Winter Ground Mat

6:14 p.m. on July 29, 2008 (EDT)
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I am after a ground mat for winter camping use and have been looking at either a very high quality foam mat (Mammut 1.8cm) or a Thermarest, prolite 4 or Trail lite.

Can anyone advise what would be the best for warmth/insulation from the ground?

Both are expensive and I can only afford 1.

Thankyou for any adive.


12:51 a.m. on July 30, 2008 (EDT)
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If you are camping on snow, the normal procedure is to use a double mat - a full-length (72-inch) closed cell foam (non-inflatable, with the "Blue Foam" that you can get at the big box stores being plenty adequate) plus an inflatable or a second closed cell pad. It is not necessary to spend the money on the Cascade Designs RidgeRest or ZRest, when the Blue Foam will do just as well. The inflatable can be one of the 3/4 length Thermarest Standard or, if you are not going to be out below 10F, using a 4-season tent, and using a good sleeping bag rated for at least 5 deg F lower than the temperatures you expect to encounter, you can use the light-weight Thermarest. If you are going to be out in subzero temperatures, then one of the standard thickness inflatables is appropriate. Even in places like Denali or Antarctica, I found the Blue Foam full length plus 3/4 length Thermarest standard inflatable plenty warm (using a sleeping bag appropriate to those conditions, of course, that is -40 deg, a Feathered Friends down bag).

The problem with using just an inflatable is that if it punctures (small pinhole from unknown source or valve that turns out to develop a leak), finding the leak in winter conditions is difficult at best, which leaves you without ground insulation. Having the closed cell foam as the second layer provides you with at least a little insulation from the snow or ice under you.

The thicker inflatables are designed to keep the weight down somewhat by including various types of air channels in them. Unfortunately, this does not reduce the weight by much, makes for a much thicker roll to get into or on your pack when deflated, and does not give the insulation you would expect from such a thick pad. They are somewhat more comfortable, though. Look on the company's website (or in the company fliers) to find the R-value (this is available for Thermarest and Stephenson pads, and a few others). Higher R-value means more insulating value (R means "heat resistance" by analogy with electric resistance). Speaking of Stephenson, he (and a few other companies) use down in their inflatables rather than foam. It makes for a lighter, more compressible pad with a high R-value (and a whole bunch higher price). You would still be well advised to stack the down inflatables with a closed cell foam pad, just as any inflatable.

There is a continuing debate whether to stack the closed cell foam or the inflatable on top. I have not found it to make any significant difference, but I normally put the closed cell on the bottom and the inflatable on top of it.

5:47 a.m. on July 30, 2008 (EDT)
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Thankyou for your feedback Trying to find the "R" value of a good quality foam pad seems impossible!

I like the simplicity and robustness of a foam pad, the comfort and packability of a Thermarest.

11:50 a.m. on July 30, 2008 (EDT)
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Here, for example, is a Thermarest page for the Pro 4 ("fast and light") series -

Note that they are all about R 3.2. The Pro 3 is 2.3, the Z-lite (closed cell) is 2.2. The BaseCamp regular size in the "camp and comfort" series is 6.2, with a weight of 2p12oz, compared to the weight of a Pro4 regular of 1p8oz plus Zlite at 15 ounces for a total of 2p7oz and R value of 5.4 (Blue Foam is typically more like 8 ounces for the same R value, and you could cut the weight with a Pro 4 3/4 length at 1p1oz to get an R value of about 5.4 at 1 pound 9 ounces for the combination of closed cell foam plus inflatable, 1 pound 13 ounces less - that is less than half the weight for only a slightly lesser R value).

R values add when stacking pads (just like adding series resistors in an electric circuit).

You can provide a bit more insulation under your feet with a 3/4 length inflatable by folding some of your clothes and putting them down in the foot of your sleeping bag. The 3/4 length will provide plenty of comfort for your torso, which is where you feel the comfort.

If you are sharing the tent, you should stick with the narrower pads (20 inches typically). Since many 4-season and expedition tents are 3-person, a 20-inch wide is pretty necessary to get all 3 pads in without overlap. Even 2 in a 2-person tent takes up most of the width, leaving no room for the necessities you want inside the tent if you get the wider pads (leave the packs in the vestibule or outside covered with a garbage bag).

