Waterproof Construction (Layers)

Laminates and coatings are relatively delicate, and abrasion can damage the laminate or coating. Thus waterproof fabrics employ some type of skin-facing on the inner and outer of the laminate or coating for protection and are described as 2-layer, 3-layer or even 2.5-layer fabric. Here is brief description of each type of fabric.

There is an assumption that while 3 layer offers the greatest durability, 2 layer is the more breathable. Under laboratory conditions this is certainly the case. In practise however, the lining and the air gap between the lining and the outer fabric on the 2-layer garments inhibits the transfer of moisture vapour. Effectively, the breathability of a 2-layer garment if the same waterproof membrane is used is similar to the breathability of a 3-layer. So, if breathability is comparable why specify on over the other? The deciding factor between 2-layer and 3-layer is durability. For mountain sports where maximum durability is required, 3-layer is recommended.

2-Layer: The Most Affordable

These are comparatively basic garments, where a membrane or coating is applied to the interior of the face fabric (outer protection) creating two layers within the fabric. Often a loose-hanging liner, usually mesh, that is stitched into the interior of the jacket which protects the laminate or coating on the inside of the jacket. This suits many people, though some find hanging linings a little too loose and bulky-feeling. Two-layer jackets are usually a touch heavier than other designs, include more pockets and are primarily intended for day trips or urban activities. 2lyer is typically lighter and softer handle and is ideal for where comfort rather than durability is the requirement.

2.5-Layer: The light weight and packable.

These use a low-weight face fabric (first and outer protective layer), a polyurethane-based WP/BR laminate or coating (second layer membrane ) and a bare-minimum protective inner layer (more like a sheen than an actual layer, which is why it is considered a half-layer). Typically this inner layer is little more than a series of dots, a grid pattern or a spray of resins that provides a touch of slickness and abrasion-resistance. These garments, typically 500grams or less, are intended for ultralight weight travel and spacesaving for travellers. Walkers who favour more breathable soft shells as their principal outerwear often toss a 2.5-layer jacket into their packs just in case a deluge hits and they need full waterproof protection. If abrasion-resistance is not one of your key concerns, 2.5-layer garments deliver high performance for a comparatively modest price.

3-Layer: The Most Durable

Jacketsin this category offer rugged yet low-weight WP/BR protection. No coatings in general are used here, primarily laminates, with a membrane tightly sandwiched between the face fabric and a body-facing liner. Designers here seek to shave grams and add refinements as minute as rounded zipper pulls to avoid any angular edges on the finished product. Jackets in the category offer a sleek, athletic fit and face fabrics that can handle less-than-gentle treatment. This makes them well-suited for serious climbers and backpackers. Products in this category aspire to high breathability, high durability and relatively low weight, but can be a more pricy.

Soft Shells vs. WP/BR Fabrics

Traditional soft shells: These offer a water-resistant, tightly woven fabric distinguished by excellent stretch and breathability.

Pros: A good choice for highly aerobic activity (backpacking, Nordic skiing, snowshoeing, trail running, climbing) where flexibility and breathability are prized; capable of withstanding lighter showers.
Cons: If a soaking downpour hits, the fabric will likely become saturated at some point and you will feel wet.

Soft shells with a WP/BR membrane: These offer more stretch than a WP/BR garment, but with a reduced level of breathability (though one usually comparable with higher-performing WP/BR hard shells). But wait, is a membrane-equipped soft shell really a legitimate soft shell? It’s an odd evolutionary step for soft shells, no question, since their initial reason for being was their sensational breathability (coupled with modest rain protection).

Pros: Good for the same activities mentioned above, particularly climbing in wetter environments (where the extra stretch coupled with better weather protection pays off).
Cons: When the weather clears, it will not be as breathable as a membrane-free soft shell.

Waterproofs: How It Works

How do waterproof/breathable rain jackets work? Which is best: Gore-Tex? eVent? Polyurethane? A laminate or a coating? Which is more breathable and comfortable?

These are basic waterproof questions that often require technical answers. We’ll do our best to provide explanations in language that non-scientists and non-engineers can comprehend.

