Why would anyone buy a foam mat instead of a self inflating one? Self inflating mats are the in thing in camping comfort, and with the introduction of the Thermarest Neo Air some are feather weight too. The main advantage of a foam mat is that putting a hole in it doesn't damage it. It is quite easy to accidentally stand on you sleeping mat in crampons, or maybe that sort of thing on happens on student mountaineering club meets. Either way accidents happen and if your mat doesn't inflate then it wont be comfy, and more importantly it won't insulate you from whatever surface you happen to be sleeping on.
This is where foam mats come in. The ridge rest isn't just any foam mat however. One side is silvery and reflective, preventing heat loss to the ground, the other side is green. The ridge rest gets its name from the ridges which are found covering both sides of the mat. These trap air further reducing heat loss to the ground. The air cells are too small to allow effective convection and air is a good insulator. It works in roughly the same way as double glazing or cavity wall insulation.
|Ridges and the silvery coating|
It is possible to cut down foam mats too without effecting their insulating properties. I previously had a ridge rest which I cut down and used as an inbuilt bivi mat inside my rucksack.
The downside of foam mats is that they have quite a large pack size, and the ridge rest is no exception. As I have said before though you can cut them down. Why not cut it down to as small as you think you can get away with?
If you had to take one mat with you on an alpine trip I would take a foam mat, and why not the ridge rest. It has been well designed to provide maximum comfort and insulation.
I give the ridge rest 1 thumb up.
The Thermarest Ridge Rest is available from outdoorkit.co.uk in 2 different weights of foam, both with 10% off. The mat reviewed here is the more beefy "Solar" version.