9:16 p.m. on July 30, 2008 (EDT)
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On my winter backpacking trips I routinely encounter zero to 5 degrees and have found the Prolite 4 to be a little thin for serious winter sleeping, but for the other 3 seasons it's a great, lightweight pad.

I wouldn't bother with the double pad idea as it's too bulky and just really unnecessary. A good 1.75-2 inch thermarest is all that is needed. And as for punctures, proper packing and carrying(in a stuff sack wrapped in a poncho if lashed onto the outside of the pack), will help alot to keep the thing from leaking. All I use nowadays is the large models(25x77x1.5/2)and they work perfectly. I like the extra width. And using an extra tarp on the floor of the tent is added insurance to keep a thermy from getting poked. Plus it helps on snow/ground water with a slightly leaky tent floor(when used inside the tent).

Here's a good test of a winter pad: When fully inflated you should NOT feel your butt touching the ground when sitting up. The Prolites have a problem with this as do the Exped Downmats, so go figure. My standard winter pad is a 1.75 inch Expedition thermy, now discontinued, but to replace it I'd go with the Trail Comfort or the newer Trail Pro, etc.

3:48 a.m. on July 31, 2008 (EDT)
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I would also prefer just the 1 mat, either thick foam pad or 3.8/5cm Thermarest as space is an issue (as well as weight)

Do you know if a 1.8cm foam pad would insulate and be as warm as a 3.8/5cm Thermarest? Comfort comes second.

6:51 a.m. on July 31, 2008 (EDT)
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Having used the cheap closed-cell foam pads as well as the Thermarest Prolite 4, as well as no pad at all (???), I can tell you the foam pad does not insulate as nearly as well as the Thermarest, and for winter camping, I won't use anything less than the Thermarest-ype of pad plus the foamie. But then again, I live in Thunder Bay, where winter temps of -20 F or colder are very commmon!

What I would suggest is this: buy the cheap foamie, and borrow someone's thermarest (btw, the prolite 4 is rated for 4-season use). Try them both on your first overnight trip, to see what works for your body type (thin? already well-padded? cold sleeper? warm sleeper?) and environment (winter in Florida? in the mountains? in a tent? or snow cave?)

That way, you can make an informed choice based on YOUR particular needs and experience. And in terms of saving weight, until you know what works, don't skimp on warmth just to have a light pack, because you likely will not sleep at all if you are very cold, and may run the risk of hypothermia, too!

Good hunting!

9:19 a.m. on July 31, 2008 (EDT)
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Sound advice and I agree. I now use a variety of mats and customize mine to suit my circumstances, I have an Exped 9 Deluxe, which I love, but, is a real pita to inflate and a BAIAC large, which is easier to inflate, but, I don't like.

I have various T-rests and use a PL-4 large over a trimmed Ridgerest large plus a couple of Golite folding waffle pads under my torso. This is heavy, I know, but, I am no longer young and comfort/warmth is crucial to me.

I am looking at black EVA foam mats locally, 5/8"thick and a bit softer than most EVA I have seen. Heavy at 1.7 lbs. ea., but, two of these would be super warm for winter and bombproof. I would rather pack a really functionable sleeping roll in winter camping and save weight elsewhere, as in no GPS or other electronic toys.

11:49 a.m. on July 31, 2008 (EDT)
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Remember that the OP said "winter camping", though with the part of the country unspecified. I assumed (dangerous thing to do, of course) that the "winter" specified was real winter, with feet of snow on the ground and significantly below freezing. Comments -
Tipi said


I wouldn't bother with the double pad idea as it's too bulky and just really unnecessary.

Actually, the combination of a Blue Foam and a standard Thermarest is no more bulky than the thickest inflatables you would backpack, and the weight is less than the single thick inflatable. And in the coldest parts of the continent (such as where NLees lives and where kutenay and I often backpack in winter), the insurance of the foam plus inflatable is extremely desirable. It is amazingly easy to puncture an inflatable (never done it myself, but I have been with friends who are professional guides who have done so).

But as NLees points out, there is "winter" and there is "WINTER!". If the winter where the OP is going to be camping is mild spring conditions or with only a skiff of snow on the ground and temperatures around freezing, plus the camping is only a weekend trip, it may be worth it to take the chance on lesser insulation and possible punctures during the learning process.