How Waterproof/Breathable Fabrics Work

Waterproof/breathable (WP/BR) fabrics made outdoor headlines in 1978 when outerwear designed with a Gore-Tex laminate was introduced. Since then many other branded WP/BR laminates have been created (eVent, Sympatex, many generics).

WP/BR fabrics are engineered to juggle 2 tasks:

Repel precipitation (to keep you and your clothing layers dry).
Provide an escape route for perspiration vapour (to accommodate evaporative cooling and maintain a comfortable body temperature during exertion in rainy conditions).

How is this accomplished? It requires some inside-outside work on the main fabric.

Inside

The interior (underside) of WP/BR waterproof uses one of the following technologies to become waterproof and breathable:

Laminates (which include Gore-Tex and eVent) are formed when a WP/BR membrane is bonded to the underside of a garment’s face fabric, as if wallpaper was applied to a wall—in other words, membrane (wallpaper) + fabric (wall) = a laminate.
Coatings are liquid solutions that provide WP/BR characteristics when spread across the interior of a garment—like applying a super thin coat of paint to a wall.

Outside

All waterproof exteriors (also known as face fabrics) are treated with a durable water repellent (DWR) finish. Even waterproof classified as water-resistant (which includes soft shells) carries a DWR finish. Here are some DWR fast facts:

A DWR affects only the exterior of waterproof and is separate from a laminate or coating.
Its purpose is to protect the face fabric from becoming saturated, weighing it down and causing any sensation of dampness.
A DWR accomplishes this by causing water to bead up and roll off the garment’s exterior.
DWRs do not inhibit fabric breathability.
Abrasion, grime and, to a lesser degree, laundering reduce DWR performance.
To remain optimally effective, DWRs must be regularly cleaned and periodically renewed using spray-on or wash-in products.

Next: a closer look at the inner workings of waterproof.

Laminates

The core of a laminate is its membrane. Membranes are made from:

Expanded (i.e., stretched) polytetrafluoroethylene, or ePTFE (sometimes also referred to as PTFE).
Polyurethane (PU) films.
Polyester films.

ePTFE

Gore-Tex and eVent, 2 widely recognized laminates, use membranes formed from ePTFE. An ePTFE membrane has a microscopic web-like structure that is amazingly thin—about 10 microns thick. (One micron equals one-millionth of a meter; the period at the end of this sentence measures about 500 microns.) W.L. Gore, the maker of Gore-Tex, estimates ePTFE contains 1.4 billion pores per square centimetre, or about 9 billion per square inch.

In spite all these microscopic holes, ePTFE is extremely resistant to water (hydrophobic, to use the technical term). Why? The reason most commonly cited is that pores in ePTFE are much smaller than the smallest raindrop (20,000 times smaller, according to W.L. Gore), yet large enough to allow water vapour molecules to pass through.

Yet the most scientifically sound reason is the fact that an ePTFE membrane is a solid that possesses what scientists call a low “surface energy” or “surface tension.” In this state it cannot be wetted unless it is contacted by a liquid with a correspondingly low surface energy (isopropyl alcohol, for example).

Plain water, though, has a high “surface energy.” This means that water molecules are strongly attracted to each other compared to other surfaces. Thus they always want to pull together into a shape that occupies the least amount of space on other surfaces, such as spherical drops. When water (high surface energy) contacts ePTFE (low surface energy), it quickly consolidates into rounded beads or droplets and slides off.

Place a drop of water on a Teflon cooking surface. It will not flatten and flow in all directions because the attraction between the molecules pulls them into the rounded shape of a drop. Meanwhile, the attraction between water and Teflon (PTFE) is so weak that no force pulls the water toward the Teflon.

So water can only penetrate ePTFE in 2 ways:

If water is applied with tremendous force. Wind-driven rain exerts a force of about 2 pounds per square inch (2 psi)—not nearly enough to penetrate ePTFE.
If the ePTFE’s low surface energy is altered due to contamination.

