Send any comments to the maintainer Roger Caffin
Rainwear has proven to be a hot topic for discussion and dissension. There is a lot of myth in this area, and fair bit of ignorant bigotry as well (I paid $xxx for this jacket: it has got to be better than the cheaper ones!). We will start at the beginning with what you really need from a jacket, and then review the underlying theory of how a jacket works (did you think you could skip this?). With a better understanding of what is going on, we will then discuss all the technical bits and current state of the art.
We will try to give some idea of what is on the market. This is where things get a little rough: many people have very strong views that brand X is good and brand Y is terrible, but putting that in print can be a little risky. Yes, I have been attacked by some vendors of more expensive jackets (usually but not always Gore-Tex) for daring to suggest that their super-deluxe is not better than the rest, let alone the cheaper ones. Added to that, models come and go, and I am not going to try to be model-specific. If any manufacturers or distributors wish to provide more information (to set the record straight?) it will at least be considered. Finally, we will look at some designs and materials, including a bit of a look at what is happening in both advanced fabric design and overseas gear designs. You will be surprised at the possibilities.
What do you (really) need in a jacket, and how do the available materials provide this?
Ultimately, what you need in the bush or the mountains is protection from hypothermia. Actually being wet is of little consequence.
This means you need protection from both wind and rain. But you need this under two quite different wearing conditions. The first is while you are being active; the second is while you are standing around. Combining the two is difficult. Adding to the complication are threee different weather conditions: cold wind (simple), really cold wind and snow (still fairly simple), and heavy rain (impossible). In this FAQ we are mainly concerned about rainy weather. If you think this is difficult in Australia, spare a thought for the Kiwis on the West Coast.
The first thing to point out is that if you are waving your arms around - going through some scrub for instance, the water on your hands and the scrub is going to go up your arms and wet your sleeves from the inside. Rain hitting your face is going to run down your neck and wet your shirt front. Sweat on your back is not all going to escape, and it will wet your back. And finally, rain running off your jacket will hit your knees and wet all your trousers, and that will wick upwards. You can wear waterproof trousers as well, but this is getting a little complex and expensive. Unless it is really cold and windy, it is also too hot to be comnfortable. Bottom line:
If you are active in the rain, you are not going to stay dry, no matter what the claims on the label.
Better add a second bottom line here, although it is mentioned elsewhere as well. You can forget 'waterproof' shoes - like joggers with 'Fred-Tex' membranes. All shoes have this great big hole at the top, and when it is really raining water gets in there. It gets in even faster if you walk through a creek of course. Once the water has filled up your shoe, the Fred-Tex membrane will do an excellent job of keeping it there. At least mesh joggers drain quickly. But I will make an exception for snow conditions: membrane joggers can be very good there, with WP gaiters.
Some manufacturers "test" their designs on a clothing dummy under a shower. They do up all the zips, flaps, cuffs and so on, and hang the arms straight down. Then the shower head is pointed at the back of the head. Gear testing is commendable, but these test conditions bear no resemblance to the real world (unless you are an ABC reporter standing in front of a camera with your back to the wind). What a jacket can do is limit the amount of fresh cold rain pouring into your clothing, or maybe help you keep the water inside your jacket warm. That is, unless it is warm enough that the inside of your jacket turns into a sauna (real world!) and you start to die of heat exhaustion. So you open your jacket up for cooling - and get wet anyhow. Face it: if you are active you will get wet.
In fact, what you usually need is protection from the cooling effects of the wind, especially on your wet skin. If you are dry you may not need waterproof gear to get this. Just a tight weave fabric (a 'windshirt') will usually shed the wind enough. If it is really cold, maybe with (dry!) snow, you don't really need a waterproof jacket either, just something to shed the wind and snow and to keep the warm air in your clothing. If there is warm tropical rain, there's little point in wearing a jacket and you won't get cold anyhow.
However, the combination of cold wind and cold rain can make you very cold, and you should note that there are two channels for losing heat even when you you are wearing rainwear. The first is by the continuous flow of fresh cold water onto your head and shoulders, and the second is by evaporation from the surface of the jacket.
It may not be immediately obvious that cold rain falling on your head and shoulders will suck heat out of your body - until you start to think about it. But it is very true, and this fact has been greatly ignored by most people here in Australia. Remember: water does not hurt; cold does. Overseas people have been known to use umbrellas in the rain while walking. Seems silly? Not quite. The unbrella keeps the rain off your body just fine and you don't get sweaty. Of course, this is less effective if there is scrub or wind around, and we have plenty of that here in Australia. But it does suggest that a large waterproof hat might have some value under some conditions, doesn't it? Another way of protecting your head and shoulders is to use a cape or poncho, and this can be very effective. It is dealt with below.
In bad weather this can be a serious problem, but it can be managed. To go any further we have to get a bit technical and look the details of the wet surfaces and the conduction of heat. Not all of this is totally obvious. Bear with us.
We start with the outer surface of your jacket. If it is wet the water on it will evaporate in the wind and make the outer surface really cold. If the outside of the fabric is cold, the inside of the fabric will be cold, and will probably collect condensation from your body. When this cold damp surface touches your skin, your skin will will get cold. This is what hurts: cold skin, leading to hypothermia (body temperature substantially below what it should be). Who cares about being wet if you are warm? Don't believe me? Think hot shower or hot spa: no problems there!
An obvious solution is to stop the fabric surface from getting really wet. (A traditional cheap PVC raincoat is really good at this, but it has other disadvantages.) We can try to stop the fabric surface from getting wet by making it water repellent, so water does not 'stick' to the surface. One way of doing this is by coating the fabric with a Durable Water Repellent (DWR) coating. The two main forms of this are silicone and fluoropolymer chemicals. The conventional current versions of both wear off fairly quickly through abrasion, although the fluoropolymer seems (so far) to be more robust if properly bonded to the fabric. However, this is changing with some of the latest silicone coatings: see the bit at the end on alternate designs and materials. When you have a good coating of one of these DWRs on the fabric the rain will bead up and roll off: the fabric itself stays fairly dry. A dry fabric does not get very cold, and doesn't leak water. If this is the path you are following, maintaining the DWR coating on your jacket is crucial. In fact, some would argue that the DWR coating is (far) more important than whether the fabric is actually waterproof. There is much truth in this, leading to the Soft Shell concept.