Putting a footprint under the tent or a tarp inside the tent does NOT guarantee freedom from punctures of an inflatable, nor does it do anything for a valve failure, both of which I have witnessed many times, especially among the less experienced.

mckain asked


I would also prefer just the 1 mat, either thick foam pad or 3.8/5cm Thermarest as space is an issue (as well as weight)
Do you know if a 1.8cm foam pad would insulate and be as warm as a 3.8/5cm Thermarest?

Simple answer, as NLees commented and a simple look at the R-values will tell you, is no. Generally, thicker foam provides more dead air space (the actual insulation). However, many of the thicker inflatables have air channels or other open areas in an effort to cut weight and provide a softer feel. These open areas have the same problem as the old-style air mattresses (NEVER use an air mattress for camping on snow!) These enlarged areas allow convection within the pockets (the whole air mattress in the old style mattresses and "air beds"), which means lots of cooling. The closed cell foam pads and the open cell foam or down fill in inflatables restricts convection and the loss of heat.

NLees commented


I can tell you the foam pad does not insulate as nearly as well as the Thermarest, and for winter camping, I won't use anything less than the Thermarest-ype of pad plus the foamie. ... buy the cheap foamie, and borrow someone's thermarest. Try them both on your first overnight trip, to see what works

Absolutely right, and an excellent suggestion. Different people and different circumstances call for different approaches.

kutenay, having acquired a warehouse of gear over the years (illustrating one of the benefits of advanced age, while OGBO, being of more advanced age and having similarly acquired a warehouse of gear) demonstrates the peril of having so much gear that he and Barb have spent the last 5 months trying desperately to reduce the volume of "treasures") said


I now use a variety of mats and customize mine to suit my circumstances

Same here. But the OP is headed out on a first winter campout, and other folks reading this will not want (or be financially able) to acquire a whole range of pads to try out all possible combinations. kutenay (and I, along with some others who visit this site) also have more than a few winter seasons under our belts and can judge what is needed for a particular trip. So NLees' advice is the way to go - get the blue foam (it's cheap) plus borrow an inflatable from someone, try them out separately, then stacked on successive nights. See which works better for you. Since this is the start of a long winter camping career, I am assuming (bad practice, that assuming stuff) the first few trips will be perhaps a car camp and short backpacks, so carrying extra stuff won't be too burdensome.

1:18 p.m. on July 31, 2008 (EDT)
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As usual, Bill gives very wise advice and it is definitely the best option for a beginner.\

I will say, that, after using these hotshot new BA and Exped insulated air matts, I wouldn't buy another due to cost and weight. I DO consider Thermarest a sound product and good value and have my original from about 1977.

The Exped is a superb item, but, it takes SO long to inflate and one is tired and wants his tea, so, it now is only my basecamp matt.

I don't REALLY have THAT much gear, one small room full and I have given away a whack of stuff in the past couple of years. But, really good gear makes your trips, some of the best times of your life, truely enjoyable rather than exercises in brutal survival....BEEN there, done........

4:09 p.m. on July 31, 2008 (EDT)
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Thankyou again for all the feedback, It has also been my concern that larger size Thermarests have too much air and not enough foam(built for comfort I think), causing convection worse than a thinner pad making me think of a max of a 5cm Thermarest, possibly even a 3.8. Having only been winter camping a few times in Scotland, where 0c feels like -15c in most other places! I have used a prolite 3 (2.5cm) twice before and awoke with very cold thighs, where my weight (73kg) pushed through almost to the ground on the Prolite 3 (surely reducing the effectivness) of the R rating in heavy weighted parts of your body. A foam pad (over 1cm) does not seem to squash as much, so I am assuming a 1.8cm foam pad should be equal to approx a 5cm Thermarest, but it's only a guess, hence this post for people who have more experience.

7:29 p.m. on July 31, 2008 (EDT)
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Just a thought here, have any of the manufacturers experimented with, or included radiant barriers in their sleeping pads?

I have been using a foil type radiant barrier product that is used in the Green Building Industry on top of my Ridgerest.
I have no real way to measure how effective it is with all the variables I experience, and no control group, HA-HA, but it must have some effect on the performance of my bag.

11:12 p.m. on July 31, 2008 (EDT)
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Ook, mon, mckain is a Scot! I hadna realized et.