Contamination (caused by dirt, body oils, sweat, sunscreen, insect repellent or similar foreign matter) became the unforeseen foe of the original Gore-Tex laminate of the late 1970s. Those early laminates were designed with plain ePTFE membranes, unshielded against contaminants. The membranes worked splendidly—until they collected dirt and oils, which possess a high surface energy. Any time water makes contact with dirty, oily ePTFE, it now sees what has become a water-attracting high-energy surface and thus wets that surface. The dreaded result: leakage.

The way to protect ePTFE from contamination is to make it oleophobic—resistant to oils. In today’s laminates, Gore-Tex and eVent take different approaches to achieving this objective:

Gore-Tex

Gore-Tex takes a plain (unguarded) ePTFE membrane and attaches it to a thin protective polyurethane (PU) film, creating what is known in the waterproof industry as a bicomponent laminate. The PU layer is solid (technically speaking, monolithic) and shields the ePTFE from body oils and other contaminants.

Yet if the PU film is solid, it raises an inevitable question: How can such a combo breathe—or, to use more technical language, permit water vapour transfer?

Gore-Tex accomplishes this by formulating the polyurethane film to make it water-attracting (hydrophilic). This is commonly done by incorporating functional chemical groups that “like” water, or by combining the PU with other polymer materials that are hydrophilic, often polyethlyene oxide.

As a human perspires, sweat molecules are drawn to the water-loving PU film and adhere to its inner side, a process known as adsorption. These moisture molecules gradually seep through the solid PU film via diffusion. What drives their movement? The variance in concentration (also known as gradient, or differential pressure) on the 2 sides of the film.

Everything in nature moves toward equilibrium. Hot air moves toward cooler regions; moisture moves toward drier areas. So moisture with a higher concentration of heat and humidity (as generated inside a jacket worn by a vigorously exercising person) will move toward an area of lower concentration/lower heat (outside the jacket).

The difference in concentrations drives water molecules, with their positive charges, from one hydrophilic polyurethane molecule (negatively charged) to the next. The movement can be likened to child on a set of monkey bars, progressively swinging from one bar to the next.

Once on the outer side of the PU film, the molecules evaporate and escape through the ePTFE membrane as a gas, a final step called desorption. This adsorption-diffusion-desorption process delivers the magic of breathability (technically quantified as “water vapour transfer rate,” WVTR, or “moisture vapour transfer rate,” MTVR).

How does this process compare to the performance of an unguarded ePTFE membrane? Alas, it is slower. On occasion moisture can collect and condense on the inside of the PU film, creating a sensation of dampness inside a garment even though the garment is not leaking.

eVent

Created by a company called BHA Technologies (and now owned by General Electric), eVent was originally engineered for use in industrial air filters, then later discovered to be an effective WP/BR material. Though formed from ePTFE like Gore-Tex, the eVent membrane is protected from contaminants without an added PU film. In industry jargon, Gore-Tex uses a hydrophilic monolithic membrane (water-attracting and solid); eVent uses a hydrophobic microporous membrane (water-resisting and equipped with tiny, tiny holes).

So how does eVent shield ePTFE from contaminants? The process is proprietary (a trade secret). One textile scientist has described it as an “oleophobic coating applied in a supercritical fluid process.”

Dr. Alfred Lo, an engineer on the eVent development team, puts it this way: “It is accomplished with a molecular surface coating of the individual fibrils that comprise the open-pore structure of the ePTFE material,” he says. Without a PU film involved, he adds, perspiration vapour produced inside a jacket will be vented directly to the outside of the garment without first making the inside wet.

Gore-Tex vs. eVent

Some advantages of eVent:

The eVent membrane mimics the performance of an unguarded ePTFE membrane. Its 1-step direct venting approach produces fast moisture-vapour transport than the 3-stage adsorption-diffusion (plus desorption) process required by an ePTFE-PU combo. While no universally accepted lab tests for fabric breathability exist (discussed later in this article).
eVent performs with similar efficiency in both low and high humidity levels; Gore-Tex tends to favour higher-humidity environments and performs better after its PU film has collected some moisture. During rest stops in field tests that involved eVent jackets in cold, dry conditions, some testers were observed standing in steam-like vapour clouds due to the volume of moisture vapour escaping through the fabric.
Because the eVent laminate transfers vapour quicker than other waterproof/breathable, active users have discovered that sweat evaporates faster. So wearing eVent in cold weather for the first few times can chill users accustomed to less breathable materials. The solution: Wear another layer or a heavier layer of insulation with eVent shells.”
No WP/BR fabric can keep any high-exertion wearer totally dry, yet eVent’s high moisture vapour transfer rate means it is less likely to collect water on the interior of a garment than other WP/BR technologies.

