Here is my setup on thanksgiving night.

Black Diamond Lighthouse tent sitting on a Tyvek groundsheet
Ridge rest(at least 8 years old)
WM Ultralite
Sleeping in BPL merino top, patagonia R1 hoody, balaclava on my head, capilene bottoms and heavy wool socks on my feet

Here are the conditions:
27-29 degree very clear night camped near a stream in a gulley (Cold spring hollow on the rip rap trail in Shenandoah NP). Katabatic air currents could of been at play.

I did not expect to be cold using this setup, to the contrary I expected to be quite warm and to have to remove layers. What happened instead is that I woke up very cold and shivering several times in the night with very cold spots under me wherever my body was in contact with the pad. There also seemed to be moisture condensating on the top of the ridgerest below the sleeping bag.

Ground was not frozen where we were camped. I suspect the ridgerest was just not providing enough insulation. Do they do this over time. Does it make sense that I could feel this cold because of inadequate insulation? I've used this pad for a number of years and have never experience this before. But it did happen on another trip recently with a synthetic bag. So I am beginning to suspect the ridge rest has lost some of it's R value???

My girlfriend sleeping on a thermarest with a BMW torsolite for added insulation slept like a baby. It was her first backpacking trip so I made sure she was comfy...she was wondering why I did not manage to stay warm however.

If this pad is not adequate in these conditions the next question is what is the best replacement for the fall/spring colder shoulder seasons when I do not want to lug two pads for myself and I'm not camping on snow. But I need adequate insulation.

MEC yellow evazote?

Any insight into what my problem might be and suggestions for fixing it would be most appreciated

Edited by drown on 11/29/2008 17:47:27 MST.

Definitely sounds like the pad was not good enough. Seems like you had plenty of insulation on top. How about carrying a torso length piece of gossamer gear thinlite to beef up the R value. A torso length piece would weigh very little, not be too bulky, and you should only need it below 30 degrees I would have thought.

Near a stream, in a gully. Sure the extra humidity didn't make you colder? I've had that happen in warmer weather.

My guess is that two factors were involved :
1)The Ridge rest is not really ideal for below freezing temperatures
2) as Joe suggested, high humidity contributed to make you feel cold

Recently I spend a night in a very humid spot, my PO Max Thermo that has kept me warm around 40f felt cold at around 55f

Franco

That ridgerest probably wasn't adequete when new, much less after 8 years.

It could also have to do with how much you ate/drank that day.

Your pad was not thick enough, consider adding a supplement like an emergency blanket underneath your foam pad, & also consider adding a torso length pad, then you should be good to go.

Plenty of calories before bed. I don't think this was the issue.

Also it was probably humid, but not that humid the ultralite is rated to 20F...and I was in a tent. I can image that being more of an issue under a tarp...but this is a fully enclosed tent. With a dry sleeping bag and dry clothes.

Is a ridge rest alone truly inadequate below 40F? And what is the lifespan of one. Does foam break down and lose its insulation capability after a certain amount of time. I can see if it's left out in the sun...

I'd say a ridgerest is going to be pretty flat after about 80-100 nights or so.
I believe the R value is 2.6, which isn't enough for me. Around freezing, I use the RR Deluxe, which is 3.2.
Humidity should actually be greater in your tent than it would have been in a tarp.

> Does foam break down and lose its insulation capability after a certain amount of time

I shouldn't think it is a problem of the foam "breaking down". More like becoming flatter/compressed. The insulating value of the pad is directly proportional to the thickness of the pad, so when it gets squashed over time I would expect the insulating value to decrease. I wouldn't expect the increased density of the material to compensate for the reduced thickness. (Disclaimer: I may not actually know what I'm talking about... Richard Nisley would have the correct answer though.)

A mate of mine has just returned from a tent testing trip (in China) . For a few nights the temperature was down to about 10f, his comment was the his North Face Ibex bag was warm but his pad ( an inflatable without insulation) felt like an "ice sheet" the result was that he woke up several times shivering. He failed to consider conduction heat loss. But this has been my point of contention for some time, that people think that because they have a "warm" sleeping bag, any mat that they can tolerate (as in soft/thick enough) is good enough.
Franco

Edited by Franco on 11/29/2008 23:07:04 MST.

>Also it was probably humid, but not that humid

You would probably be very surprised how humid it can get in an enclosed tent on a cold night with two people breathing and perspiring all night!!!

You might consider:

1.Buying a new pad, closed cell foam gets flat after a few years.
2.Consider adding a torso sized pad to your sleep system(on top of your main pad).
3.Consider wearing more clothing to bed.
4.Make sure your tent will "breathe" well enough for the
temperature and humidity level you will be facing.
5.Make sure to eat and drink enough hot food before bed.
6.Get your blood flowing by doing some excersises before bed.

Edited by edude on 12/08/2008 18:15:03 MST.

> 6.Get your blood flowing by doing some excersises before bed

I believe that's how the kitten in Evan's profile pic keeps warm.

Winter camping means the sun goes down early and comes up late. You may spend 12 hours at a time in the sleeping bag.

Get a decadent pad. I camp for 10 days at a time in the northern rockies. I have a negative 35 Feathered Friends bag (huge!) and I sleep on a evazote WINTER with a full-lenght Therma-rest PRO-lite pad.

Yes, I know, it's all heavy - but - I can save a lot of time dealing with a shelter. by sleeping out under the stars at 20 below zero.

The point is it's winter, and sleeping is very important. So I make sure I'm warm. If I wanted to save weight, I would keep my pad set-up and use a lighter sleeping bag. The pad (system) is MORE important than the SLEEPING bag.

Also - Your girlfriend was with you? Spooning is a fantastic technique! It works!

And - All the other advice in this thread is excellent.

I wondered when someone was going to bring up shared bodily warmth.....

Just putting in another vote for the gg thinlite it's amazing the warmth this little pad can add to any sleep system. Also piece of mind, you will never trust that ridgerest again my friend. Next time you hike with it if it's chilly at all you'll wonder all day if it's gonna be a another long night.