The very idea of a waterproof and breathable shell poses an obvious challenge: How can it be breathable, which implies permeability, yet waterproof, which would seem to mean impermeable? The outdoor industry has almost universally settled on an answer in the form of a three-layer fabric (there are also two- and 2.5-layer shells, but three is generally considered the most durable and best suited for winter), made up of an exterior textile, a technical membrane and a backer textile, all of which are bonded together. The basic idea is that this fabric — specifically its membrane — prevents outside water from seeping in while also allowing sweat and heat to escape, creating a piece of outerwear that can be used for active outdoor pursuits in the cold weather.
The outer textile of most three-layer shells is made of a rugged nylon or polyester that’s coated with Durable Water Repellent (DWR). The inner membrane is a microporous fabric, typically made of ePTFE or Polyurethane that acts as the shell’s primary waterproof and breathable layer. It’s the secret sauce. The backer textile is a thin layer, usually gauze, that’s laminated to back of the membrane, which eliminates the need for a liner.
While the waterproof and breathable technologies are all generally related in the way they function, several brands have proprietary technologies, among them Gore-Tex, NeoShell, eVent, Schoeller and Dermizax NX. Discerning one technology from another can be difficult, in part because the technology is kept under lock and key, but also because the technology requires an understanding of terms like “phase change” and how things work on a molecular level. So we asked the chemists, engineers and designers who worked hands-on with each. Note that there are plenty of other proprietary technologies like Marmot MemBrain and Helly Hansen’s Flow membrane, but we chose technologies that are available across a variety of brands. Below are our experts’ responses, along with three winter shells that incorporate the associated technology.
About Comparing Technologies:
Finding empirical data to compare waterproof-breathable technology is difficult. For one, there are numerous ways to test waterproofness and breathability. According to Stephen Kerns, President of Schoeller Textiles USA, most companies use a preferred testing method that lends itself to their product’s best result, which may not the best for others. For this reason, most companies “steer clear of marketing comparisons on breathability and waterproofness claims with other companies,” he said, as it “becomes a slippery slope.”
Expert: Mark McKinnie, Gore’s Product Specialist in the UK
Of Gore’s technologies, which include Gore-Tex Active and Gore-Tex Paclite (among others), their Gore-Tex Pro shells are the toughest. Each has a three-layer construction and is designed specifically for extreme winter activities, like mountaineering, ski mountaineering, free riding and mountain guiding. “The basis for the membrane used in Gore-Tex Pro is ePTFE,” says Mark McKinnie, Gore’s product specialist in the UK. “In simple terms, the membrane is a sheet form of ePTFE, but in reality it’s a highly complex and confidential process to achieve the microporous structures necessary.” This ePTFE membrane has 9 billion pores per square inch, each of which keeps water droplets out and allows water vapor (perspiration) to pass through.
Internally, McKinnie says they call this ePTFE membrane “the engine,” as it does the most to make the shell waterproof and breathable. However, McKinnie adds that the first priority of any Gore-Tex Pro shell is durability, with breathability coming in “a close second.” Each Pro shell is meant to wear in extreme weather for weeks or more at a time. In addition to its ePTFE membrane, the shells rely on its other two layers for toughness. Their backer textile features Gore’s Micro Grid Backer technology, which is a non-restrictive and breathable lining, and the outer face textile is DWR coated and thought, equal to or greater than 40 denier.
Brands that incorporate Gore-Tex Pro: Arc’teryx, Mammut, Burton, Salomon
Modon Jacket by Arc’teryx $699
Nordwand Pro HS Hooded Jacket by Mammut $775
Super Alpine Jacket by Patagonia $599
Expert: Chris Pew, TREW’s Founder & Director of Product
“Dermizax NX simply sets a new high-water mark for breathability with waterproof shells,” says Chris Pew, founder and the director of product at TREW, where he’s responsible for design and development. Dermizax NX has a higher breathability rating (40,000 grams) than Gore-Tex Pro-Shell 3 Layer and Marmot MemBrain (both 25,000 grams), according to TREW. Traditional microporous membranes need to drop their waterproofness to around 10,000 or below, says Pew, in order to enhance breathability. “We set 20k waterproof as our absolute standard for outerwear, so then the challenge is how you can maintain that standard and still significantly alter breathability. Dermizax NX is a nonporous membrane, so they overcame this challenge at a molecular level.”
The membrane functions similarly to polyurethane or ePTFE: “The concentration of water vapor on the inside of the garment dissolves through the membrane to reach the lower levels of water vapor concentration on the outside of the garment,” says Pew. “The more you sweat the better it works.” In Dermizax NX, Toray created a structure that allows for a faster transmission of water vapor.
