{"id":69769,"date":"2024-10-02T18:00:00","date_gmt":"2024-10-02T16:00:00","guid":{"rendered":"http:\/\/10e1f017-a0cc-494c-b648-495aab32a426"},"modified":"2024-10-02T19:25:28","modified_gmt":"2024-10-02T17:25:28","slug":"why-breathable-waterproof-clothing-is-a-myth-according-to-three-experts","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/cyclingplus\/rss_feed\/why-breathable-waterproof-clothing-is-a-myth-according-to-three-experts\/","title":{"rendered":"Why \u2018breathable waterproof\u2019 clothing is a myth, according to three experts"},"content":{"rendered":"

Your expensive jacket can be one or the other, but not both at the same time <\/p>

By Simon von Bromley\n <\/p>

Published: Wednesday, 02 October 2024 at 16:00 PM<\/p>

\n\n

Waterproof fabrics have seen plenty of development in recent decades, but are their capabilities being overplayed?<\/p>

Almost every brand promises their waterproof jackets<\/a> can lock out water on rainy days yet still allow sweat to \u2018breathe\u2019 through, to prevent you getting soaked from the inside.<\/p>

Is this possible, though?<\/p>

And if your current waterproof jacket isn’t all it’s cracked up to be, is there anything you can do to stay dry and comfortable when cycling in wet weather<\/a>?<\/p>

To answer these questions, we spoke to three experts on waterproof fabrics; Charles Ross, lecturer and specialist in performance sportswear design at the Royal College of Arts, Thomas Plummer, head of apparel at Madison, and Tim Wilson, managing director of Storm Care.<\/p>

