What is Gore-Tex? Waterproof ratings, 10,000 vs 20,000 mm, explained
Gore-Tex is the best-known name in waterproof clothing, so it is often used as shorthand for "waterproof membrane". It is in fact one brand of membrane among many. To choose a ski jacket well, you need to know what a membrane does, what the millimetre rating measures and where jackets really let water in. Here is each in turn.
For transparency: TITTALLON does not use GORE-TEX. Our jackets use fabrics we develop ourselves, mainly PHYLEX and WARMFLEX. We explain Gore-Tex here because it is the reference point most skiers know.
What is Gore-Tex?
GORE-TEX is a waterproof, breathable membrane made by W. L. Gore & Associates. A membrane is a very thin film laminated to the inside of a jacket's outer fabric. Its pores are far too small for liquid water to pass through, but large enough for water vapour (your sweat) to escape. Gore states that its membrane has nine billion pores per square inch, each 20,000 times smaller than a water droplet (gore-tex.com).
For decades that membrane was made of expanded PTFE (ePTFE). Gore has since introduced a new expanded polyethylene (ePE) membrane, which it describes as thinner, lighter and made without intentionally added PFAS (gore-tex.com, new products).
Gore-Tex is one approach. Many brands build their own membranes or laminated fabrics. What protects you is never the label alone. It is the combination of membrane, construction (2 or 3 layers), seam sealing and zips.
What is a waterproof rating? Hydrostatic head in mm
The millimetre figure comes from the hydrostatic head test. It measures the pressure of water a fabric withstands before it leaks. A fabric rated 10,000 mm resists the pressure of a 10-metre column of water (Ridestore Magazine). The figure is a lab comparison, not a promise that you could sit in 10 metres of water.
Gore does not usually publish a single mm figure for its laminates. Some retailers quote around 28,000 mm for GORE-TEX products (Ridestore Magazine).
10,000 vs 20,000 mm: how much do you need?
| Waterproof rating | Typical use (industry guidance) |
|---|---|
| Up to 5,000 mm | Dry snow and fair days; little exposure to wet snow |
| 10,000 mm | Resort days with light snowfall; dry climates |
| 15,000 mm | Regular skiing in variable snow, long days out |
| 20,000 mm and above | Wet snow, storms, frequent skiing, backcountry |
Ranges based on the buying guides of Snow+Rock and Powder7. Above 20,000 mm the practical gain gets smaller, and ratings fall with wear. A higher rating does not make a jacket warmer either: warmth comes from insulation and layers.
Breathability: g/m²/24h, RET and test standards
The second number shows how many grams of water vapour pass through one square metre of fabric in 24 hours. Higher is more breathable. Around 10,000 to 20,000 g/m²/24h suits most skiers; touring and very active skiing benefit from more.
Some makers publish RET instead, a measure of resistance to vapour: there, lower is better. The bigger trap is the test method. The same fabric can return very different figures under JIS (Japan), ASTM (USA) or ISO standards (Snow+Rock). Compare jackets only when the method matches. Several TITTALLON product pages state JIS for that reason. The same logic applies below the waist: a jacket and pant should share their ratings, as we explain in how to match a women's ski set.
2 layers, 2.5 layers or 3 layers
- 2L (two-layer): outer fabric with membrane, plus a separate hanging lining. Comfortable, takes insulation easily, standard for piste jackets.
- 2.5L: a membrane with a printed protective coating instead of a full lining. Light and packable; more common in rain jackets than in ski wear.
- 3L (three-layer): outer fabric, membrane and inner fabric bonded into one. More durable and usually more breathable. The base of most ski shell jackets.
