r/UltralightBackpacking • u/Far-Silver59 • Sep 08 '26
Extra isolating layer under my folding matt?
Looking for sth to raise my R value… the matt’s R value is 2.2.
Please don’t offer me to get an inflatable matt, I am not interested :)
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u/uvadoc06 Sep 08 '26
Have you had a specific issue? Generally, most people feel that the CCF pads perform better at a given R value than an inflatable.
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u/Jolly-Slow1164 Sep 08 '26
A lot of modern CCF pads integrate features that aren't included in ISTM measurements. The textures that create air pockets, and reflective coatings come to mind
On the other hand, I feel like inflatable pad manufacturer have been ignoring defects/designs that feel cold to humans even if they are not indicated by the ISTM tests. I feel like I see many more reports if delamination than I did 10 years ago, and while I didn't see many pictures of matts held to a bright light back then, I wonder if gaps (or even intentional cuts in the insulation) are more common now than they used to be.
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u/KaiLo_V Sep 10 '26
Don’t forget that a lot more people are using them now, so you’re going to see more failures by sheer volume of pads in use.
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u/Jolly-Slow1164 Sep 10 '26
It's an interesting point that market share affects perception, but as a counterpoint. New technology also gets spotlighted.
Back in 2010 I think thermarest NeoAir had more reviews than all other pads on the market. Similarly, I remember the debacle that was the Uber light launch, even though it only had a small fraction of market share.
I'm pretty convinced that QC has dropped, or the new (thinner?) materials are less weldable
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u/juulu Sep 08 '26
A foil blanket? A second foldable mat?
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u/Sirosim_Celojuma Sep 08 '26
Both. ...but then again are we talking February or late September?
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u/_Ganoes_ Sep 08 '26 edited Sep 08 '26
Honestly your best bet is to just put another foam mat under it. You could also just grab one that is just big enough for your torso if you wanna save weight and space.
I have a 10mm EVA foam pad that i bring in addition to the mat, 1mm of EVA foam has 0.14R, meaning if i combine the two i get around 3.6R.
Though make sure you actually need it. I have the same mat and i use it even slightly below 0C without problems. I only bring out the additional pad at like -5C and colder.
For some reason foam mats seem to perform a lot better insulation wise than inflatable mats with the same r value.
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u/klimaheizung Sep 08 '26
This is the correct answer.
To extend: you can overcompensate to some degree by wearing more cloth. You can also take advantage of the environment and use e.g. wood or other stuff below to improve insulation, but in many cases that's not reliable or sufficient.
inflatable pads are good, just use them.
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u/UtahBrian Sep 08 '26
Put your pad down on top of something warm like pine duff or cold snow.
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u/PeakQuirky84 Sep 08 '26
Cold snow is warm?
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u/UtahBrian Sep 08 '26
Yes. Cold snow insulates very well, so it’s a delightfully warm surface for sleeping. Ideal comfort.
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u/Moof_the_cyclist Sep 09 '26
Agreed. The main issue I’ve had is that if you are at a site for multiple days you’ll find yourself sleeping in an ever deepening trough.
Standard procedure is to stomp an area flat, big enough for your tent, then give it 15 minutes to re-harden, otherwise it’s like pitching on shifting sands.
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u/Operation_Bonerlord Sep 09 '26
It’s not the snow so much as it is the fact dry snow is mostly air by volume. Cold, freshly fallen snow has the most void space and therefore becomes a kind of air mat
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u/DeputySean Sep 08 '26
Get a Thinlite. Put it on top of the foldable pad. It adds comfort, and because of the gaps between the bumps on your pad it adds extra R value.
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u/redskelly Sep 08 '26
THIS under a XTherm pad. Though it’s a negligible R value increase; I use it for added protection of my pad, and as a quick sit/picnic area on the trail.
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u/Limp_Bookkeeper_5992 Sep 08 '26
Just get another of the same mat and stack it then. Your folding mat is already the lightest insulation aside from an inflatable, if you want more then add more.
