Gore-Tex Explained
In brief: Gore-Tex is a waterproof, windproof and breathable membrane made from expanded PTFE (and, since 2025, an expanded polyethylene alternative). The microporous film is bonded between or behind your jacket's outer fabric and lining, blocking liquid rain while letting body-heat vapour escape. It is the benchmark most other membranes are measured against.
What Gore-Tex actually is
Gore-Tex is a thin membrane invented by W. L. Gore and Associates in 1969, when Bob Gore discovered that polytetrafluoroethylene (PTFE, the material in non-stick coatings) could be rapidly stretched into a strong, porous film. That film, expanded PTFE or ePTFE, is the heart of classic Gore-Tex. Independent descriptions of the structure put roughly nine billion pores in every square inch of membrane, each pore around twenty thousand times smaller than a water droplet but several hundred times larger than a molecule of water vapour. That size gap is the whole trick: liquid rain cannot push through, but the warm, gaseous sweat your body produces can pass out.
On its own the ePTFE film is fragile and, importantly, oil from skin and food can wet it out, so Gore laminates it to a protective layer and usually adds a hydrophilic polyurethane coating on the inside. That sandwich is what gets bonded to your outer face fabric to make the finished Gore-Tex laminate.
Waterproof and breathable at the same time
Two jobs that normally fight each other are handled together. Waterproofing is measured as a hydrostatic head, the height of a water column the fabric resists before it leaks; breathability is measured as moisture vapour transmission. Gore is unusual among brands in that it does not publish a single headline hydrostatic-head or breathability number for Gore-Tex. Third-party testing has reported figures around 28,000mm of hydrostatic head for Gore-Tex laminates, which is far above the roughly 1,500mm that the outdoor trade loosely treats as the threshold for calling something waterproof, but treat that 28,000mm as an external estimate rather than a Gore specification.
Instead of selling a number, Gore sells a guarantee. The brand's promise is that a garment carrying the Gore-Tex name will keep you dry, backed by its Guaranteed To Keep You Dry pledge. Every finished garment design is tested, including a rain-room assessment under simulated downpours, before it earns the label.
The move away from PFAS
Classic ePTFE belongs to the wider family of fluoropolymers, part of the PFAS group now under heavy regulatory and environmental scrutiny. Gore has spent years moving its consumer laminates onto a new membrane built from expanded polyethylene, ePE, which is thinner, lighter and made without the fluorinated chemistry of the original. The ePE membrane was introduced into the Gore-Tex range from 2022, expanded through 2024, and Gore has positioned it as the basis of products described as made without intentionally added PFAS. Older and some highly technical laminates may still use ePTFE, so the membrane in any given jacket depends on its model and year.
How to read a Gore-Tex garment
Gore-Tex is not one single thing. It is a family of laminates tuned for different uses, from lightweight packable shells to heavy-duty mountain armour. The face fabric bonded to the membrane changes the weight, durability and hand-feel, while the construction (two-layer, two-and-a-half-layer or three-layer) changes how the membrane is protected. When you see Gore-Tex on a label it tells you the waterproof-breathable engine inside; the specific sub-brand, such as Paclite or Pro, tells you which version of that engine you are getting.
Caring for the membrane
A Gore-Tex membrane can last for years, but the outer fabric in front of it relies on a durable water repellent (DWR) finish to stop the face soaking up water and feeling clammy. That finish wears with use and washing. Re-proofing with a wash-in or spray-on treatment, and warming the jacket in a tumble dryer or with an iron on a low setting to reactivate the DWR, restores beading and keeps breathability working. Dirty membranes breathe poorly, so washing a technical shell is maintenance, not a risk.
Gore-Tex at OD's Designer Clothing
We stock Gore-Tex pieces from brands that build for real British weather, where a membrane has to cope with hours of drizzle rather than a passing shower. If you are unsure whether a jacket uses the classic ePTFE or the newer ePE membrane, or which construction suits your use, the team can talk it through in store or over the phone before you commit.