How do waterproofs breathe?
The human body naturally releases sweat as a vapour, when this vapour meets a temperature greatly different from the one it was created in it condenses into liquid or indeed ice. Sweat in vapour form can pass through the microscopic pores in the waterproof fabric. Rain in droplet form is repelled from the outside.
Dry on the inside?
If you wear absorbent layers under the outer layer, the breathable performance of the outer fabric is rendered relatively useless as the vapour is trapped in the inner layers before the “breathing“ process can commence.
Fabrics like cotton (and a lesser extent silk) are NOT recommended for cold and wet weather layering systems. In sub zero temperatures cotton will soak up the sweat vapour which then condenses if you stop exercising; the damp cotton then cools very quickly and drives your core body temperature down.
What should I wear as a First Layer?
Treated polyester fabrics, including base layers (thermals) and fleece plus certain natural fibres e.g. merino wool are all superb at allowing sweat vapour transmission ensuring the vapour is transmitted to the outside before the cooling process can commence.
Traditionally the man made base layer fibres did “smell” but now most base layers have an anti-odour treatment and indeed some top of the range items now have a silver yarn within the weave of the fabric that stops the build up of ammonias that cause the smell. From personal experience when skiing the Berghaus X-static base layer was fantastic, worn for the whole week (sorry but true!) there were no odour problems.
The Layering Principle – Base Layer/Mid Layer/Waterproof
Use a wicking base layer – treated polyester fabrics potentially with silver yarn for a base layer, move on to a mid layer once again not cotton based, polyester fleeces are great and offer different weights according to temperature extremes, then a waterproof breathable outer layer. Generally the more expensive waterproofs are more breathable and therefore less prone to temperature build when exercising and wetting out when exercise is stopped the “boil in a bag syndrome.”
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All outdoor activities are potentially dangerous. These article's offer guidelines only, every effort has been made to ensure the accuracy of the information, no responsibility can be accepted for any errors or omissions.
If the reader follows any of the advice given then they accept personal responsibility for their actions. North North East LTD.