But note that this is just one way of keeping your skin warm. Alternatives include making the whole fabric water-repellent, so none of it gets wet, and making sure that a wet outer surface does not get to touch your skin and cool it down. These are not quite conventional approaches.
Let's think about the inside of the jacket. If the outside of the fabric is wet and cold, the inside will be cold too, and it will quickly get wet from sweat condensing there. This sweat and wet fabric will start to stick to your skin, and now the cold really starts to trickle in (or your body heat starts to leave). You can limit this heat flow somewhat by having a thermal top or other thickish clothing layer under your jacket, but obviously a light cotton shirt is not going to work. Cotton fabrics are notoriously cold when wet.
A point few vendors ever bother to mention is what happens when the surface of the fabric finally gets wet. If the outer surface of your jacket is wet, you can forget about most of the "breathability" the fabric is meant to have: it has just been reduced way down (albeit not quite to zero). So, as the outer surface chills from being wet, condensation and cold inside can follow if you don't take special steps to handle it.
Less obvious is the idea that follows on from this. Having a bulky layer on under your jacket, even if it is not really a top-rate thermal insulator, will keep you far warmer than you expected. Even a thermal top may provide enough bulk between your skin and the jacket to stop the condensation from reaching your skin. We aren't talking about real insulation here: just a physical spacing layer. If your skin can stay dry and warm, the heat from it can actually drive moisture out of the layer surrounding it. So there is a trend today towards rainwear which is not 100% waterproof, but does have this insulation layer under it. You probably won't see a lot of it in Australia yet, but the Europeans knew about it long, long ago and the Americans call it Soft Shell and think they invented it recently.
This term was used above. It means that the fabric can let water vapour pass through, while blocking liquid water. There are lots of pretty diagrams in the mountaineering catalogues which illustrate this. Different manufacturers claim all sorts of enhanced breathability for their own products, but most of them omit a critical detail: what conditions are needed to use the breathability.
Think of little ping-pong balls (or water molecules) bouncing around on either side of a wall which has small holes. Every now and then one of the balls will hit a hole and pop through. If there are lots of balls on one side and only a few on the other, those on the numerous side will flow more quickly through the holes: they 'win'. If the balls on one side are packed more densely than on the other side, they will 'win'. If the balls on one side are racing around more quickly, they will 'win'. In short, the side that gets to pump the most little balls (ie water molecules) through the wall 'wins'. Those of you who remember Maxwell's Demon may recognise this description. I should add that the analogy is rather loose: some fabrics really do have 'holes' through which the water molecules can pass, while other fabrics technically use a 'diffusion' process instead.
In real terms, this means we need either a temperature gradient or a vapour concentration gradient across a fabric to get vapour transmission, or both. So most fabrics work well when the outside air is a very cold and very dry - high alpine conditions in America or Europe maybe. But when the outside air is warm and humid, like we get so often around Sydney or Queensland, you are dead out of luck. The vendors don't tell you this of course.
It has been suggested that an increased air pressure can make this transfer of water vapour work. By itself, it won't. And there is no way you can get an increased air pressure inside your parka anyhow. You would end up looking like the Michelin Man*. Nice idea but totally wrong.
What this means in practice is that those expensive fabrics which claim increased breathability over their competitors won't actually be able to deliver much in the way of benefit in many parts of Australia, once you get out in the bush. Yes, this means that under many conditions a cheap PU-coated light nylon fabric may work just as well (or poorly) as the most expensive heavy 3-layer GoreTex fabric. However, the manufacturers and distributors are remarkably loath to admit this as big-ticket items make more profit.
On this subject, you might want to read Ranolf Fienne's book "Mind over Matter". He insisted on wearing cotton jackets in the Antarctic for an unsupported ski crossing. His argument was that breathability is crucial in stopping any build-up of ice inside the jacket, and that cotton is still the best. Fine, but note that he was in dry conditions and way sub-zero, so actual waterproof ratings were largely irrelevant for his needs. An interesting perspective. On the other hand, his partner on the trip wore a Gore-Tex shell, and I don't recall much comment in the book about any comparison, which suggests that the Gore-Tex worked under those conditions. The modern Epic fabrics and soft-shell concepts carry this theme forward.
* He's called Bibendum. The first Michelin advertising showed the character drinking a glass of nails (to show that it didn't feared flats) and saying "nunc bibendum est" ("Now it's time to drink" in Latin). People misunderstood the sentence and the name Bibendum became associated with the Michelin Man. [My thanks to "Maki"
I am going to crib a bit here from a web page by BHA, the manufacturers of the eVent fabrics. They have such cute diagrams which do an excellent job of explaining what happens when you sweat inside a waterproof fabric. (This does not mean I am endorsing eVent fabric.) They put it thus (slightly paraphrased).
Sweating is a natural process, part of what you could call the natural air conditioning of the human body. When we exercise our muscles produce heat. The body must stay at a ceertain temperature, so it must find a way to cool itself. We balance our core temperature by sweating, which is effectively evaporative cooling.
To support our 'human air conditioning' waterproof fabrics must let the sweat out. If you sweat more than the fabric can handle, two things happen (simultaneously):
As a result you overheat. We call this the boiler effect. Eventually you soak in your own sweat - the sweat that is trying to cool you down. Worse, when you stop exercising all that sweat inside your jacket, boots and gloves is still there and makes you feel cold and miserable. The physiological experts call it "post-exercise chill." Sound familiar?
