While layering is a very basic concept for folks interested in outdoor activities, there’s always someone who needs to learn the whys and wherefores of layering. Maybe you just got into playing in the outdoors, or maybe you were born and raised in Florida and just moved to Fairbanks with nothing but sleeveless tees and Bermuda shorts. Either way, this guide will get you through your options, and the rationale for layering.
First off, let’s talk about what our goals are. Human beings are resourceful creatures that have taken over the planet (that’s right bacteria, we consider ourselves to be the dominant species and we haven’t heard you disagree) and we live in every climate possible, but when it comes down to it we’re pretty fragile little creatures, and we tend to prefer our environments dry and warm. When you’re outside and exposed to the elements, your body loses heat through four different pathways: convection, conduction, radiation, and evaporation. The goal of layering is to keep you dry and warm to prevent the loss of heat through radiation, convection, and evaporation. Conduction heat loss is related to direct contact with liquids or solids, so unless you’re swimming or sleeping this will only occur through your hands or feet, which are fodder for a different subject. You achieve this by using a modular system, or layering system. If you’re pouring out sweat and there’s no precipitation, you take off your shell layer. If it’s raining or snowing but you’re hot, you leave on the shell layer and take off your insulating later. Depending on how active you’re going to be and how cold it is, you choose different thicknesses and weights of all three layers. The key is options, and having a layering system gives you the ability to regulate your temperature just like adjusting a thermostat.
The Base Layer
Clothing manufacturers like to refer to the area immediately next to your skin as a micro-climate, but I prefer to think of it as a concert venue, where sweat and moisture are like stinky hippies listening to a jam band, and your base-layer is a Scandinavian death-metal band playing glorious chords to chase all the hippies away. Realistically this model doesn’t make a lot of sense, but I hate hippies. (If you’re currently wearing patchouli as you read this, please accept my sincerest apologies but you smell like an 8th grader who hasn’t learned how to use deodorant.) Basically the long and the short of it is that if your skin is wet, you’re going to be colder because that water is going to evaporate, and if it evaporates it will chill your body down. The goal of any layer that you put directly against your skin is to move moisture away from your body, and every winter layering system will include at least this layer. Now, the magic special word all the advertisers use is “wicking”, but that’s only half of the story. Your cotton t-shirt wicks incredibly well. Paper towels wick incredibly well. What you want is something that wicks well and dries quickly, and maybe feels nice next to your giblets if you’re lucky.
There are a bunch of different materials used in base-layers, and tons of branded materials, but they basically fall into two categories, natural and synthetic. Natural materials that you will find in technical base-layers include wool (usually Merino) and silk. Synthetic materials are usually polyesters of some sort, or polypropylene. Merino wool has three big advantages: it’s very soft, it is the warmest material when wet, and it’s naturally anti-microbial, so even after wearing it for weeks on end without washing, it won’t stink. You will, but that’s a different story. The drawbacks are that wool is expensive, and doesn’t dry as quickly as synthetics. Silk is light, fairly durable, very soft, and dries faster than wool, but it’s also expensive and is very thin. It’s best used under tight clothing (it’s great under denim for around town wear) or for people that just want something light for warmer climates. Both wool and silk wick very well.
Synthetic fabrics vary significantly even within the same material used, because every manufacturer is looking to find a different way to get these materials to do something they don’t actually do very well in their raw form, which is wick moisture. Polyester and polypropylene are both hydrophobic materials, meaning that water doesn’t stick to them. While that makes them great at drying, they need to be either mechanically or chemically manipulated in order to wick moisture. Some use hydrophilic or hygroscopic coatings to help them draw in moisture, and some use special weaving techniques so that they can suck up moisture through capillary action–some fibers are even designed to be C-shaped in their cross section to help transmit water across them more easily. Polyester retains some odors, but there are antimicrobial treatments in many modern base layers to help mitigate this. There are simply too many different iterations of polyester-based fabrics to list, and the prices vary as widely as the performance, although the two are not necessarily positively correlated (thanks Statistics 101!). There are some great options from Terramar, Hot Chillys, Patagonia, but pretty much every major clothing manufacturer has some version or another of a polyester base layer. Polypropylene-based products, sometimes referred to by old school folks as just “polypro” are still used a bit in military-issue products, but very few manufacturers still use the stuff. Polypropylene clothing has been the fastest-drying clothing for decades, and as far as pure performance goes it’s still some of the best, if not the best stuff out there, but it is limited in its wicking abilities, and needs to be fitted fairly tight. The best example of modern polypro is LIFA, by Helly Hansen.
The Insulating Layer
You know how your hairs stand up when you’re cold? For most of us that aren’t built like Robin Williams, that’s just a vestigial response, because as naked apes we don’t have much to keep us from losing heat. Our base layer is helping keep us dry, but this layer is what’s going to hold in our heat. There are, as with base layers, both natural and synthetic insulating options.
