The Great Debate: Waterproof vs Breathable (Wintertime)

It’s funny how coincidences happen. I’d been thinking about posting something on this subject for a week or two, but clearly failed to get round to it. Then, a few days ago, the subject came up in a big way on a couple of other outdoor blogs.

Alan Sloman brought the topic to the fore in his blog “On Being Warm & Dry” where he discusses the merits of Paramo gear and keeping the weather at bay on even the most horrendous of days, such as we have seen recently here. Many outdoor enthusiasts had recently experienced a particularly rough weekend in the Yorkshire Dales, so it was fairly a topical discussion, too. Needless to say, the post elicited a huge mailbag of comments on the subject.

Another commentator, Alan Rayner (of A Blog On The Landscape), put his own thoughts down on the issue in his post “Waterproof Hiking Coat” (here) where he discusses the contradiction in searching for a garment that is both 100% waterproof and 100% breathable. Both articles are well worth a read.

So, ever keen (and unashamed!) to jump on a bandwagon, here are a few of my own thoughts.

Layering & Breathability

Based upon a couple of comments in earlier threads, I had already put the feelers out for a bit of feedback on one of the walking forums (here) to get some idea of the opinions and experiences of regular walkers of all types, but coming at it from a slightly different angle – that of layering.

I was beginning to wonder whether there may be a little confusion developing between the terms layering and breathability and the part each might play in the ability to control our temperature and wear climate in strenuous conditions.

In simple terms, Layering describes the use of various clothing layers to perform different functions in regulating your temperature and protecting you from the elements. Typically, this takes the form of a wicking base layer to move sweat away from the skin, a mid layer (or layers) for insulation purposes and an outer layer for protection against the elements. Breathability describes the layers’ subsequent ability to deal with the build up of that sweat.

Having said that, breathability alone will not compensate for wearing too many layers – often, layers have to added or subtracted to get the right combination for the prevailing conditions.

In Winter Conditions

It may at first seem counterintuitive, but winter is often the most testing time for gear – not just in terms of keeping the elements out, but also in respect of being able to moderate one’s temperature and, in particular, maintain breathability.

Even in wintertime you can get hot as you walk, and your body’s natural reaction to this overheating is to produce perspiration. In warm climates, this cools on the skin to help regulate body temperature. The trouble is this also happens when you work hard in cold conditions too, so sweat needs to be shifted away from the skin (to prevent over-cooling) in a process known as wicking. Wicking fabrics are always recommended for next-to-the-skin use as non-wicking materials (such as cotton) simply hold the moisture next to the skin, again resulting in over-cooling.

Next, sweat is moved through a (usually relatively) porous but insulating mid layer, such as fleece, to reach the outer protective layer and thence be transferred to the outside. However, this is where it hits a problem – the outer layer is supposed to keep the rain out from the other side! So how can a fabric let sweat out from the inside, but not let rain in from the outside? This is where a careful balancing is needed, and where the “Waterproof vs Breathable” debate really gets going.

Waterproof Fabrics

Broadly speaking there are two types of waterproof*, breathable fabric systems. First is what I will refer to as the Paramo-type of directional clothing system** (as they refer to it themselves) that claims to mimic animal fur and makes use of Nikwax Analogy technology. The second is the waterproof membrane type system exemplified by Gore-tex fabrics.

*The term waterproof suggests an absolute ie: it keeps water out full stop. While this seems a reasonable assumption on the part of  the consumer (up to a point), from the manufacturers perspective it means something different, and the term as far as they are concerned more accurately covers a span of “water resistance” determined by the ability of water to penetrate the fabric under pressure.

This is usually referred to as the hydrostatic head – and classified by how many millimetres high a column of water needs to be to force it’s way through the fabric. My understanding is that a hydrostatic head of 10,000mm is the benchmark for waterproof fabrics suitable for reliable waterproof performance in outdoor clothing.

So, as you can see, this is not an absolute. It could be improved, say to 20,000mm or more, but often criteria such as weight and/or cost and/or breathability, etc, outweigh the benefit of extra waterproofing. Well, mostly, that is.

**If what I have read is true, Paramo Nikwax Analogy fabric does not meet that 10,000mm hydrostatic head benchmark, however the technology has been lab tested and shown to repel heavy rain for several hours.

I am using “Paramo” and “Gore-tex” as generic terms for now, as there are many other “own brand” fabrics available that are as good, if not better, than the two brands mentioned above. For example, other Paramo-type systems are supplied by the likes of Furtech and Cioch whilst Gore-tex-type waterproof membranes include such fabrics as eVent, Berghaus AQ2, Aquadry, Marmot Membrane and Haglofs Proof, to name but a few. All of these have their own unique features and performance characteristics, but work in a broadly similar fashion.

Of course, each technology has it’s own strengths and weaknesses. In general terms these are perceived to be:

Paramo-type:

Pros: Quiet, comfortable, soft fabrics; good breathability; shouldn’t leak badly if pierced; robust.

