Anyone who loves the outdoors is incredibly optimistic about the weather, especially when they are trying to convince a less outdoorsy friend that they should come hiking.
“Come on”, they’ll say. “You have to join us, it’s amazing in the Cathedral Ranges. When the sun comes out, you can see for miles in every direction when you get to the top of South Jawbone Peak…”
Anyone who loves the outdoors knows that they need to be prepared for rain — we just don’t like to talk about it too much. It’s bad luck.
Luckily there is an enormous variety of waterproof breathable clothing and outdoor gear out there to keep you warm and dry when the promise of fine weather doesn’t ring true.
But what are products like GORE-TEX®, eVent®, and HyVent® actually promising us? How do these types of fabrics even work? Can a jacket really be waterproof?
We’ve asked these questions ourselves and found some answers. In our waterproof breathable clothing buyer's guide, we'll take a closer look at fabric technologies to help you make the right choice the next time you’re looking for gear to keep you warm and dry on your outdoor adventures.
What are waterproof-breathable fabric manufacturers promising?
The term ‘waterproof’ sounds like a pretty impressive promise, one that many fabric manufacturers make all the time. Unfortunately, the term is slightly misleading, there aren’t any materials out there today that are 100% waterproof and breathable at the same time; today’s technologies just aren’t capable of doing both perfectly. But, that doesn’t mean that what fabric manufacturers have achieved is anything short of amazing.
There are actually two types of waterproof fabrics out there: non-breathable waterproof fabrics and waterproof breathable fabrics.
Remember Paddington Bear in his yellow raincoat? Paddington stayed happily dry in his non-breathable waterproof, PVC-coated-plastic gown, but if he were to go skiing, he’d soon be wet from the inside out as he started to sweat profusely. A more active Paddington would’ve needed gear made from waterproof breathable fabric: the stuff that outdoor gear is typically made from.
Jackets, pants, gloves, and shoes that you see on the market boasting 100% waterproof breathable fabrics are actually capable of differing levels of water resistance.
But that’s a good thing because you need your garment to breathe — just ask Paddington after a run…
How do waterproof breathability ratings work?
A waterproof breathable jacket's overall effectiveness is represented by two numbers usually separated by a forward slash, e.g. 15,000/15,000. The first number represents the garments waterproof rating in millimetres/24 hours (or in the case of some brands, in psi). This number tells you the amount of rainfall the material can withstand over a 24 hour period before letting water through. If a garment is rated to 15,000mm, this means that it can withstand 15,000mm of rainfall in a single day before water will get through.
“What does the second number mean?” I hear you ask. The second number listed represents the garment’s breathability in g/m² over a 24 hour period. This is where we need to clarify what ‘breathability’ actually means when we are talking about breathable fabric.
How important is a garment's breathability rating?
Just like the term ‘waterproof’, breathability is a bit misleading as well. Many of us assume that a garment's breathability rating is representative of the amount of air that the fabric lets through. In the fabric world, however, breathability refers to the amount of water vapour that will escape into the outside environment over a 24 hour period. Breathability is all about sweat.
Outdoor pursuits are hard work, so adventurers, explorers, and athletes require clothing that not only protects them from rain, snow and wind, but that allows their sweat to evaporate and escape their body. If it doesn’t, it will collect on the skin causing them to get wet over time, and eventually, cold.
Modern waterproof breathable materials are designed to keep you warm and dry, even when it looks like the end of the world out there.
Check out this video by Polartec for more info:
How do manufacturers test a garment's waterproofness?
Well, different manufacturers have different methods, but companies like GORE-TEX®, for example, use sophisticated testing facilities that are capable of simulating rain conditions of varying intensities to test a garment’s waterproof design.
What is the difference between 5,000/5,000 and 10,000/15,000 rated garments?
Let’s look at these examples to better understand their capabilities.
A jacket rated 5,000/5,000 is suitable for hiking or running, or even cycling in light rain. Jackets constructed from waterproof breathable materials of this rating are designed to withstand light rain, not really suited to skiing or snowboarding. You might even use this jacket on a day to day basis going from home to work.
The second example has a waterproof rating of 10,000mm. This means it is suitable for skiing or snowboarding in reasonably fine conditions but won’t hold up if subjected to the pressures of heavy wind and rain for very long. This garment's breathability rating is quite high, making it a good choice for someone who works hard or perhaps perspires a lot during physical activity.
The information below should help you understand the waterproofness of different garments out there on the market.
Keep in mind that even garments rated to 20,000/20,000 plus won’t protect you in a downpour forever.
How do materials like GORE-TEX® Pro and eVent® DVlite work?
There are many different ways that waterproof breathable materials are constructed, but usually, a layer called a waterproof membrane is responsible for most of the heavy lifting.
Waterproof membranes are made of synthetic materials that are dotted with millions of tiny holes per square inch. GORE-TEX® fabrics boast an impressive 9 billion tiny holes per square inch of material!
But wouldn’t those holes just let water through?
Over time, yes, but they are the key to the garment's breathability. Water vapour created when you sweat is allowed to escape over time, hence the term waterproof breathable membrane.
What is DWR Coating?
Most fabric manufacturers will add a durable water repellent coating to their materials. This coating is what forces rain to bead on the surface of your jacket and roll off, greatly increasing its waterproofness and breathability too.
How do clothing manufacturers use these materials to make waterproof garments?
Most fabric manufacturers are very strict on clothing manufacturers, only allowing a garment to carry their seal if they have passed the relevant tests.
And it’s not enough to use waterproof breathable materials, a garment must be put together the right way too. One of the biggest challenges is seam construction.
Seam construction is where a lot of garments are let down. If you are looking for a garment with optimal waterproofing, look for fully-sealed seams. This means that seams at every point on the jacket are either taped or sealed with waterproof material to prevent water seeping through. On some garments, seams along the upper body only are sealed, which still offers a good protection, however, the garment will likely have a lower waterproof rating.
Garments Under Pressure
You might have noticed when you remove your pack that the fabric under the straps is wet before the areas subjected to the most rain.
Why is this?
There are many factors that can contribute to the slow advance of water through the outer layers of your waterproof breathable gear. Wearing a backpack puts pressure on the fabric at any point it touches reducing the waterproof membranes effectiveness at repelling water droplets.
Waterproof Breathable Fabric Care & Maintenance
Your gear is subjected to pressure not only from the weather and pack weight but from the way you treat it as well.
If you’ve noticed that your jacket is starting to let a lot of water through, you might need to give it a clean. DWR coatings can wear out over time as a garment gets dirty and oils from your skin start to break them down. Check the manufacturers cleaning instructions: sometimes all it takes is a good wash, and even a gentle iron to renew the DWR coating on a piece of clothing.
Range of Waterproof Breathable Gear Available
Waterproof breathable fabrics are so versatile: they can be applied to jackets, pants, shoes, gloves, hats, tents, backpacks, dry bags – pretty much anything you can think of that you might need to stay dry on your adventures.
Now that you know a bit more about how they work, and the level of waterproofness and breathability to look for in your future gear, check out the full range of high-performance outdoor gear available at Outdoria.