How modern waterproof fabrics were invented<\/h2>
Gore invented the ePTFE waterproof membrane. <\/figcaption><\/figure>
Before we get to why common waterproof fabrics may not work exactly as advertised, let\u2019s take a look at how modern breathable waterproof materials were invented and how they function.<\/p>
In 1958, Bob Gore (of Gore-Tex<\/a> fame) created expanded polytetrafluoroethylene (ePTFE).<\/p>
Gore\u2019s father, Bill Gore, had worked at DuPont, the American chemical company, where standard PTFE \u2013 or Teflon as it was later branded \u2013 had been invented 20 years earlier.<\/p>
Working with his father, Bob discovered that if you vigorously stretch PTFE it expands rapidly and forms a microporous structure.<\/p>
$\"Microscopic$
Viewing ePTFE under a microscope shows how porous it is. Gore<\/span><\/figcaption><\/figure>
According to Charlie Ross, a typical ePFTE membrane contains around \u201ca million holes per square inch\u201d.<\/p>
The tiny size of these holes means ePTFE is permeable to microscopic particles of water vapour, but impermeable to larger water droplets \u2013 hence the claim it\u2019s \u2018breathable\u2019 and waterproof.<\/p>
To create a fabric from which garments can be constructed, an ePTFE membrane is sandwiched between two layers of nylon or polyester fabric, to help protect the membrane from abrasion and dirt.<\/p>
This forms what\u2019s commonly referred to as a \u2018triple-layer\u2019 (sometimes called a \u20183L\u2019) waterproof fabric.<\/p>
$\"Water$
The outer layer of a three-layer waterproof fabric is typically treated with a DWR coating. Simon von Bromley \/ Our Media<\/span><\/figcaption><\/figure>
On these fabrics, the outermost layer is typically coated with a Durable Water Repellent (DWR) coating, designed to prevent the fabric saturating with water \u2013 or \u2018wetting out\u2019 as it\u2019s commonly called.<\/p>
A fabric \u2018wetting out\u2019 is a problem because having a layer of water on the outside of the fabric blocks the transfer of water vapour from the interior of a garment to the exterior, as the humidity on the outside of the fabric effectively becomes 100 per cent.<\/p>
So far, so good, then, but this belt-and-braces approach isn\u2019t without its drawbacks.<\/p>
Primarily, DWR coatings wear out and need to be refreshed over time \u2013 and, if neglected, waterproof fabrics tend to \u2018wet out\u2019 much quicker. This is why specialist detergents and cleaners from brands such as Storm Care and Nikwax exist.<\/p>
$\"How$
Gore introduced its Shakedry fabric in 2015, but it’s now being discontinued. Felix Smith \/ Immediate Media<\/span><\/figcaption><\/figure>
In late 2015, though, Gore unveiled Shakedry<\/a>, a two-layer fabric with the ePTFE membrane on the outside.<\/p>
Eschewing the outermost layer made for a lighter fabric, but it also negated the need for a DWR coating \u2013 because the hydrophobic nature of the ePTFE membrane didn\u2019t require one \u2013 solving the issue of such coatings degrading over time.<\/p>
Why Gore-Tex isn\u2019t magic<\/h2>
$\"Pa\u0301ramo$
When it’s raining, the concentration of water vapour in the air around you naturally increases. Reuben Bakker-Dyos \/ Our Media<\/span><\/figcaption><\/figure>
According to the brand and many testers (including here at BikeRadar<\/a>), Shakedry set new standards for breathable waterproof materials.<\/p>
However, it\u2019s vital to appreciate how such materials \u2018breathe\u2019 in order to understand how they work, and, perhaps more importantly, how they don\u2019t.<\/p>
It is true that an ePFTE membrane can simultaneously be impermeable to water and permeable to water vapour. However, the conditions under which water vapour will diffuse from one side to the other are specific and, typically, don\u2019t occur when you need them most.<\/p>
As with any gaseous diffusion, waterproof membranes rely on a partial pressure gradient to transfer water vapour from one side of the fabric to the other.<\/p>
For your sweat to \u2018breathe\u2019 through the fabric of a waterproof jacket, for example, the air outside the fabric must be less humid (meaning it has a lower concentration of water vapour) than on the inside.<\/p>
When it\u2019s raining, though, Ross says \u201cthe outside humidity can be 85-90 per cent\u201d, meaning the air is almost completely saturated with water vapour.<\/p>
As a result, there isn\u2019t a partial pressure gradient between the inside and outside of the fabric, and water vapour can\u2019t \u2018breathe\u2019 out from within until the humidity inside builds to the point that one is created (by which point you will, by definition, be very sweaty).<\/p>
$\"Interior$
Waterproof fabrics can breathe, but only under the right conditions. Simon von Bromley \/ Our Media<\/span><\/figcaption><\/figure>
In reality, then, \u2018breathable waterproof\u2019 fabrics are both \u2018breathable\u2019 and \u2018waterproof\u2019, but not at the same time.<\/p>
They can \u2018breathe\u2019 when it\u2019s dry and keep water out when it\u2019s wet \u2013 but if you\u2019re working hard enough to induce sweating when it\u2019s humid outside, you\u2019ll still get wet on the inside, no matter how expensive your waterproof jacket is.<\/p>
Even on dry days, though \u2013 when ePFTE membranes breathe best \u2013 Ross says you\u2019ll likely be better off with a windproof jacket<\/a> than a waterproof one.<\/p>
This is because windproof jackets are typically made solely from woven fabrics (with correspondingly larger holes between the fibres) and don\u2019t feature a waterproof membrane.<\/p>
How incoming PFC bans will affect waterproof clothing<\/h2>
$\"Close$
DWR treatments have traditionally been made from PFCs, but these are being phased out. Simon von Bromley \/ Our Media<\/span><\/figcaption><\/figure>
Making matters more complicated, both the European Union and United States have recently placed restrictions on the manufacturing and use of perfluorinated compounds (PFCs) \u2013 the stuff that PTFE, ePTFE and DWR coatings are also typically made from.<\/p>
These chemicals (often referred to as \u2018forever chemicals\u2019 because they don\u2019t degrade in the natural environment) can be highly toxic under certain circumstances, with links to cancer and a range of other ailments.<\/p>
As a result, most manufacturers of waterproof garments are phasing out the use of PFCs where possible.<\/p>
Gore, for example, says it \u201chas set the goal of eliminating PFCs of Environmental Concern from the life cycle of its consumer fabrics products\u201d.<\/p>
According to Gore, \u201cPFCs of Environmental Concern\u201d are \u201chighly fluorinated, small enough to be bioavailable, and persistent.\u201d It says this definition was agreed in accordance with Greenpeace.<\/p>
Notably, Gore doesn\u2019t include its ePTFE membranes in this category, though. It argues ePTFE is chemically inert and therefore isn\u2019t toxic (something Ross echoes). Given this, it will continue to produce its traditional ePTFE membranes for use in waterproof gear.<\/p>
Many influential brands are moving towards PFC-free solutions as they seek to produce more environmentally friendly products.<\/p>
With that in mind, Gore developed a three-layer waterproof fabric with a ‘PFC-free’ expanded polyethylene (ePE) membrane and a PFC-free DWR treatment in 2021, which is used by brands such as Adidas and Patagonia.<\/p>
$\"GORE-TEX$
Gore’s new ePE membrane is claimed to be ‘PFC-free’. Gore<\/span><\/figcaption><\/figure>
Pertex\u2019s Shield waterproof fabric, meanwhile, is made with an expanded polyurethane (ePU) membrane. This fabric is used by brands such as Albion and Altura.<\/p>
According to Pertex, the breathability of its ePU membrane \u201cis dynamic\u201d and \u201crises as the output of the user increases\u201d (as long as the outside air is dry enough to allow water vapour to diffuse from inside to outside of the jacket, we presume).<\/p>
Wilson says that, initially at least, riders are likely to see a reduction in performance from such \u2018PFC-free\u2019 garments compared to existing ones, particularly with regards to how long the factory-applied DWR treatment will last.<\/p>
As a result, owners of such gear should expect to maintain or rejuvenate the DWR treatment on a PFC-free jacket more frequently (check out our guide to reproofing your waterproof cycling gear<\/a> if you need a refresher on this).<\/p>
$\"Storm$
Brands such as Storm Care make a range of products to keep waterproof gear performing optimally. Storm Care<\/span><\/figcaption><\/figure>
He also says PFC-free waterproof fabrics could be less durable and resistant to contaminants such as dirt and oil.<\/p>
This in particular, Plummer says, is a cause for concern because riders may feel the need to replace their gear more often if it wears out or simply looks tattier more quickly \u2013 something that wouldn\u2019t be good for the environment either.<\/p>
However, he also says performance of PFC-free waterproof fabrics should improve over time, as brands develop new technologies and products.<\/p>