Some advantages of Gore-Tex:

The bicomponent ePTFE-PU (hydrophobic-hydrophilic) combo has been used and refined for 30-plus years. Its ability to resist contamination has established a strong track record of durability. Meanwhile, the long-term durability of eVent’s approach to shielding ePTFE (individually coating microscopic filaments) is still being evaluated.

The long-term performance of eVent ePTFE will remain high as long as the garment is regularly cleaned. Dr. Lo recommends cleaning eVent garments with “reasonable frequency” to prevent dirt and oil from lingering in the pore structure of eVent’s ePTFE. Over time, dirt and oil could permanently plug eVent’s pores, impacting breathability.

The maker of Gore-Tex also recommends regular cleanings for garments that use Gore-Tex laminates.
DEET, an ingredient in many insect repellents, is a solvent that can reduce the surface energy of ePTFE. Avoid spilling DEET on any waterproof.
Gore-Tex Pro Shell, the latest incarnation of Gore-Tex
Gore-Tex is widely available in a variety of designs from a large number of manufacturers; eVent remains a relative newcomer with a modest number of styles.

Varieties of Gore-Tex

The Gore-Tex product line periodically changes. Original Gore-Tex (with unguarded ePTFE) has long been out of circulation. A version called Gore-Tex XCR is now used only in footwear. The latest Gore-Tex apparel product mix uses ePTFE-based laminates all styles, all of which carry Gore’s “Guaranteed to Keep You Dry” pledge:

Gore-Tex Pro Shell: Top of the Gore-Tex line. Best for rugged, athletic, demanding use. Available in 3- and 2-layer versions; 3-layer styles are usually a touch lighter and have a slight edge in breathability.

Gore-Tex Paclite Shell: W.L. Gore’s contender in the 2.5-layer product space, targeted at weight-conscious adventurers. The ePTFE membrane is shielded on the inside by a very thin layer that Gore-Tex describes as “an oil-hating substance and carbon.”

Gore-Tex Performance Shell: Used in garments intended for lower-intensity activities, from casual recreation to travel. Available in 2- and 3-layer versions. Excellent waterproof performance; good but not exceptional breathability.

Polyurethane Films

Many laminates use membranes made from a thin film of polyurethane. It is the same hydrophilic monolithic material used in Gore-Tex to form the protective wall connected to the ePTFE membrane in its laminate. On its own, a PU film performs the same waterproof/breathable function as it does when combined with ePTFE—moving moisture in an adsorption-diffusion-desorption “monkey-bar” process (described earlier).

So if a PU film can do all that, what function is ePTFE performing in the Gore-Tex laminate? ePTFE, due to it the microscopic texture of its filaments, bonds to PU in a way that allows the polyurethane film to be uncommonly thin—thinner (so far) than any stand-alone PU films used as laminates. Admittedly, the differential in thinness is measured in microns, but even such tiny variances can make a discernable difference in technical performance and the feel of a garment.

Newer PU laminates are narrowing the performance gap. Pertex Shield and Toray laminate Entrant DT for example.

Not all polyurethane is created equal. Polyurethane can be formulated to create a wide, wide range of products, from spongy foam to a hard faux-wood furniture finish. Thus whatever proprietary steps are taken to formulate polyurethane for use as a WP/BR membrane determines its performance attributes. The wizards who stir the most advanced polyurethane cauldrons are concentrated in Asia (primarily Japan), and the race to create better-performing PU films never ends.

Polyester Films

While not yet widely used, polyester-based membranes are a gradually emerging WP/BR category. The best-known example is Sympatex, which combines polyester (hydrophobic) and polyether (hydrophilic) components to create a pore-free hydrophilic film that transports water vapour by the adsorption-diffusion-desorption process used by polyurethane films.