All humans sweat. A lot. Especially athletes. Humans simply walking produce 0.25 to 0.5 liters of sweat per hour, and up to 1.5 liters during strenuous activity. [This may or may not apply to bushwalking in mild or cold weather: I certainly don't drink that much water on a cool day! - RNC] All this sweat has to move through your clothing system, your gloves, and your footwear. If you're wet, you're miserable. If you're dry, you're comfortable. eVent fabrics allow sweat to quickly evaporate to the outside, keeping you dry on the inside. [I let them have a little 'commercial' at the end for the use of their diagrams - RNC]
If you can keep the surface of your jacket or clothing from getting wet, the rest of you and your clothing inside it will stay warm and (fairly) dry. Neither will it gain much weight in bad weather. So if that's how your jacket works, it makes a lot of sense to do a bit of maintenance on it to keep the water beading off. Actually, this is probably more important than either waterproofness or breathability, under typical Australian East Coast conditions (outside the snow country). In tropical far North Queensland ... give up!
The initial DWR coating is applied to the basic fabric under optimal conditions during manufacture. It is almost always a fluoropolymer today, and should last a fair while. You can often restore some of its performance by ironing the fabric or warm tumble-drying it. What this does is make the DWR polymer coating soften and flow around the fibres again, to cover up the worn patches on the surface. This does work - until you run out of coating, which seems to happen all too quickly.
Just how good can a DWR be? The photo to the right is of some GoLite Whims trousers. The fabric is basically uncoated polyester with a DWR on it. I had paper towel inside the bit show and sprayed it for a while as shown. Water prenetration was very close to zero. OK, after a year or two of use the fabric would need to be washed and maybe retreated - but the stuff does work.
You can buy various brands of replacement DWR coating at walking shops to replace the original coating when it wears off. There are several brands: I know of Nikwax, Grangers, Revivex and Atsko at least. (I use the Atsko fluoropolymer myself.) Follow the instructions on the containers, but do be careful with the iron and don't melt the jacket! And read the next section on washing the fabric.
Caution - some forms of Nikwax may be wax-based rather than fluorocarbon-based. In my experience, the two treatments are not compatible. You will need to exercise a bit of care over this. Bt, that does not mean the Nikwax stuff does not work. Some people love it.
You can also buy various brands of spray-on silicone proofing. Now silicone does make a water-repellent coating, but it is very soft, does not (normally) bond to the fabric, and rubs off easily. It even washes off over time (seriously). It may be of some use on suede street shoes, but my experience with various forms of it is that it lasts about an hour in the rain, then the fabric starts to wet out. Frankly, I do not think it is of any value for bushwalking gear (with one possible exception). Unfortunately, some bushwalking shops do sell silicone sprays. Ignore any recommendations they may make promoting the stuff.
Incidentally, do not try to mix silicone and fluoropolymer either! They will not adhere to each other, and mixing them will wreck any further attempts you might make to coat the fabric. You have been warned! If you do apply a silicone, you could try a couple of vigorous hot soapy washes: that might get the stuff off.
This section focuses on a couple of Atsko products which i have tested, but in fact similar products are available from some other specialist manufacturers. So if you favour another brand which has similar products, that's fine.
Which DWR is best? Well, up until recently none of the after-market DWRs have worked very well for me. However, after I contributed a (favourable) Owner Review on Atsko Sno-Seal to BackpackGearTest (BGT), I was contacted by the VP of Atsko. He was delighted with the Review, and offered samples of their Sports Wash detergent and Permanent Fluoropolymer Water Guard DWR for synthetics. We negotiated, and eventually he sent not only samples to me but agreed to sponsor a full three-person Test at BGT of all their products as well. But there is a twist to this story, and it concerns the Sports Wash.
You might think that the Atsko Sports Wash is just another soap or detergent for the outdoors market. Well, it seems to be a bit more than just that: it is apparently crucial to the success of their DWR treatment. Atsko claim that ordinary washing powders leave a residue on fabric, and that this residue blocks the adhesion of the fluoropolymer to the fabric. The residues include brighteners, perfumes, UV enhancers, and other assorted junk apparently crucial to convincing the consumer that Brand X washing powder is better than Brand Y. With all this stuff on the surface of the fibres, the adhesion of the aftermarket DWR tends to fail. Atsko claim their Sports Wash has been specially designed to leave no residue on the fabric after a rinse or two, and that it really should be used first, before the Permanent Fluoropolymer Water Guard is applied. If you do this and heat-bond the stuff on, Atsko claim their Water Guard will resist up to 25 washings afterwards.
This rang a bell with me. I know, from other experiences, that a silicone-coated Epic fabric will quickly fail if it gets sweaty. That's because the body salts interfere with the surface properties of the bonded silicone coating. It makes sense then that contaminants, especially salts and detergents, might block the bonding of a flouropolymer to the fabric surface. I had noticed that other after-market DWRs I had tried seem to fail after one good downpour: maybe the stuff had never really bonded on? I found it interesting that the Atsko VP was quite adamant about this, and would only sponsor a trial of the Permanent Fluoropolymer Water Guard DWR if the participants used the Sports Wash first. It is also telling that the spray can of Water Guard comes with a little sachet of Sports Wash (inside the cap) and an exhortation to use it first.
Anyhow, we ran a trial of the two products at BGT and I also tried them out. The reactions were extremely good: one tester washed her plain fabric sleeping bag, then sprayed it with Water Guard, activated it as best she could, then cheerfully poured water into hollow in the sleeping bag. Such dedication to gear testing! She reported that some time later the water was still there on the surface of the sleeping bag fabric, in a puddle. When she poured the water off, the sleeping bag was still dry! Bear in mind that this DWR does not cause any loss of breathability to the original plain fabric, and adds negligable weight. If this performance can be sustained for any decent length of time I would have to say it makes far more sense than any Dri-Loft or similar cover. (Note that a Dri-Loft shell can cause quite serious internal condensation problems under cold conditions due to an almost complete lack of real (air-flow) breathability.)
