Waterproof Fabrics Buying Guide
The market for waterproofs is diverse and complex. Competition revolves around breathability - the ability of a fabric to evacuate sweat/vapour and maintain a comfortable microclimate inside the garment during activities.
GORE produces some of the most well-known waterproof materials. Their range includes GORE-TEX Pro, which is designed to give waterproof and breathable protection in the harshest conditions, and GORE-TEX Active, which provides highly breathable and waterproof performance perfect for those moving fast and light.
Good alternatives to GORE-TEX are also available, from other ePTFE (expanded Polytetrafluoroethylene) membrane options like eVent to the less expensive PU film fabrics like The North Face’s DryVent, Patagonia’s H2No and Pertex Shield.
All the types listed here are both waterproof and breathable to varying degrees, but choosing waterproof clothing also depends on many other factors; the brand, the fit, the pockets, the hood, the colour! Knowing the main features and benefits of each different fabric is just the first step in choosing the right garment for your intended activity.
How Do Waterproof Fabrics Work?
Creating a fabric that blocks rain is easy. Creating a fabric that blocks rain yet still allows your sweat to escape is much more difficult. However, all waterproof fabrics work on the same principle: diffusion. Molecules will move from areas of high concentration to areas of low concentration. Hence when you warm up and create moisture, it wants to pass through your waterproof jacket to reach the lower concentrations outside. Different waterproof materials achieve this in different ways.
ePTFE Membranes with a PU coating (eg. GORE-TEX)
Traditional GORE-TEX (introduced in 1978) paved the way by using a stretched PTFE membrane containing 9 billion microscopic pores per square inch. These pores are 20,000 times smaller than a water droplet (so rain can't penetrate) but also 700 times bigger than a molecule of moisture vapour (so vapour can escape). This 'sieve' of microscopic holes is backed by an ultra-thin oleophobic polyurethane coating which prevents body oils from contaminating the membrane. The PU coating also completely blocks the wind, which is what gives a GORE-TEX garment its windproof properties.
As you sweat, vapour condenses on the lining and passes through the polyurethane coating as a liquid, reaching the ePTFE membrane where it evaporates out through the network of microscopic holes. It is the differential between the warm, moist internal climate and the cooler, dryer external climate that drives vapour through the fabric's pores away from your skin. So the harder you work, the warmer you get and the faster the whole process works.
ePTFE Membranes without a PU coating (eg. eVent / NeoShell)
These fabrics all utilise an ePTFE membrane without a protective PU film (or in some cases with a PU film that encircles the pores, leaving them uncovered). Since there's no cover over the pores, the membrane is able to breathe more effectively. Fabrics like this can take air in as well as pushing moisture out. It's a two-way air flow that disperses moisture by convection (air circulation) as well as diffusion (pressure gradients).
A downside of this system is that without a PU film the membrane may be more prone to contamination. It is possible to build an oleophobic treatment into the membrane but this may be less effective or durable than the traditional GORE-TEX method. Pores left open will breathe better but may become clogged with oils and dirt more easily, meaning you may need to wash the garment more regularly. Wearers may also experience more rapid cooling in high windchill situations though garments will still be roughly 95% windproof.
Waterproof membranes or PU films are sandwiched between an outer layer (or 'face fabric') and an inner layer ('scrim') sitting next to the skin. The face fabric adds durability and carries the DWR. The scrim wicks moisture outwards and helps protect the film and membrane from contaminants. The nature of the inner layer determines whether a fabric is 3, 2.5 or 2 layer.
- 3 Layer (eg. GTX Pro) - outer, membrane and inner are bonded together into one flexible material
- 2.5 Layer (eg. GTX Paclite) - outer and membrane are bonded together and given a very thin internal carbon or texturised 'half layer'
- 2 Layer (eg. GTX) - outer and membrane are bonded together, but the internal lining is a loose-hanging fabric or mesh
The Importance of Durable Water Repellency (DWR)
When water hits a brand new waterproof jacket, it will 'bead up' and run off. This is because the surface has a Durable Water Repellent (DWR) coating. A poorly-maintained jacket will often 'wet out', with water soaking into the face fabric. When this happens, the flow of moisture from within is disrupted. Vapour can't escape because it is blocked by the water droplets drenching the face fabric. Wearers may feel wet. This sensation is caused by trapped sweat building up inside the wetting-out jacket, not by any leak. The solution is to re-apply the DWR using Grangers or Nikwax.
You can make a jacket from waterproof material, but unless you seal the seams it will leak very quickly. Look inside a waterproof jacket and you will see strips of tape covering the seams. This taping will not let moisture through in either direction so the more taping, the less breathable the jacket. It also stiffens the seam area. That's why Arc'teryx and others strive to reduce the number of seams and the width of the tape used. Tape is usually essential, but reducing the amount results in a lighter, more supple and more breathable jacket.