Cons: Often quite heavy; can be over-warm, especially outside winter; need washing/treating regularly; can fail catastrophically, especially if the fabric is contaminated; pressure (eg: sitting down) can force water through the fabric.

Gore-tex-type:

Pros: Lighter weight; require less washing/reproofing; can be robust; several different versions – should be one to suit.

Cons: Noisy and rustly fabric; often only partially breathable; moisture can build internally; can leak; can tear.

Of course, this is not a complete list, and there are some sweeping generalisations in there (not least because there are several type of Gore-tex branded membrane fabrics alone, each with differing characteristics and pitched at differing price points).

Technology

There is quite a bit of science involved across the various technologies, brands and qualities. For the sake of simplicity, I want to steer clear of that as much as possible. However, for the scientists amongst you, most manufacturers’ websites go into some detail about the technical characteristics of their fabrics if you wish to delve further into that aspect.

But essentially it boils down to this: in both cases the base and/or mid layers move perspiration away from the skin towards the outer layer where it is dealt with by the shell.

In the case of Paramo-type products, the shell takes the form of a bi-laminate breathable fabric that is not completely waterproof, but whose waterproof qualities are enhanced by a proofing application to repel the rain such as Nikwax. Sweat is driven out through the semi-porous fabric whilst a combination of the fabric and the added proofing agent keeps any rain out. The proofing agent prevents the outer part of the laminate from wetting out so that the “pump action” of the inner part of the laminate is maintained. Remember, this is the simple version!

In the case of membrane technology, shell fabrics usually incorporate a microporous membrane sandwiched between an inner laminate and a robust outer face fabric that is often treated with a DWR coating. Warm perspiration vapour can pass through the tiny pores, but raindrops are too large to pass the other way. Coupled with the DWR coating, this is what keeps the rain at bay. However, it does also mean that liquid perspiration cannot pass through the microporous membrane, which is why such fabrics are considered less breathable than a Paramo-type fabric.

The Problem In Winter

The crux of the problem, though, is this. Both versions work best to remove perspiration build-up when the outer is dry. The trouble is, you tend to need your waterproof outer shell when it is raining.

If the rain is quite light and the duration short, it usually presents no problem. But in prolonged, heavy rain, the outer can become waterlogged (a condition referred to as “wetting out”) and sweat dispersal from inside is then seriously compromised. Once the outer is overwhelmed, it results in an accumulation of moisture on the inside of the jacket, causing the base and mid layers to wet out and produce the over-cooling effect we are trying so desperately to avoid.

This is exactly the type of situation faced in winter – rain, snow and cold work against your jacket’s ability to breathe!

Another factor that can affect the situation is this. The outer water repellent application will cause rain to bead and run off quite well at first, preventing wetting out from occurring. But, as the jacket is used, water repellence is gradually reduced as the coating is worn away through continual folding of the fabric or by abrasion, for example through contact with rucksack straps and hip-belts. Reproofing will correct this, at least for a while.

And The Winner Is ….. ?

So, is there a clear winner between these two systems?

Well, no, not really. The Paramo-type system is generally regarded as better for breathability, and when working well probably deals with sweat better than a membrane can, keeping the wearer warm and dry. The combination of outer fabric and Nikwax proofer can effectively keep rain out too.

But regular users tell me there are problems associated with this type of system.

First, under pressure – for example when sitting down, leaning on an elbow, under waterlogged rucksack straps, or in heavy rain driven by high winds – water can be forced through the fabric. The water pressure overwhelms the fabric’s ability to pump water out from inside.

Second, contamination of the fabric (say from a detergent cleaner – remember this for later!) can lead to the Nikwax not taking properly, and when this happens the proofing fails and water pours in – your protection, particularly when the water is pressurised, is effectively totally lost.

Which is a problem. Although the fabric also has some windproof properties, getting wet and cold can lead to a crucial loss of energy and, in severe cases, the onset of hypothermia.

The general guidance for cleaning this type of garment is:

1. Run the washing machine with just water to clean out any remaining detergent from the system, especially in the powder drawer.

2. Repeat if you are not sure.

3. Having ensured the machine is scrupulously clean, wash the garment in a recommended cleaner such as Nikwax Tech Wash or pure soap flakes.

4. Run the machine yet again to wash the garment in Nikwax reproofer (eg: TX Direct).

5. Tumble dry on a low heat to activate the water repellence.

6. Do this around 4 – 6 times a year.

7. As a precursor to all of this, some users (not Paramo themselves, as I understand it – do not take this as a recommendation!) wash their Paramo in detergent (remember, a suggested contaminant to be avoided!) to completely remove all traces of old proofer first, then start at point 1.

What a faff!