Sympatex boasts that its film is exceptionally thin, a mere 5 microns, and thus capable of moving moisture vapour quickly. Its maker also claims it provides above-average stretchiness, which makes it comparable to PU films. (Laminates using an ePTFE membrane offer almost no stretch.)

In terms of performance, the general industry view of polyester laminates is that they slightly lag the best PU laminates in terms of breathability. Yet they offer a key sustainability advantage: Once worn out they can be recycled as long as they are bonded to a polyester textile that can also be recycled.

PU Films vs. ePTFE

Advantages of polyurethane films:

Usually results in lighter, smaller-packing garments.
Can accommodate stretch in a garment’s design; ePTFE laminates cannot. The inherent stretchiness of PU films may make them better equipped to handle hard impacts (such as a fall on rock or ice).
Lower cost, yet the newest versions are approaching levels of breathability comparable to 2-layer and even high-end, 3-layer ePTFE laminates.

Advantages of ePTFE:

The membrane itself (and fabrics that surround it) are better equipped for rugged use.
Better breathability than other laminates or coatings (though the breathability gap between PU films and ePTFE is narrowing).
Lower risk of condensation on garment’s interior (particularly eVent’s ePTFE, which excludes the PU layer used in Gore-Tex laminates).

Coatings

“Coated” waterproof uses a layer of polyurethane to cover the interior of garment, mechanically applied like paint brushed on a wall or mayonnaise spread on bread. Their chief appeal: Decent WP/BR performance for a low price.

Coatings can be used to fully seal a fabric and make it waterproof and nonbreathable. In the waterproof/breathable category, however, polyurethane coatings are formulated in 2 ways:

Microporous coatings: Include a network of infinitesimally small channels—too small for water to penetrate, yet large enough for vapour to escape. Most coated WP/BR waterproof uses monolithic-hydrophilic approach. How is a paint-like coating made porous? A foaming agent may be added so gas bubbles form and expand within the coating, creating permanent interconnected holes within the coating as it dries and becomes solid. Another method: Minute solid particles are mixed into the coating solution, causing tiny cracks and fissures to form next to the particles as the coating dries. This creates super-small passageways for water vapour to escape.

Monolithic coating: A solid, hydrophilic (water-attracting) layer that transports moisture via the adsorption-diffusion-desorption process described earlier in this article.

Unless the manufacturer identifies what type of coating is used, the 2 are visually indistinguishable. Which performs better? Likewise—differences are mostly indistinguishable. (Some garments, such as the Pertex endurance or Marmot Pre-cip)

Coated waterproof is the least sophisticated and least expensive entry in the WP/BR category. Its low cost makes it a popular choice among:

Outdoor explorers who move at a casual or recreational pace.
People who make only periodic visits into the countryside when rainy weather threatens.
Anyone trying to minimize weight or stretch a budget.

Coatings usually do not appeal to demanding outdoor athletes who routinely pursue high-energy, high-abrasion activities. But for travellers or casual/infrequent outdoor travellers, lower-cost coated WP/BR waterproof makes sense.

Coated WP/BR waterproof advantages:

In waterproof’s 2.5-layer category, coated garments are lighter and pack smaller than 2- or 3-layer laminated designs because, like 2.5-layer laminates, they include no lining, only a barely-there protective layer of raised lines, dots or resins to keep the WP/BR barrier off the wearer’s skin and give it a dry touch.
Less expensive than waterproofs that uses laminations, sometimes by triple-digit amounts.

Coated WP/BR waterproof disadvantages (compared to laminated WP/BR waterproof):

Less breathable.
Often a little heavier than laminated waterproof. When spread onto a fabric, polyurethane must fill in the hills and valleys of that fabric, allowing it to become comparatively thick in spots (though only by a number of microns). As a result, a coated garment may also feel somewhat stiffer.
Slightly lower tear strength of a textile.
When washed in mass-market detergents, micro porous coatings tend to collect some surfactants (cleaning additives or brighteners) that can decrease the surface tension of the coating, making it possible for water to pass through the fabric. Two solutions: Use at least 2 rinse cycles when laundering the garment (to purge all detergent residue); use a specially formulated, clean-rinsing laundry product for technical fabrics.

