Outerwear Tech

Author: Jason Volstad

There are two components to the outerwear we use in winter sports. The outerwear must be waterproof to keep you from getting wet from the outside, and breathable to keep you from getting wet from the inside (sweat). Snowboarding is a stop-start activity so your outerwear needs to be able to keep up with you when you’re working hard, and not let you down on the chairlift. It needs to keep you comfortable over a wide range of conditions, sometimes in the same day!

The ubiquitous yellow raincoat is most people’s first experience with waterproof outerwear. Rainwear is 100% waterproof but not breathable at all; this makes it unsuitable for sub zero temperatures, as you can get hypothermia if you sweat in it. It takes a lot more heat and energy to keep a wet body warm.

This old style can still be found in use on ships and for summer rainwear, but is being replaced by more high tech garments. Rainwear generally has a rubber coating or is made out of rubber; waterproof/breathable outerwear is more complicated.

If we were to take apart a snowboard jacket or pants we would find an outer shell of nylon, then on the underside of that there would be a thin layer attached to the nylon, and then inside that there may be another layer attached to it, or a free hanging lining of mesh or fleece or a combination of both. Sometime a smooth layer is used instead of a mesh/fleece lining, and sometimes some form of insulation is put between the inner lining and the outer layer.

The outer nylon layer of the jacket or pants is usually coated with a DWR coating, which stands for ‘durable water resistant’ coating. This is a very thin clear layer that repels water. This is what makes water bead up and roll off your jacket and aids in keeping you dry, but is not responsible for the majority of the waterproofing; it is only the front line of defense. This coating wears off over time and should be replenished using any number of products such as Nikwax or Revive-X.

The key to making a garment waterproof/breathable is in the layer used underneath the outer layer of nylon (remember, the DWR is on the outside of the nylon). This layer consists of a very thin laminate (sheet) or coating that has billions of holes in it. These holes are too small for a water droplet to come through, but are big enough to let water vapor (sweat) go through it.

The laminate or coating will have a waterproof rating and a breathability rating. The first number listed is the waterproof rating. This is usually measured with a column test. Basically they see how tall of a column of water the waterproof/breathable layer will hold before it starts leaking. Remember, the holes in the waterproof/breathable are smaller than a droplet of water, but with enough pressure some water can come through. The results of the test are usually expressed in millimeters of water and will be listed as 20,000 or 20K, or 10,000 or 10K (you get the picture). 

The breathability is measured by how much water vapor in grams can pass through a square meter of waterproof/breathable fabric in a 24 hour period. The waterproof/breathable fabric is suspended above a water source which is then heated to form water vapor. The amount of water is weighed before and after the 24 hour period, and then the rating is expressed in grams per square meter per 24 hours (gm/m2/24hr or shortened to just ‘gms’)

These ratings are determined by the manufacturer by using a couple of different tests and should be taken with a grain of salt. The higher the rating the better the performance is in general. However the ratings are for the laminate or coating only and may not reflect the real world performance of the garment. The type of nylon used, the thickness, and the texture of it will likely affect performance. A thicker, rougher nylon may tend to hold water or snow on the outside which can affect breathability. A thin slick nylon that sheds snow and rain better may be more breathable than thicker heavy canvas nylon. The construction of the garment affects the breathability as well. Wherever there is a seam it will be taped so that water doesn’t leak through the holes; seam tape is generally not breathable. A complicated jacket with lots of pockets and flair may not breathe as well as a simpler jacket.

There are generally two types of construction. The most common type is referred to as ‘2 Layer’ or 2L. This type of outerwear has a lining of mesh, mesh and fleece, fleece, or a satin type of liner. The other type of construction is called ‘3 Layer’ or 3L. This type has an inner layer that is bonded directly to the waterproof/breathable layer and nylon layer, making the jacket appear as one thin layer. These jackets are less common and usually more expensive as they are generally highly waterproof and more expensive to make.

It all sounds very complicated but there is good news. Today’s outerwear performs better than ever and with some research and thoughtful consideration it’s likely that what you purchase will serve you well. Follow the care instructions on your outerwear’s hang tags and it should last you many years.

If you have any questions, ask one of our shop staff on the Boardworld Forums.