In the opposite corner, the Gore-tex-type membranes are generally regarded as less breathable – less able to handle the build-up of perspiration, and consequently can feel clammy against the skin – noisier and less flexible (so less comfortable to wear, according to some). They can also tear and, in extreme situations, they can leak too. And, if they do lose proofing and wet out on the outside, the already lower breathability will be reduced further, worsening the wear climate.

On the plus side, they require much less in the way of reproofing, are more easily cleaned, and often produce lighter weight, less over-warm garments. The DWR treatment generally lasts a lot longer before reproofing is needed, and the fabrics are (in most cases) more inherently water resistant if the DWR wears off.

As mentioned earlier, there are lots of different membrane fabrics, including the newer generation of more breathable, stretch waterproof fabrics, so the points I am making about them are somewhat general. However, fabrics such as eVent are regarded as being amongst the most breathable of membranes available, combating one of the main downsides of this type of technology.

It Looks Like A Tie: What Happens Next?

So, what is the solution? Well, I’m sure you’ll all be surprised to hear, there isn’t a definitive answer! In this situation, one size doesn’t necessarily fit all.

Bearing in mind we are considering specifically winter conditions, it is important to try to get that perfect blend of weatherproof and breathable – or at least to achieve the most acceptable balance between the two and which is most suited to one’s individual needs.

My Preference

For me (and this is my own, personal view – nothing else) I feel I would not want to run the risk of a complete waterproofing failure at a crucial time. Also, I am not inclined to spend a lot of time over the care/aftercare of the garment – Life’s too short, as they say – and, if you get a leak mid trip, having to reproof along the way is quite inconvenient, if not impossible.

So I have always gone down the membrane route.

I prefer a pretty “bombproof” garment too, and am happy to choose something a little heavier if I see it being tough, warm and proof against the elements – without being melodramatic, one day your life may depend on it. I also like to know, in the case of “failure”, that the membrane will keep the rain out to an extent even if it is not working properly or is compromised in some way. I can’t handle being soaked through, but I can manage being a bit damp!

Having forked out for a garment, I want it to last well, too - I am looking for a 5 to 10 year life expectancy, even under occasionally tough conditions and fairly heavy wear. In this respect I am also slightly mistrustful of the current crop of seemingly flimsy, lightweight offerings that may do what they say well enough for now, but what about long-term performance?

I’m sure I’m not the only one who questions whether we have reached the workable limits of the lightweight concept without compromising performance?

For information, I own a Rab Bergen jacket – by all accounts, and in my own experience so far, a fine jacket which I like a lot. It is quite lightweight (in grams) but it also seems possibly a bit lightweight in protection. Time will tell. I am happy to use it in the shoulder seasons, even if the forecast is not great.

But would I put my faith in it, knowing I was going to experience some unpleasant winter conditions? Not without leaning more about its capabilities in poor weather first, that’s for sure. I consider protection to be more important than sheer weight in such circumstances, and my current winter jacket of choice is an old Lowe Alpine Gore-tex model (whose name I can’t remember!) – a bit of a beast, but which has never let me down.

Conclusions

Of course, as always, it is a matter of personal opinion. What works for one, won’t necessarily work for someone else. We all have different opinions of what is acceptable in terms of the amount of care/aftercare needed, how breathable we really need a garment to be, how uncomfortable we can cope with, how hot we run, how wet or cold we will accept being, our own experiences and those of others we know.

Also, we all have different perspectives. Daywalker, LDPer, backpacker, mountaineer, fell-runner, lowland walker – all will have a slightly different view as to what constitutes the perfect jacket, depending on what best suits their needs.

Without trying to sound too yucky, I consider that I run quite hot and perspire a fair bit when walking. This does sometime lead to a build-up of moisture inside the jacket but, with a good wicking base layer, I find I don’t get cold, and have no problem in accepting a bit of a warm fug inside my clothing – the discomfort, for me, is not too great. I just want to keep the weather out.

Thinking back, when I was young we either had the choice of an old-fashioned anorak that soaked up the rain, or a racy new cagoul in which we slowly poached. Pleasant it was not. Having said that, in days of yore, walkers and mountaineers went out in tweed, wool and cotton – all sorts of unmentionable clothes that we wouldn’t be seen dead in these days (possibly literally!). Compared to those days, what I grew up with was luxury, and nowadays a little discomfort seems a small price to pay for the much-improved protection on offer.

Others, of course, may not find this state of affairs quite as acceptable, and demand more of their clothing.

My own view is that expecting to keep completely dry both from the outside and the inside when working hard (particularly in winter) is essentially unachievable, since the two problems are diametrically opposed – breathability requires the shell to be permeable in some way, whilst waterproofing prefers the shell to be more impermeable. The two attributes are working against each other – can anything breathable be FULLY waterproof, or vice versa?

I can’t say I know the answer, or even if there is an answer at all. But I do know that there is no miracle solution, and whatever you choose there is bound to be an element of compromise – the skill is finding the best blend of attributes for you.

And I also know, whatever the conclusion is, it’s fun considering it!