A bottle of Sports Wash contains enough detergent for many many washes and is fairly cheap. The only negative report from the BGT trials was that the Testers generally wished that the can of Water Guard spray held about five times as much liquid: some of them wanted to spray all their gear after their initial experiences!
As noted at the start of this section, some other brands of fluoropolymer DWR might be expected to show similar improved bonding and performance under such cleaner conditions as well.
Now we look at what materials we have for jackets. Long, long ago we had oiled japara jackets as rainwear: they worked - sort of, maybe, sometimes. (Hey: a black oiled japara jacket from NZ was the bees knees in those days! We took them across the Arthur Ranges in South West Tasmania in 1966.) Then we had a brief flirtation with the new PVC-proofed nylon fabrics. This material was more waterproof when new, but sweat condensation inside meant you got very wet if working hard. Unfortunately the early PVC coating process was poor and the proofing layer peeled off quite quickly, after which the thing became absolutely useless. Mine lasted about one year. Into this troubled area came the patented Gore-Tex ® fabric. It was waterproof but breathed out water vapour, and it did not peel. The term 'waterproof/breathable' (WPB) entered the market. Gore had a huge marketing budget, and the material made quite an impression. Here in Australia Gore-Tex took over the whole market for years. Seam-sealed Gore-Tex jackets were the 'only thing' to wear for quite a while.
But after a while some problems surfaced. The thin Teflon ® membrane central to the Gore concept turned out to be very susceptible to damage from our scrub: once punctured by a thorn it leaked for ever more. The ubiquitous thorn scrub around the Blue Mts proved especially hazardous; the Tassie scrub was no better. Once the DWR coating on the outside wore off and the heavy surface fabric got wet, condensation did build up inside and you got wet inside the jacket despite the hilarious "Guaranteed to keep you dry" slogan. For a long time the only Goretex fabrics licensed for use in Australia had a heavy nylon outer layer and a second lighter inner layer to protect the Teflon membrane. The net result was a very heavy fabric. Some customer disillusionment set in. In addition, Gore's licensing conditions were very tight and the jackets proved to be very expensive. In fact, jacket manufacturers overseas switched to other materials fairly quickly, so that Gore-Tex never became dominant overseas as it did in Australia. (Don't believe me? Check some overseas web sites, and see below re Pyrenees.)
Does this mean that the Gore-Tex materials are no good? Not a bit of it. They are superbly engineered fabrics. They are excellent for many things. But the heavy ones generally available in Australia are not a good match for Australian conditions. It is interesting to note that Gore do make very light Gore-Tex fabrics, but for a long time they would not licence them for rainwear in Australia. The official reason they give was that we are too rough on our gear. What this really means is that our scrub is too rough, and they got far too many warranty claims. Understandable.
GoreTex materials are still widely used in Australia, but many other materials are also now being used. The most common is PolyUrethane-proofed nylon. The PU proofing allows water vapour through, although not as quickly as Gore-Tex. (Mind you, manufacturers have wonderful ways of presenting the 'facts' to show each of them has a better product. Just don't believe any of them.) PU-proofed fabrics are usually much lighter and cheaper than Gore-Tex. However, the nylon surface fabrics on all of them are just the same and hold the DWR just the same - no better, no worse. The lighter materials may wear out more quickly, but since the jackets are cheaper this does not matter so much.
Now for the big secret which was apparently unknown in Australia at the time of I first wrote this in 2004. What is the actual waterproof layer in Gore-Tex? It's PU: polyurethane! But, you might say, what about the fabled Teflon layer? Well, it turns out the story is a shade more complex than you think. Some older walkers may remember that there were two versions of Gore-Tex, and that the first version had problems which led to a lot of recalls. The full story is thus. The first version did have an expanded Teflon layer, which blocked the liquid water and let the water vapour through very well. It looked wonderful in the laboratory. But once out in the field it quickly became contaminated from the inside by sweat and body oils. How very sad - and how very obvious in hindsight. So the Gore-Tex designers covered the inner surface of the Teflon membrane with a layer of polyurethane, to keep the oils off. This layer did keep the Teflon layer clean. They modified the PU to be hydrophilic (water loving) so the water molecules could diffuse through it, and they made the PU layer very thin to help with the diffusion. But what really happened was that all the smooth Teflon layer now did was to serve as a support for this thin PU layer. The Teflon part is almost irrelevant to how the coating works. But this double layer does not breathe as well as the original single Teflon layer, not by ,i>any means. Furthermore, the very thin layer of PU has to be protected from damage, hence the use of an inner knit layer and the fact that most Gore-Tex fabrics are 3-layer.
Of course, if PU can breathe, why not skip the Teflon layer and simply use a PU layer? The advantages of doing this are that it bypasses both the Gore-Tex patents and is very much cheaper to produce. The drawback is that a slightly thicker layer of PU is needed when it is put straight onto the fabric. After all, the surface of a woven fabric is not exactly smooth at the microscopic level, and you don't want holes appearing at all the thread cross-overs. Anyhow, many companies leapt into the PU-coating market. The thicker layer of PU meant that a PU-coated fabric did not breathe quite as well as the Gore-Tex fabric, and this allowed Gore to claim they had the best breathability on the market. It became a battle between Gore's advertising budget and the cheaper prices the competion could charge. Gore won the PR battle in Australia for a while, but lost it in most other countries around the world. Anyhow, with all these WP/B fabrics, the surface fabric still gets wet, and you still get cold and wet. The question remains: is all the weight of the 3-layer Gore-Tex fabric worth having? You may gather that the author does not think so. In fact, these days I am quite sure I do not.