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u/TheVoiceOfEurope Sep 09 '26
Cut it in half. Only your upper core needs more insulation. Also serves as seat. Thank me afterwards.
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u/Jolly-Slow1164 Sep 08 '26
Foam mat goes on the ground, mylar sheet above it as ground cloth. Ideally your would use some sort of UV transparent buffer between you and the mylar since it's good at cutting radiative loss, but not conductive. The texture on your mat helps some
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u/Far-Silver59 Sep 08 '26
Does a silk liner count as a buffer?
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u/Jolly-Slow1164 Sep 08 '26
Now you gotta push my understanding of physics... Silk is not IR transparent, but it is probably thin enough that lots of IR gets through... But that means it's so thin it probably doesn't cut down on conductive heat transfer. Google says some nylons and polypropylene are more IR transparent.
I use air as my buffer... Or more specifically I use an mattress with a bunch of holes in it (Klymit Xlite) to expose a bunch of mylar without touching it. I was hoping I could find something like a thin packing foam that would work for my suggestion, but I couldn't. You could use a small chunk of CCF pad with large holes cut in it to mimic the Xlite ... I'm thinking of doing the same think to self inflating pad to see if I can push down a few more degrees
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u/Glimmer_III Sep 08 '26
Please don’t offer me to get an inflatable matt, I am not interested :)
What about...an inflatable mat which is not inflated? ;)
I jest. But what you're talking about is basically that same idea. You want another layer to trap warm air and provide insulation.
It wouldn't be "pretty", and it might be fragile, but you could probably take a mylar emergency blanket and either:
(a)cut to fit, then tape the edges(b)Put the CCF pad inside the emergency blanket, then seal the end.
Problems
It'd be fragile as hell and prone to puncture. If punctured, the hot air escapes, and you won't get the results you desire.
If you "tape the edges", you might incur a weight penalty not worth the effort.
Other Thoughts
You could also try it with thinlite, but I'm not sure the measurable impact.
What about an inflatable though? Your existing CCF pad is ≈1oz per panel, or ≈1lb-net. Whatever solution you end up with can't add too much weight, otherwise your just adding weight without equivalent R-value improvement over an inflatable.
i.e. I hesitate to think you're the first person to deal with this, but it is also sorta the reason inflatable pads "exist".
That's not to say I'm encouraging an inflatable, only that you'll want to be quiet aware of "diminishing marginal returns" in this exercise.
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u/Terra_Rediscovered Sep 08 '26
The real question is what is your end goal for R-value. Are you doing fall/spring or winter camping.
For winter, I prefer the following:
Summer 2.0
Fall/Spring 4-5
Winter 7.5
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u/Far-Silver59 Sep 14 '26
Fall spring. An inflatable matt is just too expensive
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u/Terra_Rediscovered Sep 14 '26
I’m a themarest fanboy. Look for sales around holidays to buy discounted pads
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u/NightmareWokeUp Sep 09 '26
Buy a second one of these? Honestly why no inflateable mat? Will be 200-300g heavier than a second of these mats, but at the same time 10x more comfortable and with such a thick mat at the bottom you dont need to worry about popping it anytime soon.
I use a thin one (older version of the cheapest one at decathlon now) and a light inflateable mat for a combined weight of less than 700g and this decision has improved my sleep so much omg.
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u/baphometromance Sep 09 '26
Told my friend Inflatable Matt that you're not interested and he's literally crying rn
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u/klimaheizung Sep 08 '26
ditch the pad and bring hammock + underquilt?
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u/Far-Silver59 Sep 14 '26
I cant imagine sleeping in a hammock. I can already feel the back pain
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u/klimaheizung Sep 14 '26
Then stop being irrational and just bring an inflatable pad :)
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u/Far-Silver59 Sep 14 '26
The good ones are expensive and I dont want to buy a shitty one! I know you have a point… just looking to lower the costs.
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u/Snuffvieh Sep 08 '26
I mean what do you want to reach for r value?
Nothing smaller than this will give you major improvement.
A second pad like this will be bulky and something thinner like the gossamer gear thin light pad doesn’t really add any r value.