Waterproof, GORE-TEX and eVent explained

Why can’t you wear a bin bag on the hill?

Did you know that a bin bag is waterproof? True. Not stylish, but still waterproof. It’s cheap too. We don’t sell them, but that’s okay. We don’t think you’d want one anyway. Even though water will run off it like you’re a duck, you’ll soon want a proper waterproof. Wearing a waterproof, but not breathable bin bag means you’ll probably lose 2 stone in sweat, as well as your sense of humour, and need to top up your Camelbak before you’ve even considered climbing a hill.  Our point is, for exertion, you probably need to shell out a bit more on your hardshell.

The bin bag analogy is similar to wearing a really cheap coated waterproof. Coated with a DWR (Durable water repellent) that encourages water to bead off, but also keeping moisture in, the difference between cheap and not so cheerful and more expensive but comfortable is breathability- or moisture release. Your body creates heat just by your breathing and your heart pumping. Your own physiology works so that even a bit of movement causes heat to be released. If you’re wearing the wrong clothes (like cotton, or a waterproof that doesn’t let this heat and moisture escape)- you’re going to feel wet.

The main forerunners in waterproof and breathability expertise are membrane fabrics like GORE-TEX® and eVent®.

An example of a GORE-TEX® Pro Shell, releasing heat and fending off rain.

What is GORE-TEX®?

A GORE-TEX® product is made from a bi-component membrane. This works a bit like your skin, with over 9 million microscopic pores per square inch, all 20,000 times smaller than a single bead of water. The pore size is still 700 times larger than a moisture vapour molecule which allows gas and heat to be released. A breathable oil-hating cover is also integrated into your GORE-TEX® membrane, which is olephobic (able to repel liquid, oils, cosmetics and dirt).

An example of how eVent® works to ‘let the air out’™

What is eVent®?

eVent® is a fabric designed to work as a waterproof and breathable membrane, used in a variety of outdoor garments, most commonly seen in waterproof jackets .eVent® fabrics are designed to ‘let the sweat out™’ and use a patented waterproof membrane constructed of millions of tiny pores.  From these pores, sweat vents to the outside of the fabric in one easy step, called Direct Venting™ Technology.

What are the differences between them?

The difference between eVent® and GORE-TEX® is that:

eVent avoids using a PU membrane. Whereas a GORE-TEX® jacket uses a polyurethane layer in their fabrics to absorb sweat in a two layer process, eVent® application is made to the inner layers of the garment, taking away the need for a PU layer.

eVent refer to this as Direct Venting Technology. This means that eVent® is technically more breathable, and therefore quicker to dry, than GORE-TEX®.

HOWEVER – this isn’t all good news, as eVent® may need more care than a GORE-TEX® alternative as the PU layer protects the PTFE layer from oil and grease. Chances are your eVent® jacket will need to be washed and reproofed more often than a GORE-TEX® alternative. Because of the highly breathable benefits of eVent® this is even more important than with other membranes, as it will keep your eVent® garment performing at it’s best!

Choosing the right membrane can take time and effort!

What should I choose?

The fabrics of GORE-TEX® and eVent® are both designed to fit the same purpose, to be breathable, windproof and waterproof, and both membranes do this remarkably well.  Obviously, this doesn’t make choosing between them much easier! The key point is that the differences in how the membranes are made means that some e-Vent® is generally more breathable, whereas GORE-TEX® is warmer. However it’s important to remember that because both membranes are 100% waterproof, there’s always going to be a compromise at some point on how breathable and cool you feel.

Neither GORE-TEX® nor eVent® will work like magic, keeping you completely cool against extreme heat. The best advice I can give is to choose from your budget (eVent® tends to be slightly pricier) and if you’re still pushed to make a decision, then I suggest you choose eVent® for warmer conditions, and GORE-TEX® for cooler conditions.

I hope this clears up some of the basics of waterproofing and a bit about GORE® and eVent® for some of you! If you’re still interested and want more information, click for our guide to GORE-TEX®.

Stay happy and dry!