Some companies worked hard on improving the breathability of the PU layer, but with limited success. Fancy things like 'Triple Point Ceramic'® are still just PU - in this case with very fine ceramic particles embedded into the PU layer to enhance the breathability. They still could not match Gore. The better approach was to look for a new technology. As a result several interesting developments have occurred recently. The original Gore patents expired, so companies could safely experiment with single-layer Teflon coatings. A company called BHA Technologies developed a Teflon membrane but engineered the surface of the Teflon to be oleophobic: oil-hating, and highly resistant to oily contaminant fouling. It does not need a PU layer to protect it. They call this eVent. Since it is very similar to the original Gore-Tex fabric is it any surprise that it breathes better than the current Gore-Tex? Unfortunately, it is just as expensive as Gore-Tex, and availability is limited. You can't buy it off the shelf. (And the ownership of the patents and brand has changed hands as well.)
There is another development in the arena, by 3M. It's called Propore, and is basicallly a microporous polypropylene fabric. It uses a WP/B microporous polypropylene membrane which is laminated to a single nonwoven polypropylene fabric or laminated between two non-woven polypropylene fabrics. Here we leave the traditional concept of woven fabrics and leap into a whole new technology. Different from layers of PU, Propore breathes equally well at low and high humidity levels, and breathes better than the Gore-Tex membrane. Unlike eVent and Gore-Tex the technology used in Propore is very cheap, and the fabric is very light. It is even lighter and less expensive than PU fabrics. A Propore jacket can weigh 133 g and cost only US$30! Propore is becoming a cult choice of long distance hikers - at least in America where they hike on trails. The disadvantage it suffers is that it is not as strong as nylon fabric. Another very similar fabric is used by Frogg Toggs, and is reputed to be a little stronger. Also available in America is a range of 'fabrics' called Tyvek: they too are synthetic non-wovens, and waterproof/breathable.
Another recent fabric is Entrant G2 XT from Toray. It is supposed to be more breathable than Gore-Tex but not quite as good as eVENT. It uses a hydrophobic micro-porous membrane. Apparently it has some penetration into the European market, but not so much into the USA market. I know the Toray company: they make very fine fabrics, so this one bears watching.
Finally, there is a new development in totally waterproof fabrics which are not breathable, called 'silnylon'. Part of the logic here is that no shell keeps you dry in bad weather anyhow, so why worry about that: just keep the wind and fresh water off your skin at the minimum weight. But the double-coated (both sides) fabric has far greater advantages than just waterproofness: it is also much stronger than PU-coated nylon of similar weight. Silnylon is quite wonderful stuff, and is also mentioned below under alternate designs and materials and in the DIY section.
Sadly, I have to report that the early and very good versions of silnylon, with a 'wet-look' finish, are no longer available. That stuff had a pressure-rating of over 70 kPa: seriously waterproof. The coating plant in America ran into trouble with the EPA over the emissions, and rather than fix the problem management just closed the line down. The current stuff has a dry-look finish and is made principally for the parachute market and the blow-up wriggling advertising sign market. The coating process has gone steadily downhill since. The fabric is still very strong - stronger than plain coated nylon, but the pressure rating has dropped to about 15 kPa. That's enough for the major markets you see. What this means is that the modern silnylon can leak slightly when used as rainwear (eg at the shoulders), although it is still very good as a tent fly.
There are sources in China which are producing both double-coated silnylon and silicone/PU coated fabric. The latter is a very interesting development: the PU coating is much more waterproof than the silicone. And a PU coating can be seam-sealed with conventional tapes. However, finding a supplier in China is not that easy, and finding one who will sell less than 1,000 m at a time has not yet been possible.
There have been some passionate arguments about whether one should use anything but the absolute best material in the mountains, in the name of 'safety'. This begs the question of what is 'best' of course. Just don't believe anyone when they try to tell you that you will die if you don't take an XYZ jacket (where XYZ is usually an expensive GoreTex product). I have actually been told this most earnestly, even passionately. But the truth is that many of us (the older ones!) survived for years before XYZ jackets were even invented. I suspect some people hold this attitude to justify having just spent $400+ on a jacket which they subsequently find is less than perfect.
Despite all the criticisms above, Australian bushwalking jackets are some of the better designed ones in the world - as jackets go for Australian needs. If you compare Australian designs with those from overseas you will notice two major differences. Ours are much longer, and overseas ones often have a lining. There are reasons.
Australian parkas are made for (relatively) warm rain in the bush; overseas ones are often made for dry snow in the mountains. That means ours can or should be longer, hopefully to keep our bums dry: the length would get in the way on overseas mountains. At the same time, there is no point in having a lining when you are going to be hot inside your jacket anyhow. Less obviously, we have traditionally thought that ours need to be a bit more waterproof. However, since we never stay dry in serious rain, one has to wonder about this requirement.
Some key points to look for in a traditional bushwalking parka are therefore as follows. A long jacket is useful when walking: it keeps your backside and waist drier (note: I did not say "dry"). A cord around the waist is essential: it stops the wind whistling up inside when it is really cold. A cord around the bottom edge is useless: when you are walking it can't work as you need the room to move your legs. Long sleeves are good; you can bring your hands right inside the sleeve and keep them, if not dry, at least out of the wind. A Velcro ™ strap around the wrist is best; elastic doesn't work except with the very lightest of fabrics.
The zip down the front does not have to reach the bottom of the jacket. In fact, if the jacket is long you will probably unzip it a bit from the bottom to give your legs room to move. This can be essential if you are climbing through rough country. So if the jacket is long the zip has to be double-ended; shorter jackets may not unzip all the way down, but this may make them hotter. It is best if the zip has a good storm flap over it, otherwise the rain will come straight through the zipper. A 'storm flap' consists of an outer flap going over an inner flap from the other side, with the inner flap being bigger than it needs so the end folds over, and these do work better than a single flap. This is shown in the diagram to the right. There are two ways of securing the storm flap over the zip: press-studs or another zip. The advantage of the press-studs is that when it is very hot you can skip the zip and just use a couple of studs to keep the jacket partly closed. This happens more often than you might think, and you can't do this with a second zip. The zipper pull-tab should have a good bit of tape on it so you can find it easily, especially with gloves on. You can always add a bit if there is none. The zipper should be robust: there is a terrible tendency to give it a good tug when conditions are bad. A moulded-tooth zip (as opposed to a coil-coil zip) is probably better unless you are willing to be a little careful. That said, there is no reason why a lightweight parka should not have a light #3 coil zip: it will work just as well (as the author has proven over time).
