Waterproof Membranes - how they work & how to care for them

GTX is an extremely thin membrane layer of expanded polytetrafluoroethylene (ePTFE) more commonly known as Teflon! The membrane has over 9 billion pores per square inch…. Giving Gore-Tex it’s waterproof, windproof and breathable characteristics.



For use in products like jackets and pants, GTX is bonded between a high performance lining and an outer fabric that has been treated with a durable water repellency (DWR).  The DWR prevents the main outer layer of the product from becoming wet – causing the water to ‘bead’ off the outer layer.


It is a common misconception that, once the DWR wears off, the jacket is no longer waterproof. DWR is the jackets first defense, it wears off fairly quickly but the waterproof membrane is the main barrier. Although water may not bead off the jacket anymore you will still be kept dry and protected by the inner membrane.

Being a waterproof barrier is not the only thing GTX is good for. Due to the porosity of GTX the body’s own tissue is able to grow through the material making it extremely useful in medical applications such as sutures, vascular grafts, heart patches, synthetic knee ligaments and as membrane implants for glaucoma surgery.

eVent is also made of ePTFE like GTX but the pores of the membrane are lined with an oleophobic and hydrophobic (oil and water hating) chemical. This allows the membrane to remain air permeable. For this reason, eVent has been tested to be almost 200% more breathable than Gore-Tex. The down side is that the membrane isn’t as protected and durable as GTX and requires much more  TLC to maintain it’s high performance.

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eVent is used a lot in waterproof compression bags; because of its amazing breathability air is able to be pushed out through the fabric making the bag as small and compact as possible while still being waterproof. These are fantastic for sleeping bags when out on a multi day hike, rafting, kayaking, really whatever pursuit you’re doing they are great!


Hydronaute is a house made membrane created by Mont. Well known for its durability and breathability. The membrane is laminated to a face fabric using innovative technology to create superior weatherproof-ness and comfort. The face fabrics that Mont use are crucial to the performance of their garments. Mont has access to some of the most advanced face fabrics on the market that provide increased abrasion resistance, tear strength and pinhole resistance. Mont Hydronaute products are durable, bombproof wet weather garments made specifically for the Australian bush.


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Waterproof membranes aside, it also comes down to the style of jacket. There are GTX cycling jackets – super thin and lightweight, not suitable for bushwalking. There are 3-layered knee length super hardy Mont jackets – not suitable for backpacking and travelling minimal. When it comes to choosing the right jacket have a good think about what it is you’re going to be using it for and find the jacket that suits the activity. You may end up with 2 or 3 different styles or decide that, instead of buying brand new for a once off trip, hiring as suitable jacket would be a better idea.


Caring for your waterproof garments:

Exposure to sweat, dirt and chemicals in sunscreen & deodorant can have a negative impact on your waterproof garment. So, to keep it performing at its best, it’s important you clean and care for it properly.

I wouldn’t recommend washing your jacket after every single use; there is damage that can be done in over-washing. Personally, I would wash mine after a multi day hike but only if I actually wore it in some pretty full on weather conditions. Maybe you just need to hang it up in the sun to air out for a little bit instead of doing a full wash.


Before washing your jacket, pants or whatever it is you’re washing, check the care instructions on the label, empty the pockets off any rubbish, lip balm, lighters… all those things that you can never find that end up in the pockets of your rain jacket :-)
Always use a specific GTX/waterproof approved liquid wash. Something like Grangers or Nikwax. Read the bottle for instructions on how much to use – usually it’s 2 capfuls for the first item and then 1 per item after that. Wash your garments on a gentle cycle with no hot water.

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Once done, hang on the line to air dry until just damp and then put it in the dryer on a low heat setting to finish off. The heat from the dryer will help to restore and prolong the DWR coating on your jacket.




At the end of the day, the technology in the different waterproof membranes is fantastic. Choose the right jacket for your adventure (or hire one!), treat it well, and you can't go wrong!