“My Jacket is not waterproof, it leaks!”

So came the complaint. “I have paid a lot of money for this and expect that it keeps me dry while running on our trails”.

I work for the Adventure Inc, the distributor of Mountain Equipment and Ronhill among several other leading brands. Every winter I get at least one complaint like this. Here is how I explain what are possible contributing factors to this situation.

The Summary:

  • Decide very carefully if you indeed need to wear a Waterproof Breathable Jacket or if a shower proof jacket will do.
  • When you exercise you produce more sweat than any Waterproof Breathable jacket can handle. So if you are exercising in a Waterproof Breathable Jacket you are going to get wet from the INSIDE.
  • You have two choices: you can either slow down your rate of exercise (slow down running or start walking or stop walking altogether) or you can deal with the moisture build up INSIDE your jacket.
  • Option 1 is not always feasible when running a race. Option 2 is ok as long as cold does not become a problem.


    waterproof jacket showing the membrane (white) on the inside of the jacket.

The Theory:

Waterproof Breathable Jackets should all be made out of some type of membrane or laminate. This prevents water coming INTO the jacket form the outside (waterproof) and allows water vapour OUT (breathable). (It has got nothing to do with being able to breathe through a jacket.) This magic layer actually works in conjunction with the rest of the jacket’s layers in order to produce the best performance. The membrane will only work if the outer fabric is dry. Check out my post one why this is important here. Also the membrane works best if not in direct contact with your skin.

If all these conditions are met then we can measure the theoretical breathability of the fabric. (Note we are talking about the fabric breathability and not the jacket’s breathability. We will get to that later.) When you start exercising, irrespective of which brand of membrane you choose your body will produce more moisture (in the form of sweat) than the membrane is able to deal with. So now you have a problem. What happens is that you build up heat and moisture on the inside of your jacket. This in itself is not an issue as long as you are able to continue moving at the same pace. ie if you slow down you will produce less heat, your wet layers will cool you down and you will feel the COLD! This is much more pronounced when you are wet rather than dry.

Waterproof Breathable membranes don’t work by themselves: They need a differential of temperature, pressure and moisture to work best. In other words the hotter and sweatier you are on the inside of your jacket and (more importantly) the drier and colder the outside is the better the membrane will work. But those are hardly the conditions that require a WB Jacket.

Jacket breathability: Manufacturers now take the membrane and produce a jacket out of it realising that the membrane’s breathability alone is not enough to keep you dry. Hence the need for pit zips and other gadgets to be able to vent. This venting is good in part to dump moisture but also heat. Add onto this that you will more than likely be carrying a pack. This will cover half of the jacket’s breathing surface area (your back). Also if you put a big plastic covered map in your chest pocket then this will reduce the breathable surface area further.

So if all these jackets do not actually work well while running in the rain then why carry them? For if you are unable to continue with your run in bad weather. For example when you are walking out slowly or worse have to sit out a rain storm.

Getting wet is not actually a problem. It is getting wet added to cold or wind then you get very rapid cooling and trouble.

So what features do I look for when choosing a Waterproof Breathable Jacket for my next run?

First of all I don’t intend to run in the garment. It will spend 90% of its life in my pack so it needs to be light enough so that I don’t get tempted to leave it behind. It needs to work well enough to get me out of the poo when it hits. This is an emergency layer only. (unless you were at Skyrun last year. And then you were not doing much running in the rain) But I would always still take a windproof layer with as a running layer.

If I was ever that cold and desperate to need a waterproof jacket then I would also want the waterproof pants to go with it.

Breathability figures as indicated in advertising on comparative tests is an issue but not one of the core issues for me living in the Cape. If I was going to need it more often, living in the UK then I would take this into more consideration.

Hope this gets you thinking about how this emergency layer will work best.

Please let me know your thoughts below.

PUFfer Preparation 301

I have had an interesting email conversation with a fellow trail runner on gear and how to best use it stretching over the last few weeks. This conversation and my presentation at SSISA prompted me to put expand on ideas here. My comments are aimed specifically at PUFfer runners but are universally applicable. Let me know your thoughts.

Basic Action Suit:

The extreme alpinist Mark Twight coined the term Action Suit for alpinism. It is equally applicable here with some adaptations. I encourage you to observe other sports closely and see what you can learn. (on Giro a few weeks ago the boys all got to the top of a snowy Col only to be handed a newspaper and surgical gloves….)

DSC00371I prefer to be on the cold side of things. Heat is your enemy. (the more you sweat into your clothing, the more you will get cold when you stop) This is something that you can train. A few years ago I went to climb Mt Rainier with a colleague. We walked up the lower snow slopes to get to the camp. I wore a base layer and a wind breaker and a Buff® on my head. I was super vigilant to keep cool. My colleague however wore a base layer and an insulated waterproof breathable jacket. He was sweating buckets and when we stopped to eat some snacks he was instantly cold. I just layered over the top of my kit and was comfortable.

PUFfer runners on the bus www.jacquesmarais.co.za

PUFfer runners on the bus http://www.jacquesmarais.co.za

When you get off the bus in Cape Point you want to be cold and even shivering. Anything more and you will overheat within a few minutes of running exertion.

For  legwear it is either shorts or tights – really your call. Tights can help with chafing and will dry quicker as they are closer to your skin. Shorts tend to have more pockets to put stuff and rubbish.

