mavic + womens jacket


If you’re heading to the mountains waterproof gear is essential. Whether you’re playing in the snow, hiking, or climbing, outdoor weather can be unpredictable, especially in the mountains. 

Waterproof and breathable fabrics will keep you dry and comfortable, which we can all agree is pretty important in outdoor sports. So, what is waterproofing, and what do the numbers really mean?


We give you the lowdown on everything you need to know about waterproofing and breathability.  

Waterproof Rating

You’ll be able to tell the waterproofing rating from the number attached to the label; the higher the number, the more waterproof the fabric. 


The number indicates how waterproof a fabric is, measured in millimetres. Using the first rating 5,000mm as an example, if you were to put a square tube with inner dimensions of 1” x 1” over the fabric, you could fill it with water to a height of 5,000 mm before water would begin to leak through the fabric. So, the higher the number, the more waterproof the fabric.


You’ll often see another number alongside the waterproofing number, expressed in grams. This refers to how breathable the fabric is, as tested how many grams of water vapour can pass through a square meter (m2) of the fabric from the inside to the outside in a 24-hour period. In the case of a 5,000g fabric, this would be 5,000 grams. The larger the number, the more breathable the fabric. 


Whilst the above test is the most common waterproof testing many manufacturers have other testing procedures that they use as well. This means that whilst the ratings provide a  good benchmark for waterproofing different manufacturers have different rubrics and testing, so there can be some variation with waterproof fabrics. 


Although fabrics can be fully waterproof, such as rubber and wax, outwear for active sports will usually be varying degrees of water-resistant, as with enough water, wear, and pressure, it will eventually leak. 


It is important active outerwear retains an element of breathability, otherwise, you’ll keep the water out but soon be wet from your own perspiration. As a result, most outwear balances protection with breathability.  

norrona + ski jacket


Waterproof fabrics are typically made up of two or three layers: a 'face fabric', a coated membrane and a tri-coat mesh. 


The outer layer, known as ‘face fabric’ is usually made of nylon or polyester. This layer is designed to look stylish and offers protection in the form of a treated solution called DWR (durable water repellent) so it doesn’t soak up water. 


The bulk of the waterproofing is left to the membrane, which is made with Teflon (ePTFE) or Polyurethane (PU). The material is made of tiny holes too small to let water in, but large enough to allow water vapour to escape. Contamination with oil, sweat, and other chemicals can cause the membrane to lose the ability to keep out water; the membrane is protected by an ultra-thin layer of Polyurethane or other oleophobic (oil-heating) treatment. See our GORE-TEX treatment guide 


One of the most well-known membranes is GORE-TEX. It is an extremely verstaile ePTFE membrane and is used by a wide range of brands in their products. It is also rigrousuly tested, making it the gold standard of waterproofing. 


With 3-layer waterproof items, they are often bound with a tri-coat mesh to protect the membrane. That being said 2-layer fabrics are often bound with a fabric liner for added comfort and protection. 


Modern waterproof breathable fabrics have come a long way since the original GORE-TEX®; now, most are extremely waterproof at any price point, but huge gains in breathability in the past few years have redefined the market in high exertion outerwear.



Sitting alongside their waterproof and breathability ratings, these fabrics are also typically classed in layers; either 2 layer, 2.5 layer, or 3 layer, often abbreviated to L. 




This is the most commonly used construction for waterproof outerwear. Typically this construction will use the same fabrics and membranes as 3 layer but without a bonded layer on the inside, using a mesh or loose fabric lining instead.  


Although 2 layer fabrics can offer the same waterproofing rating as a 3 layer, they’re often bulkier and heavier with the looser layer inside. One of the benefits, however, is their cheaper price point. 




2.5 layer fabrics don’t have a bonded mesh lining or a separate sewn-in lining but include a very fine raised pattern screened onto the membrane to keep it off your skin. The raised pattern helps to protect the laminate from your body oils, sunscreen, bug spray, and anything else that can break down the material over time.  


Most commonly found in rain shells, this fabric can also be used for winter sports too. Like 3 layer fabrics, these can be lightweight and easily packable. 



3 layer fabrics are constructed with an outer layer, or ‘face fabric’, usually made of nylon or polyester and a ‘membrane’ that’s bonded to it; membranes are the waterproof layer.  Then, a very lightweight backing fabric is attached to the interior. It’s not loose hanging like a 2 layer and helps to improve comfort by absorbing moisture and helping transport it through the membrane and to the surface of the face fabric. The interior lining also helps protect the waterproof laminate from being dissolved by skin-borne substances.  


This is the most advanced construction offering a protective, lightweight, durable, and most importantly breathable fabric, but it comes at a price.   


mens jacket + skis


A minimum of 5,000mm is good for both skiing and snowboarding in cold but clear conditions, especially if you enjoy taking regular breaks. 5-10,000mm is ideal for those who spend long days out on the mountain, in all weather conditions; while 10-20,000mm is best for those in wetter climates or skiers and snowboarders who prefer backcountry.  



Seam sealing, or seam taping, cover the tiny holes made by sewing around zips and pockets, so they don’t leak. This process is usually done using a heat application of thin, waterproof tape. 


The alternative to sewing is welding or bonding, which attaches the pieces of fabric together using heat-activated film. Bonding can be lighter and less bulky but can become costly. 


Sewn seams tend to be a little stronger so often brands will use both methods when producing their garments. Using sewn seams around stress-bearing areas such as arms and legs, and bonded for pockets and zippers. 


Outerwear often comes with different levels of taping from ‘fully taped’ to ‘critically taped’. With fully taped garments every seam has been made waterproof, whereas critically taped garments usually only have ‘high exposure’ areas taped such as the neck, shoulders, and chest.