A large well-shaped hood is essential. If the hood is too small for you when you try the jacket on, it is going to be even worse when you put a pack on. The shoulder straps will pull the hood down on your head. Check this very carefully! Also check what shape the hood makes when the draw-cord is pulled tight. Some hood openings do not seem to be where your eyes are, or they make it impossible to turn your head sideways. This gets worse when you wear glasses. A good hood has a bit coming up under the neck like a tube and over your chin. This may sound (and look) funny at first, but wait until you are walking through driving sleet or snow before deciding. A bit of a peak extending forward of the drawcord is useful too, to stop the rain from streaming down across your face. It doesn't have to be very large: your face is going to get wet anyhow.
When you put a jacket on try raising your arms to the roof. The jacket will inevitably ride up around your waist, but the less movement the better. This is achieved by a large gusset under the armpit. Cheap designs don't have this: skip them. Of course, when you lower your arms this may leave a whole lot of excess loose material under your armpits. Frankly, who cares? Unless you want the jacket as a fashion item, in which case you don't need to read this. At the same time, check the wrists don't ride up your arms: if they move at all the sleeves are too short.
Some reinforcement over the shoulders may be useful, but it adds weight. This is to resist wear from the shoulder straps of your pack and to resist water being forced through the fabric. In general this dates back to the days of oiled japara and one can worry too much about it. But do check where the seams are: you don't want any over your collar bones, for obvious reasons of comfort.
It may help to have one or two external pockets: you would be surprised how useful they can be at times. That said, unless they have an extremely good cover the pockets are going to fill up with water: what do you have which can be left floating? A small drain hole in the stitching at the bottom is recommended and often provided. An internal pocket at chest level for a map is one of the more useful features to look for. It is usually accessed from behind the storm flap but in front of the zip.
"Pit zips" are sometimes offered under the armpits "to let the hot air out". If I am that hot I have to open more than a pit zip; otherwise I would prefer to keep some of that hot air inside to keep my skin dry thank you. Pit zips are a bit of a gimmick in my opinion as they don't work very well in practice. They leak, and they add cost and weight. They seem to belong in the "marketing features" category, along with huge numbers of pockets, reflective tape, etc. Forget them.
Finally, all seams above the bottom hem should be 'seam-sealed' one way or another. The normal way is with a seam-seal tape applied on the inside. This can add some stiffness to the design; it does add cost. However, in this case the cost is absolutely worthwhile: without sealed seams the jacket is almost useless.
Details like how many pockets there are, reflector tape, fancy logos and so on can be left to the street fashion crew to worry about. They just add cost and weight.
Not all walkers bother with these, but if you are going into Alpine areas they are strongly recommended at all times of the year. The number of times Boxing Day on the Main Range in Kosciusko NP has been celebrated with sleet and snow is startling. Cold, wet and miserable is no fun.
That much said, we are left with the question of what sort of over-trousers are needed. For this exercise we can divide them into two opposing classes: heavy, expensive (and typically Gore-Tex) ones with zips down the sides, and very light ones. The advantage of the zipper ones is that you can get them on over big boots fairly quickly. Unfortunately, that is their only advantage, and who wears big boots? They are much heavier, much bulkier, much dearer, and just as prone to damage as the light PU/nylon ones. Some of the light PU/nylon ones are very wide in the leg, so you can get quite large footwear through them. Of course, if you are not wearing boots, the whole thing gets much easier.
The light overtrousers can be broken into two sub-classes: totally waterproof and 'breathable'. The lightweight totally waterproof ones are usually made with PU-coated nylon. The obvious question is will they last? Well, if you wear them in thick scrub you are asking for damage, but the same applies to jackets. What is surprising is how well they do survive: the wet nylon surface seems to skid off most sticks very easily (but barbed wire is a no-no). And they can be great fun in the winter: they can slide really well on snow and ice. Great for parka-sledding, but sometimes a little exciting when you fall over on a steep slope. Our light PU-nylon ones have lasted for years, despite numerous scrub-bashings and slides down icy snowy slopes.
Should they go on the inside or the outside of gaiters? Well, if you put them on the inside they are protected from the ankle-level scrub, but then they funnel the water straight into your footwear. On the other hand, if it is pouring rain, your feet will probably get wet anyhow. Your choice (does it matter?).
The 'breathable' class is covered next, and is rather interesting.
For historical reasons Australian walkers all have parkas, but are they really necessary? When people went walking with all-cotton clothing, the answer was probably yes. Cotton gets wet and stays wet and cold: this can be dangerous. But what if you are wearing a DWR-treated nylon top (or windshirt) and a thermal under it, while walking energetically? It turns out that you can stay reasonably warm without a parka under quite significant rain, for the reasons outlined above. Get moving and stay hot, and you drive the water off. OK, you will get a bit wet at the wrists and neck - but you would have got equally wet there with a parka on most days anyhow. The key point is that when you stop you put your waterproof parka on very quickly.
This method does get used overseas a bit, and we have tried it in NSW and the French Pyrenees with success. But it requires some judgement, lots of experience, lots of good food and spare dry clothing for the end of the day. You try it at your own risk - and not in a howling gale or sleet! But, it does work.