Stevie doing in race kit

Stevie doing in race kit

On my body I wear a light polyester t shirt. A short zip really helps to regulate heat.

I do most of my temperature regulation by wearing a Buff® at the start in a beanie. I will remove this and replace with a cap. A running cap is awesome in that it keeps the sun (and rain) out of your face. I need all the head coverage and it works well to scoop water from a stream later to cool you down. M like’s her running visors but then she has loads of hair.



Comfort layers: Warmth, Water, Wind


Staying warm is relies on many things. One of them is insulation from the elements. That is actually quite simple. You need to trap air next to your body. This trapped air acts as insulation and is heated by your body. The more effectively that air is trapped the better that garment will work.

This comes down to two factors: Fit and fabric.

You want a snug fit so that you can effectively trap air next to your skin.

The fabric of the garment also plays a huge role here. You have three choices. I am not going to go into each in detail. You can read all the marketing gumf on each manufacturers web site. The basics are:

Polyester great at moving moisture.

Polypro (great cold weather base layer),

Wool (great natural fibre) Merino Wool has the ability to hold a bit more moisture so that it does not feel damp so it feels drier. It also does not feel like a plastic bag next to your skin and does not stink! We distribute Icebreaker in South Africa so I am a fan.

Some races have a fleece layer as part of the required kit list. Personally I prefer carrying two base layers. The outer with a short zip to regulate warmth. These are more effective at trapping heat and as a result will keep me warmer. The First Ascent Derma Tec is super warm. In fact I can only wear it when I am stationary (evenings when camping) I have never exercised in it but I am pretty confident that it will stand up to anything you throw at it in SA.

We have seen a few triathletes migrate up to the trail scene and with them compression gear in the form of spandex and lycra. These items work fantastically well but are no good in offering warmth. Spandex just does not have the same insulation properties as polyester, polypro or wool. You have been warned!

Waterproof breathable:

Last week I was in a new running shop and I was told that customers want cheaper waterproofs. I was shown a jacket with no hood, not seam sealed and about a quarter of the price of anything else. You get what you pay for!

Personally my waterproof BREATHABLE jacket forms part of my emergency kit. I have never run in one. But when the chips are down and you are moving slow or not moving at all you want one and you want it now!

OK so what constitutes a waterproof BREATHABLE?

A decent jacket should be waterproof (obviously) but also allow moisture to pass through the membrane from the inside out. A plastic bag is fantastically waterproof but does not breathe! You can look at the claimed numbers by manufacturers all over the net. If a jacket breathes well enough it should not need pit vents.

One thing you want to be carefull of is when you put the jacket on you are pretty committed. If you later overheat (or produce too much moisture on the inside of your jacket) and you take it off then you will cool down massively. So when you are putting your waterproof breathable on you are making a big commitment.


One of my best garments is my windproof. Each company makes one and they all work on the same principle.

I prefer something super light made from Pertex or similar. The fit is not as crucial as on a bike where you want a super snug fit.

Remember to treat it with Nikwax or similar in order to keep its DWR. In fact this layer will keep you comfortable in most conditions. This is due to the high breathability and the windproof fabric.

Emergency Gear:

I keep my emergency kit separate to my running gear. It contains:

Waterproof breathable jacket and base layer as a minimum;

Myprodol (I am in no way advocating using pain killers during a race. But when you have an accident you have two choices: either wait for a rescue, which will take hours or you can get yourself out of the worst of it),

latex gloves (I don’t plan to operate on anybody but to protect my fingers from the cold wind),

blister plasters,

space blanket (anybody who has finished Ironman and si wrapped in a space blanket will know how well it works),

whistle (Is more audible and distinctive than a shout and takes less effort to make a sound)

Nutrition and Hydration:

I like to keep Nutrition and Hydration as separate as possible.

What happens when you are low on nutrition but feeling bloated from drinking too much?

What happens when you want liquid but not nutrition?

Separating the two gives you more options.

Currently I am using 32Gi products as they suit my objectives and general nutrition right now. See my previous post here. Variety works for me. I don’t use gels early on as it blocks my stomach later. I would like to experiment with a concentrated mix of 32Gi going forward to see how that works. I regularly read what Allen Lim has to say. I find that eating solids definitely helps in keeping my stomach happy. It does clog up my throat a bit for hard running efforts though.

I put pure water into my hydration bladder or bottles.

I have both planned out before hand and my second knows exactly what to give me when. I have two bum bags that I swap at every check point and they have right hydration and nutrition pre packed.

In order to carry the above hydration and nutrition you have a couple of options:

Me wearing a bum bag only while other runners have their torso covered with back packs

Me wearing a bum bag only while other runners have their torso covered with back packs

Racing vests are very popular at the moment. They carry a lot of kit and are least restrictive on your running style but I do feel that they are pretty hot and prevent shedding heat.

If I can then I use a bum bag. This does put more weight on your hips and thus influences your centre of gravity more noticeably. But the advantage of staying cooler is huge. It is also super easy to refill bottles compared to a hydration bladder. Downside you can’t carry as much kit.

Please understand I am not claiming any of this to be the right or only way. It is working for me, right now. Let me know your thoughts.

Now go and enjoy the race!