Singletrack World Issue 145: The Science Of Waterproofing

Fresh from a wet weather ride where he appeared to be wetter on the inside than the outside, Sanny sets off to find out what ‘waterproof clothing’ act …

By sanny

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Singletrack World Issue 145: The Science Of Waterproofing

The first elephant in the room here is that regardless of what fabric you use and how well cut and designed the jacket is, it will still have a bloody great upwards-facing hole which your head goes through and in anything resembling heavy rain, water will run down it. Particularly if you don’t have a hood, but even then to an extent.

The other elephant is the D in DWR, as pretty much all durable water repellent treatments turn out to be not very durable at all and once they stop working – usually a matter of hours or less – the outer face of the fabric soaks up water and drastically reduces moisture vapour transfer (aka breathability) from the inside of the garment outwards and you soak in your own sweat.

The two exceptions I’m aware of are Columbia’s OutDry Extreme and Gore’s ShakeDry, which do away with face fabrics altogether and have the proofing later on the outside, hence the gimpy, rubbery appearance of both fabrics. They don’t use a DWR and consequently they don’t wet out.

Oddly enough, manufacturers don’t really want to talk about either, fwiw, wearing a buff around your nexk reduces the problem with the hole for your head, but the relative uselessness of DWR treatments renders a lot of the breathable technology spiel semi-irrelevant ime.

Not sure it was addressed directly but one question is: waterproof for how long?

Maybe it’s strongly related to the ‘D’WR treatment as @badlywireddog describes. As was said ‘the perfect waterproof coat doesn’t exist’. I suppose that means multiple jackets with all the choice and cost problems that introduces but with small compromises or a general compromise. I favour the latter. In most cases in England and Wales being a bit wet and cold is only going to be uncomfortable for a short time – it won’t hurt you.

‘Regular washing’ right, every gore-tex coat we’ve had in this house has survived a handful of washes before taping and seams started falling apart. Unless they’re deeply grimy or completely wetting out our jackets now get a scrub under the shower and a spin in the drier.

The holes – oh yes! And the temperature difference. At night in a steamy, heavy Florida storm our coats lasted about 5 minutes before we were sodden. …should’ve taken an umbrella.

… it will still have a bloody great upwards-facing hole which your head goes through and in anything resembling heavy rain, water will run down it.

If you plan on swimming in it maybe. I’ve been out in all kinds of weather over the years, in various jackets, and I can’t say the hole in the top has been the problem with any of them.

This happens with shoes, but only where there’s lots of standing water and the wheels direct a constant jet of water just above that hole. Generally, even a heavy deluge of rain coming from above isn’t enough to penetrate those parts significantly in my experience.

If you plan on swimming in it maybe. I’ve been out in all kinds of weather over the years, in various jackets, and I can’t say the hole in the top has been the problem with any of them.

In my experience, there’s a point where rain is heavy enough to simply run down your neck. Some of the time, from drizzle through to moderate showers, it’s not an issue, but in heavy rain, I’ve found that it is.