In that case, you want all the insulation you can get. Are you sure it actually gets up to 0C anywhere in Scotland, e'en in midsummer? Scotland, home of serious ice climbing! Then again, since Scots run around in midwinter in kilts, wi' nuthan unnerneath, maybe you don't need a pad or sleeping bag at all. If you woke with cold thighs on a Prolite 3, maybe you need to wear something under that kilt. (hmmmm, the brogue doesn't come through at all well in Internetease, does it?)

Seriously, though, Scotland has some really serious winter weather. And it's wet cold as well, the kind kutenay lives in, though colder than his typical winters. Plus seriously blowing winds. I think I would stay with a 5 cm inflatable at minimum.

One thing about inflatables - it is best to let them inflate as fully as possible by themselves before blowing them up to full hardness. The reason is that your breath is warm, and the air in the pad will cool and contract, leaving you with a soft pad that can lower you to the ground. If you let it inflate by itself for a while, then add some air till the pad feels hard, a while before you are ready to turn in for the night, you will probably find it is about right, or maybe needs one more small bit of air. This is on snow or glacier, of course, which will be sucking heat out of the pad, not on warmer summer ground.

One other thing for long life of the inflatable - the morning when you are going to be breaking camp, deflate the pad as soon as you get up, squeezing all that moisture-laden breath you blew into it back out of the pad. This will slow the growth of mold in the foam, which breaks down the foam eventually.

3:03 a.m. on August 1, 2008 (EDT)
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Jim Shaw swears by his down filled air mattress. Not sure what brand. I have a standard full length ThermaRest and an old Ridgerest that I use together on snow. I have used the Ridgerest on the bottom. That combo works fine for me. The blue foam pads I have used in the past are about 3/8" thick or so and the last one I bought cost about $10 at Sport Chalet, which is not a discount store. I cut it up to make a couple of sit pads, which are very handy on snow-they make a big difference if you are sitting around eating or just sitting outside your tent. I have been using a sled,so bulk really isn't an issue for me.

Here is a trip report I posted on another forum with pictures of my camp set-up.

3:51 a.m. on August 1, 2008 (EDT)
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Scotland is colder than B.C., no, it ain't! The Highlands may be a bit colder than Van. Is., the Charlottes and the Lower Mainland, but, from Hope onward, where I do my actual camping, etc., the winters are FAR more severe than in Scotland.

Where I grew up, the winter temps. will drop to -40 and the snowfall is huge, a normal winter camp would be around 10*F during the day and -10 to -15*F at night and we would be on snowshoes or "skinny skis" on 6-12 ft. of snow on average.

Further north, where I often hunt and hope to make a fortnight's trip in about two weeks, if my buddy's work schedule permits, the winter temps frequently will go much worst is -41*F on a solo winter trip and that is COLD, when you are 12 snowshoe miles from the nearest highway.

I hope to go to Scotland, my mother's family came to Canada from Argyllshire starting in the 17thC and she finally realized her lifelong dream of visiting Culloden a couple of years before she died. Now, if a guy purchased fewer new items of gear.........

12:48 p.m. on August 1, 2008 (EDT)
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Trouthunter: Therm-a-Rest has been working on just such a pad. It's called the NeoAir and includes a radiant barrier between two layers of uninsulated inflatable air cells. I'll be checking it out at OR.

1:30 p.m. on August 1, 2008 (EDT)
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kutenay, Scotland in winter *feels* colder than anyplace I've been, including BC backcountry. Maybe not temperature - after all, Denali at 17,000 ft and Antarctica on the Vinson Massif both had many days at -40 and winds in the 50-70 knot range (according to the Nova Program Deadly Ascent, which was shot while I was on Denali, we had temperatures below -50, but the lowest I measured myself was -40). But Snowden is wet cold windy. Calgary (AB, not BC) one winter did give close competition, though, as did Lake Louise. Snowden often does have temperatures in the -40 to -50 range. Great ice climbing in Scotland, though.