It is interesting that one fabric in this class sometimes used in Europe, and especially the UK, is 'Ventile'. This is a remarkable fabric based on cotton of all things! But it is a special form of tightly woven cotton which has not been stripped bare of its water-repellant properties, and it has an interesting history. It was developed during World War II for use in making waterproof (but breathable) suits for aircrew: it could keep them alive if they were shot down in the bitter North Sea. It is not widely available, but it is still made by one .
Finally I should mention that there are a few rather specialised synthetic fabrics available in America which do not have a membrane at all. Instead they rely on a tight weave and a good DWR. For example, the extremely light GoLite Whims overpants (shown above) are made of a carbon fibre and polyester fabric with a good DWR, and we found them adequate in the European Alps in heavy rain and even in the snow. Yes, our knees did get damp when the Whims fabric wetted through (it was bucketing down rather seriously at the time), but we kept walking and as soon as the rain stopped the fabric (and our trousers inside) dried out. I think 'waterproof' trousers might have left us with wet trousers for far longer.
This is a generic term (already) for the concept roughly outlined above, although not all companies using the term agree exactly on what it means. One version goes like this: you take a very water-repellent surface fabric and combine it with an insulating bulk layer on the inside to create a fabric which breathes but is 'sort-of waterproof'. Some companies want the fabric to be a stretch fabric as well, but imho that is optional (and very expensive) at this stage. Other companies argue it should mean just the surface fabric, and that the user should be free to decide what insulating layer to have on the inside. I incline to the latter. The archetypical brands here are Epic by Nextec and Schoeller fabrics.
More recently the fashion industry has got into the act and, once again, corrupted the whole market place. Recent trends (2006) have been for many companies to use the term 'soft-shell' to simply mean 'stretchy', with little or no regard to whether the fabric is waterproof, water-repellent, breathable or whatever. Be very careful when encountering the term in marketing spin.
The advantage of the integrated multi-layer approach is that it produces a very nice garment with nice outside surface and a soft warm inner surface: very consumer-acceptable. Think trekkers and street wear here. The disadvantages (to the bushwalker) are several: higher price, higher bulk, less flexibility. You can't easily change the weight of the insulating layer and you can't change that layer if it does get damp. It is not my choice for Australian conditions, although I note it has some deserved popularity in places like the UK.
The advantages of the single-layer approach for the bushwalker are obvious: lower cost, more flexibility, less bulk if you want to have just a jacket for emergencies tucked into your pack. The realities are that the market has room for both. The author cribbed a good review of the whole soft shell concept in 2004; it seems to have been removed from the web since then so the guts are reproduced here.
A very exciting development associated with the Soft Shell concept is the use of silicone impregnation methods applied to the fibres themselves. This is completely different from the old spray-on silicone treatment. Typical base material is nylon or polyester fabric which has been thoroughly impregnated or encapsulated in a silicone polymer. The result is a DWR in bulk, and one which does not wear off. The water just beads off - and so doesn't get through. Two sources of such materials are the Epic range by Nextec, as mentioned above, and the knitted Schoeller fabrics. Both are attracting considerable attention - and high prices.
I used some very light synthetic Epic fabric called Malibu to make a nice soft-shell ski jacket, good in the wind and snow and tolerable under pouring rain when I had a good inner layer under it (and was working hard). I sealed the (double-stitched) seams with a special tape which adheres to the silicone coating, but in hindsight I am not sure this was really necessary. A good drenching of the stitching with a silicone spray might have worked just as well. I have successfully used this jacket for several years now for snow trips.
I also experimented with a poly-cotton version of one of the Epic shell fabrics by making a wind-shell out of it. My reasoning was that it might work better than talsn fabric in light rain, meaning I could skip wearing any rainwear. The result was distinctly not encouraging. OK, it was a failure. The poly-cotton fabric got wet because my sweat nullified the silicone coating, and I suspect the coating was abraded off the cotton fibres as well. Bluntly, cotton is not a good choice here, in any combination, and getting sweat on the Epic fabric is not a good idea either.
At one stage Macpac was using some synthetic Epic fabrics in some very light jackets, but without seam sealing and with only a single line of stitching at the seam. It would seem they do not intend these for any form of serious rain protection, just for wind protection. An interesting concept, and pity they didn't double-sew the seams imho. The Epic material does breathe a bit since it does not have a continuous film across the face of the fabric, and could be quite good under the right conditions. This is a Work In Progress: see the Ultralightweight and DIY areas for more information.
A very exciting development has been the introduction of what is called 'silnylon'. This ia made by coating both sides of a very light parachute fabric with a silicone polymer. The polymer soaks right into the fabric, encapsulating the whole weave. Really, callling it a 'coating' is quite misleading. think of it rather as a fabric-reinforced sheet of silicone polymer.
There are several variants on this theme. The classic one uses a soft silicone polymer which cures to a slightly 'grippy' surface, and is highly waterproof. It is called silnylon.
Another variant is used by the yachting industry to make spinnakers. For this they are mainly concerned with non-stretch stiffness and a lack of water absorption. Note carefully that actual waterproofness is not a requirement here. I believe the silicone polymer is sometimes blended with a polycarbonate for this to get the stiffness required. This works while new, but the result can be a bit noisy in the wind and the creases have tended to leak after a while. That said, some of these fabrics are very light.
But "SilNylon" (or variants thereof) and some stiffer siliconised yachting fabrics are different from this, and started out totally waterproof. The 'silnylon' is making big waves in some areas like lightweight tents. Look for some of these fabrics to reach the Australian market soon. ([2010: no sources known in Australia.]
The author is experimenting with some imported samples of these materials. The Malibu was good for a shell jacket, and the original Silnylon made superb lightweight and waterproof tents. It is not too bad as a poncho (next) either, as long as the poncho can flap a bit to reduce condensation. However, as noted above, the latest versions of silnylon are a bit of a dissappointment. I gather some gear manufacturers in America are now having job lots made to their specifications in China, but few will sell the fabric.