Breathability Comparisons

The elusive grail of achieving bare-skin breathability in waterproof has challenged designers and frustrated wearers for decades. A key obstacle for waterproof, windproof garments is that little or no air can pass through them—technically, they are not air permeable. (Try blowing air through a sleeve or body panel of a WP/BR jacket.)

When active, perspiring human bodies stir up a moist microclimate inside a garment that cries out for dispersion and evaporative cooling. At very high rates of exertion, moisture from sweat can begin to collect inside a garment, raising the potential for overheating when active or chills (due to evaporative cooling) when resting.

Testing

A variety of tests exist for measuring a WP/BR fabric’s water vapour transfer rate (WVTR; a clinical term for what most consumers call breathability as they perspire). Most of these tests carry head-scratching names (upright cup test; inverted cup test; sweating hot plate test). Regrettably, none has emerged as the consensus reference standard among manufacturers by which all waterproof breathability is evaluated.

This is an important factor for consumers to recognize when they feel confounded by the complex-looking lab results they see promoted by some waterproof manufacturers: No universally accepted standard for fabric breathability exists.

Commonly Cited Test Figures

Even though no universal breathability standard exists, outerwear manufacturers persist in trying to sway consumers by publishing impressive-sounding (though hard to fathom) lab results in their promotional materials. The following explanation may elicit a too-much-information response from many readers, but we believe some interpretation of these numbers is needed.

Over time, the use of the following measurements has grown increasingly commonplace:

Water resistance: The amount of water pressure (in millimetres) a fabric sample can withstand before leakage occurs. For example, agarments using a laminate can claim 20,000mm of hydrostatic head or water pressure.
Breathability: The amount of water vapour (in grams) that can pass through a square meter of fabric during a 24-hour period. Using engineer’s shorthand, a laminate reports 20,000g/m²/24hr.
Wind resistance: The maximum wind speed a fabric can block is normally measured in cubic feet per minute.

Wind Resistance/Air Permeability

A fabric’s wind resistance is usually displayed in miles per hour (mph) or cubic feet per minute (cfm). The most common test for measuring wind resistance in fabrics is the Frazier Air Permeability Test.

The Frazier test measures the amount of air (in cubic feet) that can pass through 1 square foot of a fabric sample in 1 minute at a pressure differential equal to a wind speed of 30 mph. Such numbers are only sporadically promoted for waterproof and emphasized more on garments designed specifically for high-wind conditions.

Most waterproof/breathable waterproof fabric is also promoted “windproof.” Wind becomes a concern to people who are moving at a high velocity (skiing or cycling) or caught in a storm that involves strong winds. Wind can deprive our bodies of heat and moisture, leaving us feeling chilled. Wind can also cool us when we are vigorously exercising.

With waterproof, usually our greater concern is air circulation. Air movement enables our bodies to avoid overheating when active while wearing waterproof. This is why venting a rain jacket (using the main zipper, core vents or underarm zippers) is a key tool for regulating our comfort level when active. (Note: eVent rain jackets often exclude underarm zippers due to elevated breathability of their laminate.)

While windproof, most waterproof offer no air permeability. Soft-shell fabrics that include no laminates, meanwhile, offer good air permeability (and thus superior breathability). The downside to unlaminated soft shells: They cannot repel heavy precipitation. Even so, some high-energy wilderness travellers accept that trade off and choose laminate-free soft shells as their primary outerwear piece in order to maximize breathability.

Summarizing wind resistance/air permeability:

Most waterproof is considered “windproof,” though for fabrics no industry-wide windproof standard exists.
Air circulation helps cool a vigorously exercising person who is wearing waterproof.
Because most waterproof offers no air permeability, the use of vents (including a jacket’s main zipper) is an important tool for regulating air circulation.
Laminate-free soft shells offer generous air permeability but minimal protection from a sustained downpour; relying on a soft shell as one’s principal outerwear is a decision best left to experienced walker.

Durable Water Repellent (DWR)

The first line of defence for waterproof is not a laminate or coating but the durable water repellent (DWR) applied to the fabric’s outer surface.