Our own membranes: PHYLEX, WARMFLEX and 3L shells
PHYLEX is a fabric developed by TITTALLON. It aims to combine the comfort of a softshell with the protection of a hardshell. Elastane is woven into the nylon yarns for four-way stretch. WARMFLEX is our knitted outerwear fabric: very stretchy, light and soft, used across the Cloud line. Here is what each delivers in the current range, product by product.
| Fabric | Build | Waterproof | Breathability | Example |
|---|---|---|---|---|
| PHYLEX 3.0 (88% PA / 12% EA) | 2L, insulated | 20,000 mm | 20,000 g/m²/24h | Vista Tech 2L Women |
| PHYLEX 3.0 (84% PA / 16% EA) | 2L, insulated | 20,000 mm (JIS) | 20,000 g/m²/24h | Apex Tech 2L Women |
| PHYLEX 2.0 | 2L, insulated | 20,000 mm | 20,000 g/m²/24h | Alpine 2L Women |
| PHYLEX 3L (88% PA / 12% EA) | 3L shell, fully taped seams | 10,000 mm | 10,000 g/m²/24h | Element Active 3L |
| VERSA Omni Hard Shell (70% PA / 27% cotton / 3% EA) | 3L shell, full-body sealing | 20,000 mm (JIS) | 20,000 g/m²/24h | Versa 3L Men · York 3L Women |
| WARMFLEX / softshell (82% PA / 18% EA) | 2L, insulated | 5,000 mm | 5,000–10,000 g/m²/24h | Cloud Pulse 2L · Cloud Active 2L |
The lesson of the table: the fabric name is not the rating. Even within one family, figures vary by model. Always read the numbers on the product page.
Taped seams and zips: where ski jackets really leak
A fabric rated 20,000 mm still lets water in if the seams are open. Every stitch is a hole. Look for:
- Taped or sealed seams. "Fully taped" means every seam, not just the shoulders. The Element Active 3L is fully taped; the Versa 3L and York 3L use a full-body sealing process; the Cloud Pulse 2L tapes all seams against wind.
- Waterproof zips. YKK or IDEAL waterproof zips, or a storm flap over a standard zip.
- Hood, cuffs and snow skirt. Snow enters at the edges more often than through the fabric.
- A durable water-repellent finish (DWR). It makes water bead on the surface so the membrane can breathe. It wears off: washing and reproofing as the care label says brings it back.
How to choose a waterproof ski jacket, without the label
- Start with your snow. Wet spring snow or storms call for 20,000 mm; dry, cold resorts are fine with less.
- Match breathability to effort. Touring and fast skiing need more.
- Check the build: 3L shell for layering and touring, 2L insulated for warmth on the piste.
- Check seams and zips before the headline number.
Browse women's ski jackets, men's ski jackets, the wider ski collection or our snowboard collection, and compare the ratings on each page. For a curated pick, see our edit of the best women's ski jackets.
Gore-Tex and waterproof ratings: frequently asked questions
What is Gore-Tex made of?
Gore-Tex was long made of expanded PTFE (ePTFE). Gore now also uses an expanded polyethylene (ePE) membrane that it describes as made without intentionally added PFAS.
Is 10,000 mm waterproof enough for skiing?
For occasional resort skiing in dry snow, usually yes. For wet snow, storms or frequent skiing, 20,000 mm gives a wider margin. Taped seams and waterproof zips matter as much as the number.
Do TITTALLON jackets use Gore-Tex?
No. TITTALLON uses fabrics it develops itself, such as PHYLEX and WARMFLEX. Each product page lists its own waterproof and breathability ratings.
What is the difference between a 2L and a 3L ski jacket?
A 2L jacket has a membrane fabric plus a separate hanging lining and is common in insulated piste jackets. A 3L jacket bonds outer fabric, membrane and inner fabric into one, which is more durable and usually more breathable.
Why does my waterproof jacket feel wet inside?
Often it is condensation, not a leak: sweat that could not escape fast enough. Open the vents, layer lighter and refresh the water-repellent finish so the fabric can breathe.
Sources: gore-tex.com, the GORE-TEX membrane · gore-tex.com, ePE membrane · Snow+Rock · Ridestore Magazine · Powder7. GORE-TEX is a trademark of W. L. Gore & Associates. Product figures: TITTALLON product data sheets.
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