How Gore-Tex Really Works.

Gore-Tex has become a household name. It’s something that we always look out for when buying a jacket. Those seven, hard capital letters subtly imprinted into material seem to justify an expensive price tag. But what does the extra money really get you?

Sharp End Shell Jacket 2015

The real name for what Gore-Tex is, is polytetrafluoroethylene or PTFE. It’s a plastic material that is heated and then quickly stretched, resulting in a microporous structure that is roughly 70% air. The micro pores are so small that water droplets cannot pass through them. However, the much smaller water vapour molecules you produce when you sweat can pass through the material. This is why Gore-Tex is called a breathable fabric.

But this is not the end of the construction story. The PTFE, would be damaged too easily if used alone. Modern technical jackets and pants are usually made with either three-layer or two-layer constructions.  The PTFE is bonded with a nylon or polyester sheet which protects the outside of the material from abrasion, without drastically affecting its breathability and impermeability. The outer material is also treated with a durable water repellent (DWR) coating. The DWR coating causes the droplets to “bead” off the material, allowing the water vapour to escape, and therefore keeping it breathable. In a three-layer construction the inside of the PTFE is also bonded to a similar durable material, but this usually isn’t DWR treated.

Point Five NG Pant 2016

Gore-Tex isn’t the only material of this type however. Some clothing brands, such as Mountain Hardwear, use their own PTFE materials.  There are a few rival companies, such as e-Vent, that are integrating their membrane technology into a vast range of technical clothing.

There are many jackets available right now that are classed as “waterproof” but are much more affordable. For a jacket to be classed as waterproof it must be able to hold a column of water at least 1000 mm high. This may sound like a high bar to pass but in reality a jacket that is close to this limit is far from capable of keeping you dry in a storm; for reference, the latest Gore-Tex materials can withstand a column of water around 30,000 mm high.

Front Point Jacket 2015

Gore-Tex and other waterproof materials aren’t a perfect solution though. Over time the micro-pores in the PTFE will clog up with dirt and grime and the material will lose its breathability. The material can be washed but be careful not to use standard washing agents as they will destroy the DWR coating. Repeatedly scrunching up the material and stuffing it in your bag will also damage the microporous structure.

Gore-Tex has definitely improved modern technical clothing, allowing humans to explore new locations and survive in harsher environments. With many more brands now competing with Gore-Tex, it makes sense that the technology will continue to improve. Remember, “There is no such thing as bad weather, only inappropriate clothing.”