a few nights (torn). Probably not worth the effort.

06-16-2019, 10:27
I've used reflectix under my air pad for a bit of additional insulation, and as protection for the pad. Used in on the ground and in the hammock. It definitely adds some r-value to the set up, however it's squeaky and slippery. I've gone back to using a z-rest or evasote pad under my inflatable.

06-16-2019, 10:38
Thanks for the ideas!

06-16-2019, 12:59
... I need a warmer pad but don't want to buy yet another pad. ...

This implies you have more than one pad? Stacking them could be an option depending upon what you have. If that doesn't work, buying a warmer pad will be your best option.

06-17-2019, 05:44
I've used the sol brand emergency blankets for many years. as a ground cloth, very tough stuff.
And easily repairable with duct tape should you get tear or puncture (Usually from draping it over bushes to dry in a wind) . Unlike tyvek it is waterproof.

They have gone 50 nights or more before I replace them, as the silver wears off eventually, and it is a backup emergency blanket after all.

I suspect the vapor barrier and wind protection warms a person more than the silver heat reflection quality.

I've used the reflectix, 25 inch wide . And found that it takes two layers to retain any heat. Not really practical for a backpacker as they are so bulky.

Five Tango
06-17-2019, 08:57
SOL makes several different products and they are all better than what we think of when someone uses the term "space blanket" which is usually the cheap mylar film you see at Walmart.

I have used the SOL Escape Bivvy with good result to boost the efficiency of my 20 degree top quilt.I do own their more heavy duty blanket but don't really need it with my hammock set up.A small piece of 16x24 piece of reflectix is all I really need in the hammock.With a 3/4 length underquilt most hammockers use it under their feet for additional warmth.

If you go with any sort of space blanket,SOL is good stuff.Reflectix is worth looking at though.

06-17-2019, 10:51
Note that in building construction circles reflectix is has a reputation of making claims that are not true using test methods they dreamed up themselves.

Five Tango
06-17-2019, 11:05
Personally,I would not use and am not recommending reflectix as one's sole ground pad.That said,a piece of of it folded over makes a reasonable sit pad,back warmer,foot warmer,and a good something to put on the ground to sort out some of your gear.Leaves do not stick to it.I always have a piece of it in my pack.

06-17-2019, 16:19
For both of the above reasons, reflectix is something I use solely to augment my real pad/insulation! It's cheap, and also makes nice cozies for your pot & cup.

06-17-2019, 22:03
I usually have some Reflectix left over from handyman insulation projects. It's a cheap and easy way to turn a three-season pad into at least a marginal winter pad. It won't compete with an Exped Downmat XP9 at $230, but it'll get you through an occasional night on the snow for practically nothing.

06-18-2019, 20:36
I don’t do a lot of “ on the ground” winter backpacking, but lots of late fall, and a few nights in wood floor lean-tools, and unheated hut stays during winter months in the NH Whites. I invested in a Big Agnes SL Q-Core insulated air mat, and a Sea to Summit reactor bag liner. Kept me Pretty warm all around, and the Q- Core did not let ground cold through from the lean-too floors. (huts have cold vinyl covered bunks) How they would fare on packed snow? I just don’t know, and probably never will. Insulated air mat is your best bet.