Waterproof/Breathable Shells — construction options
More tech geek stuff on waterproof/breathable shells. Non tech geeks might just skip down to the micro-rant, or read a real rant. One of the comments to my last post on w/b shells got me thinking about definitions – what’s the difference between the w/b shell types we hear about: 2-layer, 2.5-layer, 3-layer? Well, it’s a construction thing. Specifically, the construction as it relates to the interior layer of the garment. Each type of w/b laminate shell construction has pluses and minuses, which can help determine which best suits your needs.
First, I should mention that un-laminated waterproof shells, like raincoats, exist. I believe the standard raincoat is made of rubber or polyurethane-coated nylon. I don’t know. They’re heavy, don’t breathe at all, and, so far as I’ve seen, not cut for athletic movement or featured for technical use. Single-layer fabrics can be treated with waterproof coatings, but they wear off, just like a DWR coating will wear off over time. So, as per current technology, the only way to achieve true, lasting, waterproof/breathable protection is with these laminated fabrics. And you still have to keep up with the DWR coating, to keep the face fabric from getting saturated. Once that face fabric gets saturated, you have no effective vapor pressure gradient between your moisture on the inside, and the saturated fabric on the outside – and thus, no breathability. Some companies claim theirs will still breathe due to the temperature difference driving
breathability – and temperature does drive vapor pressure – but with a physical barrier like a laminate already there, this claim is bullshit. They can “prove” this breathability claim in a lab, yeah, but anyone who’s ever worn a laminate in the field, when the DWR has worn off and the face fabric is saturated, knows it’s bullshit.
Side note: you might not need a waterproof shell that’s also breathable. Sometimes you just want what amounts to an emergency rain smock. Will present some ideas on that another time.
By the way, any shell labeled “waterproof/breathable” by a reputable company will be seam-sealed. Either stitched seams with seam tape, or welded seams.
The w/b part is just the outer two layers – the face or shell fabric, bonded to the w/b laminate. Since the w/b laminate is fairly fragile, and thus needs protection, a hanging liner gets added to the inside of the garment. Doesn’t this make it three layers? Kind of, but the hanging liner doesn’t “count” in this type of math. The hanging liner helps wick moisture, and feels soft and comfortable, especially since they’re often made with brushed poly, soft mesh, or microfleece. Doesn’t usually feel like a garbage bag next to skin. But doing it this way adds considerable weight and bulk. They’re usually quieter, not as crinkly sounding or feeling. Sounds nice, but they’re heavy and bulky. Though I’m probably wrong here, I don’t think anyone makes a technical, climbing, w/b shell in 2-layer construction anymore. Since that hanging liner isn’t glued/bonded to the w/b barrier, it can actually make for pretty good breathability, but it’s hard to compare straight-up breathabilitiy across the garment construction categories; as I understand it, it’s a mixed bag, a can of worms, and goes above my pay grade – too many factors with construction, whether it’s bonded with glue or lasers and stuff, the distance from the heat/moisture source (your body) to the w/b barrier, and so on. 2-layer garments aren’t very compressible due to the hanging liner, which can also get bunchy over layers. These things best make for an around-town jacket, or maybe resort skiing, things like that. Usually good price-point pieces, not as expensive, not very technical.
These have a bonded inner liner (not hanging), but it’s not a full liner – hence the “half” part of 2.5. It’s like elevated specs, or parts of a bonded liner, sticking up off the w/b laminate, often in a dot or cool little printed interior pattern. Thus, there’s less bonded liner material on there. This decreases durability, and can allow contamination of the w/b laminate, because it’s partially exposed. It also makes it more susceptible to mechanically breaking down over time, thus reducing the shell’s effective life. But it does make for superb compressibility and the lightest weight. Smooth layering, too. Depending on construction, these can be super technical, stretchy, good features, good breathability, all that – or made as an emergency-only shell. Naturally, price therefore varies. You can get some good 2.5L shells for pretty cheap, and they aren’t necessarily bad. These emergency-type shells have some merit, particularly for summer alpine rock, like a “If you’re in the Park and hell unleashes with afternoon thunderstorms and it dumps for two hours emergency shell.”
