| What it is | Waterproof-breathable membrane |
| Core material | Expanded PTFE (ePTFE) film |
| How it works | Pores block water, pass vapor |
| Used in | Jackets, gloves, boots |
Gore-Tex is a waterproof, windproof, and breathable membrane used in outerwear and footwear. Its core is a thin film of expanded PTFE (ePTFE) with billions of microscopic pores far smaller than a water droplet but larger than a water-vapor molecule, so it blocks rain while letting sweat vapor escape. It’s the best-known of the waterproof-breathable membranes.
How it stays dry
The membrane needs a DWR finish to keep its breathability; performance is described by a waterproof rating. A key rival is eVent.
Frequently asked questions
What is Gore-Tex?
Gore-Tex is a brand of waterproof, windproof, and breathable membrane laminated into outdoor clothing and footwear. Its functioning layer is a microporous film of expanded PTFE whose pores are too small for liquid water to pass but large enough to let perspiration vapor escape, keeping you dry from both rain and sweat.
How does Gore-Tex work?
The ePTFE membrane has about 9 billion pores per square inch, each roughly 20,000 times smaller than a water droplet but 700 times larger than a water-vapor molecule. So rain can't push through, but the warmer, higher-pressure water vapor from your body diffuses outward. A DWR finish on the outer fabric keeps the face fabric from wetting out, which preserves breathability.
What's the difference between Gore-Tex and eVent?
Both are ePTFE waterproof-breathable membranes, but they manage breathability differently: traditional Gore-Tex uses an additional protective layer (PU) over the membrane, while eVent's 'Direct Venting' lets moisture pass straight through the membrane, which many find more immediately breathable. Newer Gore-Tex variants narrow the gap.
Sources
- How GORE-TEX works — W. L. Gore & Associates
- Waterproof-breathable fabrics — The Mountaineers