All waterproof/breathable garments are treated with a DWR finish (as are most water-resistant soft shells). DWRs do not inhibit breathability because they do not coat the textile surface; instead they bond to the textile’s fibres and do not fill in the interstitial spaces between those fibres.

The purpose of DWR finish: Allow a garment’s face fabric to shed water, prevent saturation and keep water from sitting atop a WP/BR membrane. Garments remain light when they avoid becoming waterlogged.

DWR works by the contact angle or surface tension created when water contacts a textile. An optimized DWR forms a chemical chain of microscopic, tightly packed vertical “spikes” on the outermost fringe of a garment’s exterior. This dense, spiky buffer leaves no room for water to spread out, forcing it to form in round droplets. As such it beads up and swiftly slides off the fabric, having no opportunity to flatten out and seep into the textile.

Fluorocarbons (sometimes called fluoropolymers) can create the steepest angle and are the most common DWRs. Silicone and hydrocarbons are also used. Nonchemical DWRs are being studied, though none offers the performance standards achieved by chemical DWRs.

DWRs are at their best when new, but their performance can diminish with use. Their molecular chain, says Verniers, is masked by dirt and oils and can also be affected by abrasion. Such things reduce the surface tension and allow water droplets to flatten, spread out and penetrate the textile.

Regular laundering and a brief spin a clothes tumble dryer (about 10 to 15 minutes at medium heat) can revive a DWR. After prolonged or rugged use, though, waterproof will likely need to have its DWR reapplied. Spray-on and wash-in reapplication products from companies such as Granger’s, Nikwax to accomplish this goal. I prefer a spray-on products, since wash-in products may impact a garment’s breathability.

Some Subjective Observations

Other factors beyond waterproof’s WP/BR technology should influence a purchasing decision: Weight; packability; appropriateness of the face fabric for your primary activity.

Other factors beyond waterproof’s WP/BR technology will impact wearer comfort: Lots of good, breathable waterproof choices exist, and some (particularly 3-layer laminates) tend to consistently outperform others in breathability. But even their performance expectations can be overwhelmed by overly aggressive use. A key objective when wearing waterproof during exertion is to avoid moisture build-up inside the garment. The best defence: Be alert and actively manage your comfort level.

Personal metabolism: If you heat up easily, modify the pace of your activity.
Exertion level: Same principle; slow down or speed up as needed.
Weather conditions: If it’s warm and steamy out, no waterproof feels comfortable; if it’s cool and dry, keep a light insulating layer handy for rest stops; in other words, be alert and nimble; adapt as conditions dictate.
Clothing worn underneath: Shed a layer if you’re uncomfortably warm.
Use of vents: If you waterproof has underarm zips, core vents, use them (in addition to your main front zip) to speed sweat’s evaporation.

Polyurethane and polyester laminates: Beyond eVent, PU and, to a lesser extent, polyester laminates are also challenging the dominance of Gore-Tex. The bi-component Gore-Tex membrane includes an anti-contaminant polyurethane layer but for years has outpaced PU competitors because its PU layer was the thinnest around (due to the structural support provided by its ePTFE layer). Yet newer PU membranes claim to offer comparable performance.

Coatings: Casual explorers, weight-conscious travellers or budget-minded shoppers are usually quite happy with lower-cost WP/BR coated waterproof. Just be aware that if you are in one of those groups and you evolve into a high-energy adventurer, most likely you will want to upgrade to a higher-performing WP/BR technology.

Maintenance: Clean your waterproof regularly to keep it performing at its best. If you notice wet blotches on the face of a rain jacket, you need to revive its DWR.

The future: Textile technology is a fascinating field. Ideas and innovations are being hatched all the time. Accept the fact that today’s whiz-bang technology may become tomorrow’s dinosaur.

Want a comfort boost on your next outdoor adventure? Ditch those cotton undies and that souvenir concert T-shirt and upgrade to a moisture-wicking base layer (also known as a first layer or performance underwear).

Wicking underwear can benefit any physically active person—from athletes to builders—and is a must for every earnest outdoor explorer, whatever the season. As the next-to-skin layer of any layering system, its role is to move moisture away from your body.

Waterproof Shell