Once upon a time we didn't have parkas: we used ex-army ponchos. These are not a lot of use in really thick scrub or on ridge-tops in a high wind, but they weren't too bad on a track in the forest. They left your arms free and didn't cause too much sweat build-up. They could be put over your pack as well, removing the need for a rain cover. But we seem to have forgotten all about them, what with our Gore-Tex parka love affair.
We spent 6 weeks in the French Pyrenees in the "summer" of 2002. Actually, it was the worst summer for the last 50 years, and it rained a lot - almost every day. What startled us was that very few of the French walkers we met carried parkas in the summer. But they ALL carried ponchos or capes. These ranged from fairly sophisticated upmarket affairs to simple PVC designs.
To be technical: a poncho is a flat piece of material with a hood set into the middle. You throw the lot over yourself and your pack, and you head pops through the hole in the middle and is sheltered by the hood. There are studs or ties down both sides to hold it together in case of wind. This piece of material is quite wide: big enough to rig an emergency shelter out of in fact. It is also wide enough to shelter most of your arms even when you are using them. Some Americans like them too: part of the tarp-tent craze there.
A cape is a bit like a poncho, but tailored and sewn down the sides. It has real sleeves, although they may be fairly generous. Obviously it offers a bit more shelter under high wind conditions. Conversly, in warm weather you will get a bit more sweaty inside one, although not as sweaty as inside a parka. And it can't be used as an emergency shelter very easily. However, there is no reason why you can't put a front zip into a cape: then it looks a bit like a parke for a hunchback! But it is so easy to put on when a shower happens: you can do so while walking along.
Obviously, you wouldn't use either of these when ice climbing. They may not be all that good for ski-touring either. But we found they were wonderful for track walking. Putting our parkas and pack covers on was an absolute pain in comparison. And they worked. In fact, I am not sure all of the ones we saw in France were really fully waterproof: just water-repellent in some cases.
In 2007 wmy wife and I took our ponchos to France for 3 months, doing the GR7 and the GR5 tracks. Going around Mont Blanc we ran into some unseasonal weather - a significant amount of snow in mid-summer. The photo to the left is at the Col de Bresson: a howliong gale which turned into a snow storm as we crossed over. The photo to the right is the Col de Bonhomme: even more snow. In each case we were quite warm and happy under our ponchos. They trapped warm air inside and kept the windf out.
John Walker contributed the following comments:
Recently however I've taken to using a $2 shop vinyl poncho (not the pocket sized ones, but the "heavy duty" type, if you can call them that). This was an experiment but has been surprisingly successful for the type of walking we do (day walks, mostly on track...various standards from fire trails to overgrown, almost non-existent footpads). I would not call it a robust long term solution, already a few holes and tears from overhanging scrub but still serviceable after several uses (and abuses). When it finally gets torn to shreds I'll just buy another one.
- real cheap
- extremely lightweight
- relatively sweat-free (the big holes where your arms and legs go through help with ventilation I suspect)
- covers your pack as well (NB I'm talking 30-35 litre day packs though)
- seems to actually keep you reasonably dry
- very fast to deploy over self and pack
- could be longer, especially at the back
- heavier duty material would make it more robust/tearproof
A rather kinky idea, which should work really well for some people, is the 'Packa'. Think of a conventional pack cover and a parka joined together at the edge of the pack cover. Tie this onto the pack as a pack cover. When it rains, reach back, grap the parka bit, and pull it around you. Alternately, think of it as a snug, well-fitting poncho. The current model is made from silnylon and is rather light.
Both the Packa and a poncho have several hidden advantages too, apart from sheer convenience. The first is that your back can sweat into the pack frame space rather than having that waterproof layer smack up against it. The second is that you won't get leaks into your pack from the stitching in the harness area, and the harness stays dry. With a conventional pack cover a lot of water gets funneled down through the harness, and can get into your pack. The major drawback is of course the fact that when you and your pack part company, one of you will be without rain protection. If this is unlikely to matter, something like this or a well-fitting poncho might suit. They do make it very easy to pull on rainwear without stopping.
I tried out a silnylon poncho/parka cross (rather like a Packa) I had made myself on our trip in the Pyrenees in 2004. If had a full-length opening down the front and I had designed it so that it was easy to slip my arms in and out of the sleeves. While it did not rain very much, the ease of use was wonderful, and the ability to alter the ventilation really worked well. I have since converted to using this poncho/parke all the time: it works!
We list here some well-known brands. All brands have "waterproof" models, at least as long as you pick the ones with seam sealing. Some brands also have 'softshells' which are not totally waterproof, but which do have uses.
Well respected brand, usually long and simple.
Good Australian company
OK, but tend to be a bit fashion-oriented with frills
Solid products, but never very light
Good brand, many models, some light-weight stuff
UK firm, extremely light-weight, very low cost, last well. These are popular with ultra-lightweight enthusiasts. Their main weakness lies in their having a single flap over the zip rather than a full storm flap, and this does allow a little bit of a leak in very bad weather. Available via their web site www.peterstorm.com which now has a web sales section. At the risk of quoting models, I have used:
120 jacket: 300 gm, mid-length, PU Nylon
122 trousers: 150 gm, no zip, PU nylon
139 jacket: ? gm, longer, PU nylon
Asian origin, huge range, also light and low-cost. Some models are seam sealed and "waterproof breathable", but others are not breathable. They are almost as light as the Peter Storm, and can be bought locally.
We have one of their jackets, and it is a bit heavy, but very rugged!
NZ firm, judged OK by many when on 1/2 price sale (a harsh judgement). Also carries Mountain Hard Wear. They do emphasis the 'street wear' and overseas trekking side a bit more, so fair enough.
Well respected NZ firm, a little more oriented towards alpine designs. It has been through the wars recently.
© Roger Caffin 1/May/2002, 16/Feb/2010