The target customers for Dermizax NX, according to Pew, are season-pass-holding skiers who delve into the backcountry. “We tried to create garments that are equally as comfortable during a storm day at the resort or for a day on the skin track. The beauty of the NX membrane is that it allows us to create high-performance garments that are uniquely comfortable and appealing for a wide range of outdoor users.”
Brands that incorporate Dermizax NX: TREW, KUIU, Bergans of Norway
Andermatt 2L Jacket by Ortovox $749
Wander Jacket by TREW $419
Storen Jacket by Bergans of Norway $499
Expert: Michael Cattanach, Polartec’s Global Product Director
According to Michael Cattanach, Polartec‘s global product director, who is also responsible for product innovation at the company, the main goal with Polartec Neoshell is breathability. The brand wanted a technology that allowed sweat and heat out of the garment, while also being comfortable. It’s easy, Cattanach says, to make something waterproof. The problem with these thick layers of polyurethane, which keep water out, is that “they’re about as breathable as a heavy oak door.”
“To truly differentiate our waterproof breathable fabric, it’s been about finding a balance of waterproofness and true air permeability,” says Cattanach. Polartec Neoshell allows a small — but significant — amount of air through the membrane. This allows the body’s heat and moisture to escape without requiring a phase change, from vapor to liquid, for moisture to move through it. In this way, Neoshell can regulate a person’s core temperature quickly.
Polartec Neoshell shells are geared toward winter outdoorsmen who sweat often. Cattanach says that the obvious wearers of Neoshell jackets are day hikers, high-output climbers and general alpinists, but more people who used to consider waterproof shells a last resort, like cyclists and runners, are now wearing NeoShell for its breathability. “We now have a technology that allows people to rethink how they dress for activity. They no longer need to consider keeping their shell in the bottom of their pack for emergencies, they can keep it on for the widest range of activity levels and conditions.”
Brands that incorporate Polartec Neoshell: Strafe, Marmot, L.L.Bean
Lab Coat Jacket by FlyLow Gear $525
Storm King Jacket by Marmot $550
Outerwear Cham 2 Jacket by Strafe $465
NeoShell Jacket by L.L. Bean $349
Expert: Chad Kelly, Director of Sales and Product Line for eVent fabrics
As with other membranes, eVent‘s primary goal was to create the most breathable and fully waterproof textiles on the market. Chad Kelly, the brand’s director of sales and product line who has been with eVent fabrics since its inception in 1999, says DValpine technology separates them from competitors.
“eVent’s difference is that the membrane is air permeable and has an open-pore structure,” says Kelly. “A patented membrane treatment keeps the pores of the membrane open to allow what we call one-step ‘Direct Venting;’ in other words, body heat and moisture can pass through the eVent membrane in vapor form.” Without the need for moisture to change phase, sweat and heat are released more quickly.
Jackets with eVent waterproof fabric have, at their heart, an air-permeable membrane made of ePTFE, says Kelly. The membrane, which is treated to prevent contamination, has an open-pore structure to allow body heat and moisture to pass through. “This is the patented difference of eVent and also what is meant by air permeability.”
Again, the target users of eVent are snow-sport athletes who are highly active, like free skiers or alpine climbers. “Our technology is designed to keep you dry,” says Kelly, “both generated by hard use on the inside of the jacket and from the weather on the outside of the jacket.”
Brands that incorporate eVent: Rab, ColdSmoke Apparel, FA Design
3L Subsonic Jacket by FA Design Outerwear $478
Latok Alpine Jacket by Rab $400
Waterproof M65 Field Jacket by ColdSmoke Apparel $399
Expert: Stephen Kerns, President of Schoeller Textiles USA
Schoeller Textiles sought to create a high-performance laminate that is waterproof while going further in breathability and eco-friendliness, says Stephen Kerns, the company’s president. The result was c_change. In addition to performing dynamically in all temperatures and moisture conditions, the membrane has “below detectable levels” of PFOA and PFOS.
“The invention of this membrane was inspired by the principle of the pinecone, which opens in dry warm weather and closes when it gets cold in order to protect the seeds,” Kerns says. “c_change reacts in a similar way to changing conditions. With a temperature rise from 10 to 20 degrees Celsius (50 to 68 degrees Fahrenheit), the moisture vapor transport increases by 50 percent. Similarly, the polymer structure of the membrane contracts when the temperature drops and heat retention increases so that protection and comfort are guaranteed under all weather conditions.”
Any downside to c_change — for instance, the membrane becoming a little less breathable as the temperature drops — Kerns says is a tradeoff to producing a high-performance membrane that’s also environmentally friendly. The target consumer for c_change, Kerns says, is someone looking for the ultimate comfort and waterproofness in stylish laminates, which range from “outdoor pursuits to urban sophistication in our new Cosmopolitan collection.”