On the natural side you have wool and down. Traditionally wool has been one of the most commonly used insulating layers, as it stays warm when wet and lasts quite a long time. While your tacky (or fabulous) Christmas sweater may do a damn fine job of keeping you warm, a Merino wool sweater will probably be a bit lighter and softer for hardcore outdoor use. Just this year, however, Ibex thought outside the woven-wool box and is using unwoven wool in baffling similar to down, our next natural insulation. Down has the highest warmth to weight ratio of any insulating material used in clothing, second only to the Argon insulation used by Klymit. Down is very compressible, very breathable, and very lightweight, but it has three big drawbacks. Down is the most expensive insulation out there, is a royal pain in the ass to wash (like, imagine a pain the ass, plus a crown and a scepter), and is utterly useless when wet. However, two new products have sought to fix the worst of these problems, the fact that down can never get wet. Both Downtek and Dridown use a gas-deposition nano-molecular proprietary hydrophobic polymer (say that ten times fast) to coat varying qualities of down so that the down itself cannot actually get wet. I’ve tested some of these products personally, and as a long-time fan of down, let me just say that anything made with this stuff gives me a gear-nerd-gasm. It really works. However, unlike wool, down can’t be harvested from live animals, so if you’re a friend of the feathered, you may want to look to other options.
Synthetic insulation basically breaks down into two options which are basically synthetic versions of woven wool and down. The first is fleece, or pile, the synthetic woven material that for the most part replaced wool as the insulation of choice from the 80′s until somewhat recently with the wool revival. Fleece is lighter, more compressible, and less expensive than wool, and it’s easier to wash. It does not wear as nicely as wool, but it still is a stellar option for temperatures down into single digits. Nonwoven synthetic downs like Primaloft are a great alternative in wet weather, as they dry quickly, stay warm when wet, are less expensive than down, are hypoallergenic, and are fairly close in weight-to-warmth ratio.
The Shell Layer
Some insulating layers are waterproof or windproof, negating the need for a shell layer in some circumstances, but for the most part this is your main protection against wind and precipitation. Shells these days come in two main varieties, hard shells and soft shells. Soft shells are sometimes waterproof, but more often are highly wind-resistant, water-resistant, stretchy, and soft fabrics. The ideal use for a soft shell is when the wind or precipitation isn’t particularly heavy, and/or when you’re doing a particularly aerobic or sweaty activity. If you’re cross-country skiing, snowshoeing or climbing uphill, or running in the winter, even the most breathable shells on the market aren’t breathable enough to keep up with the amount of moisture you’re generating in sweat, and you never want to be wet in the wintertime. As Les Stroud often says, wet+winter=dead. There are many different varieties of softshell on the market, but the two dominant materials appear to be Polartec PowerShield and Schoeller WB-400, both of which offer excellent performance and have a great DWR (Durable Water Repellent, arguably the most important aspect of any shell).
Hardshells these days are better than ever before. A hardshell is usually less flexible and breathable than a softshell, but is 100% wind and waterproof, and almost always breathable as well. While the original Goretex was decent stuff, it wasn’t until eVent hit the market that the game really changed, as eVent was SO much more breathable than the original Goretex or even Goretex XCR that it rendered them obsolete. Right now the three dominant materials are Gore-Tex’s Proshell, which boasts of the greatest durability, eVent, which has the greatest lab-tested breathability and lowest price, and Polartec’s Neoshell, which can be bonded to stretchy fabrics and claims it has the best real-world breathability. Realistically, all three of these are excellent products, but I tend to prefer eVent and Neoshell for a couple of reasons. eVent, owned by GE, doesn’t care if you brand your clothing as being made with eVent, so there are many companies out there like Mountain Hardwear that use it as an inexpensive prorietary fabric and just change the name. That means you get great performance for less, and I love that. Neoshell is commonly paired with flexible fabrics, and if you’ve never used a 4-way stretch hardshell, you don’t know what you’re missing–they’re way more durable, quiet, and comfortable than stiff shells. With Gore’s Proshell you get guaranteed quality, because they require that their fabric be used in very specific ways. However, in my opinion the very best of the best outerwear companies like Montane or Westcomb switched away from Gore-tex years ago. Plus, according to industry insiders and Outside Magazine, Gore-Tex has been a bit of a meanie-bo-beanie to their competiton.
A three-part layering system allows you to address the problem of how to stay warm and dry across many different activities. There is no perfect combination of clothing, and you may end up, like me, a bit of a jacket slut just for this very reason. While it can be awesome to have a product from each one of these categories to choose from depending on your activity, for most people a base layer, a fleece jacket, and a simple shell will cover your needs. You can specialize from there if necessary. Layer on young Padawan!