Actually, the coldest I have ever *felt* was in Boston. A few months after we had moved there (January timeframe), Barb and I were headed for a place on the MIT campus. We got off at the wrong MBTA stop and walked along the Charles River to where we needed to go, wearing basically our Southern California clothing, Barbara wearing a skirt (remember when women wore dresses and skirts?) and me in thin pants, both with sweaters and a wind shell. The wind off the Charles in January can really suck the heat out. We found a phone booth (remember those?) and huddled out of the wind for a few minutes, then made a dash for the building we were headed for. By the time we were there, our legs were numb, and as they warmed up once we got indoors, it felt like we were recovering from massive doses of Novocaine. I have never been even close to feeling that cold in the backcountry or on high mountains. The difference, of course, was proper clothing.

8:59 p.m. on August 1, 2008 (EDT)
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I don't doubt that it FEELS cold, much as it does on the B.C. coast in winter; this is due to the winds and wetness and very similar topography. The feeling may also have to do with the "native" mode of dress and, should one emulate the locals in this respect, one should ALSO partake of "usequbaugh" or, "the water of life" as it is the traditional "antifreeze" and tends to make one ignore the cold.............

9:24 p.m. on August 1, 2008 (EDT)
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Single malt, of course.

1:30 a.m. on August 2, 2008 (EDT)
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Temperatures in Scotland during the winter range usually -10c to 0, nothing extreme and warming every year but it does feel a lot colder due to the dampness (humidity?) in the air. In fact the coldest days for me (hillwalking) have always been in the summer, maybe 1c and pouring with wind driven rain. After a few years hillwalking, I have still have find a waterproof that works in these conditions

And a single malt does give you a nice glow inside, even it it does lower your temperature...

5:04 a.m. on August 3, 2008 (EDT)
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It doesn't seem to get very cold there, considering the latitude; the coldest temp. recorded, I understand, is about -27*C, which is actually pretty mild, by BC standards.

An interesting aside, is that the Scots largely built Canada, most real Canadians have at least some Scottish blood and they are very strongly represented here in BC. It seems that the climate, topography and beautiful, but harsh and dangerous environment of B.C. appealed most to three groups, in the early days, Scots, Scandanavians and Germans from Bavaria and Wuerttemburg.

I attribute this to the very similar mountains, long, narrow, deep lakes and opportunities for hunting and fishing and so we are largely descended from these peoples, although different groups came later.

I should not admit this, as my mother's name was McCallum, but, I avoid Scotch totally, it makes me hear bagpipes in my head..........

10:53 a.m. on August 4, 2008 (EDT)
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For reasons I don't understand, I like bagpipe music. Oddly enough my relatives hail from Germany so this makes no sense whatsoever.

1:54 p.m. on August 4, 2008 (EDT)
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Reason Scotland (and much of Norway) is warmer than North America at the same latitude (or other way around - North America is colder than northern Europe at the same latitude) is because of the Gulf Stream. The Gulf Stream carries warm water north off the North American Continental Shelf, up through Iceland/Ireland gap and wraps around Scotland into the North Sea. This makes Ireland, Scotland, and the coast of Norway relatively warm (though Scotland can have some brutal cold in the hills sometimes). This warm water under the cold Arctic air is the reason the North Sea has some really brutal storms. Same general idea as Tornado Alley in the Midwest - warm moist Gulf air moving north encountering cold dry Arctic air moving south mix right through the middle of North America.

The Labrador Current Comes down from the Arctic Ocean past Baffin and Labrador, around Nova Scotia. Because of the shifting of the two currents and the air, New England can have some wild weather as well - Nor'Easters, the "Montreal Express" (makes Boston realllyy cold sometimes, followed in a day or so by warm temperatures - Boston is one of those places where, sometimes literally, "if you don't like the weather, just wait 5 minutes").

I think that -27C you mention was Glasgow, wasn't it?

7:13 p.m. on August 4, 2008 (EDT)
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No, it was in the Grampian Mountains, at Braemar and the coldest was about -17*F, which is just nice hiking weather. As to being wet, the West Highlands receives much less thn western B.C. does, but, it still is not "dry".

As it happens, the bagpipes were brought to Scotland and Ireland by the Celtic peoples who CAME FROM what is now Wuerttemburg and Bavaria in Germany, crossing the Rhine River about 500 BC and spreading into parts of Europe, such as the northern Iberian Penninsula, where they became the Basques and into the British Isles. Germans play bagpipes along with other instruments and, like so much Celtic culture, they appear to have come from the classic Grecian civilization to the south-east....a rather positive influence, IMHO.

I LOVE the pipes and we have a worldclass pipe band at Simon Fraser University here.

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