A complete bonded liner is laminated to the inside. Thus, the w/b film is completely sandwiched between the inner scrim and the outer shell fabric. The scrim does a number of things well: it disperses water vapor (which helps keep it from becoming actual moisture) along the inside, to enhance breathability and keep you dry from the inside. Also has a much better next-to-skin feel than a 2.5L, like if you’re wearing it over a short-sleeved T (I find this of very rare value,though, at least with climbing – if I’m concerned enough to bringing a w/b shell, I’m usually up someplace where I’m wearing long sleeves, even in summer). Significantly, that bonded liner on the inside protects the w/b barrier (which, as we know, is prone to contamination), making for longer life (of the shell, that is) and, typically, better performance over the course of the shell’s life. A 3L fabric package also has greater tear strength and abrasion resistance. It usually has a softer feel than a 2.5L, but is usually heavier and less compressible (though Patagonia’s M10 – yes, I’m biased – does a remarkable job of being light & compressible for a 3L). Those who favor 3L shells tend to wear a hard shell for regular, dedicated use, and thus want something with a good feel and durable, solid performance day-in, day-out. But 3L shells are usually the most expensive – especially if they’re also technically dialed and honed-in enough to also be lightweight, maybe have some stretch, etc.
Again, all of this is if you’re going with, or need, a hard shell vs. a soft shell, which is a different topic – soft shells are great for many uses. An aside about definitions: there are no stone-set standards for what constitutes a hard vs. soft shell, but — ah, hell, time for a side rant.
Side Rant on Definitions:
My understanding, and one embraced by most in the outdoor industry, is that hard shells are waterproof, while soft shells are not. Since a laminate, or waterproof barrier, sandwiched into the garment makes these shells waterproof, all that sandwiching makes them feel “harder.” Soft shells, without that barrier, have a much softer hand. This definition makes sense, at least as I understand things in relation to the origins of soft shells. I think the concept really grabbed hold with winter climbing in Scotland, when people started realizing that their “waterproof” shells were leaving them soaked anyway, just from the inside. So, somewhat counter-intuitive as it may seem, some climbers started wearing jackets that were non-waterproof, but significantly more breathable. The jackets just resisted exterior moisture, slowing it down, but meaning that, in those nasty Scottish conditions, they’d allow some moisture to penetrate the shell fabric. But with such a breathable shell, and layered underneath with directional pile to help channel their own outward-driving heat, their own body heat would help keep them dry and combat the moisture that tried to enter. The shell and pile feel soft, and have no laminate barrier or stiff polyurethane coating. This “modern soft shell concept” works when you’re generating your own heat – it won’t work for watching Tiger Woods in the Kentucky Derby or whatever it is (obviously, I’m not a golfer), in a pouring rain. Though it might work for him, as apparently he generates plenty of heat.
Anyway, I’ve occasionally heard companies market something like a “waterproof soft shell,” which is a contradiction of accepted terminology. In that case, you’re just making up definitions however you want, aside from any semblance of reason. They might say “well, it doesn’t feel hard” (is that what…oh, nevermind) or claim it has a soft feel, but, fuck, ya can say that about anything, it’s wildly subjective. The claim of “waterproof” isn’t an exact science, either, but at least it’s some sort of standard. There are rules here Smokey, this is not ‘Nam. (OK, there really aren’t rules, but that doesn’t mean I’m over the line.)
Need to get back to work. Coming soon, maybe next week – my ideas as to which end uses might steer you to a 2.5 vs. a 3-layer shell. The 2-layer ones are usually best for walking to coffee shops in the rain. Or watching the Tiger Driving Open Master’s Derby or whatever it is.
Over the line!