There are a variety of tests and measures used to quantify performance but none are standardised or accepted industry-wide. The important thing is to take any quoted figures you see with a pinch of salt and bear in mind that a variety of factors – for instance the type of face fabric or the taping pattern used - can affect the performance of individual styles.
GORE-TEX Fabric Guide
GORE-TEX Pro is the top end waterproof/breathable fabric designed for sustained use by mountaineers and those out in bad conditions on a regular basis. This fabric features multiple layers of expanded PTFE bonded to the outer material and a gridded backing textile, but it doesn’t have an oleophobic PU layer. The innovative construction means it offers excellent breathability, but the emphasis is still on durability for extended use. Outer fabrics must be a minimum 40 denier so GORE-TEX Pro garments are rugged and reliable. We stock GORE-TEX Pro jackets from an impeccable range of brands including Arc’teryx, Mountain Equipment, The North Face, Black Diamond and Mammut.
GORE-TEX Active is their fabric for fast and light consumers. Lamination technology integrates the backer textile directly into the waterproof membrane for a streamlined, very breathable package. Working well in lightweight alpine garments, GORE maintains a focus on minimalist designs by stipulating that pockets must not cover more than an A4-paper sized area.
This is effectively 'Performance Shell' fabric, the tried-and-tested GORE-TEX membrane. It is available in either a 2-layer construction or as a 3-layer laminate, the former featuring a hanging 'drop' liner reminiscent of traditional hill walking gear. Both versions offer the usual waterproof/breathable performance, making them well suited for cooler autumn or winter weather.
- 2 layer with drop liner or 3 layer laminate
- Classic membrane available in different formats for different end users
- Rugged construction allows a long life-span and year-round use
- Supple fabrics enhance comfort for a range of outdoor activities
- Styles appeal to traditional hill walkers who value practicality
The fabric that does what it says on the tin; it packs down small and light. A carbon 'half layer' backer protects the membrane from contamination meaning a full-scale lining is unnecessary. This results in a smaller pack size than most other waterproof garments. It's an excellent choice for occasional use such as trekking or travel where it may sit in a pack until rain starts falling.
Gore’s C-Knit backer technology combines the ruggedness of a 3-layer laminate with the look and feel of a soft interior fabric. The result is a waterproof material that gives outstanding comfort without compromising function or durability. With GORE C-KNIT, garments are lighter, softer and even more breathable than comparable previous products, and slide easily over other layers for ultimate wearability. Ideal for outdoor enthusiasts, waterproof garments with GORE C-KNIT can be used for hiking, skiing, snowboarding and more.
GORE-TEX with SHAKEDRY product technology is a revolutionary waterproof material that has no external face fabric. Instead the laminate acts as the weather barrier, providing full waterproof, windproof protection. By removing the face fabric breathability is significantly increased while weight and pack size is reduced. On the inside is an ultralight textile backer, for enhanced next-to-skin comfort. Items using GORE-TEX with SHAKEDRY product technology have been designed with high output activities in mind, making exceptional choices for trail running and fast and light hiking.
Alternative Waterproof Fabrics
The North Face DryVent
The North Face's own brand fabric uses a polyurethane (PU) coating. This is applied in a thin, even layer across the back of the face fabric. Your sweat is transported across the hydrophilic PU by diffusion, moving from the warm, moist atmosphere next to your skin to the cooler, dryer atmosphere outside. The front of the face fabric is treated with a Durable Water Repellent (DWR) finish; this helps water droplets to form and repels them from the surface. All DryVent clothing and accessories are fully seam sealed for increased protection and durability.
The North Face produces DryVent in 2 layer and 2.5 layer constructions, allowing them to maximise protection, performance and comfort across a wide range of outdoor products.
- 2.5 layer with 'dry touch' textured print inside
- Dry touch print raises fabric from the skin for enhanced comfort and faster vapour transfer
- Offers lightness and performance in the lower price spectrum
- Used in sporty styles for active outdoors people, yet still great for everyday use
- 2 layer with drop lining
- Drop lining is comfortable next-to-skin and increases warmth
- Good balance of waterproofness and breathability
- Excellent value for the cost-conscious customer
- A great year-round ('Triclimate') option when layered over a fleece
H2No is Patagonia's own-brand waterproof fabric. All H2No fabrics undergo the 'Killer Wash', a proprietary wet flex test which simulates a lifetime of use and abuse. Their Performance Standard dictates that fabrics must have a hydrostatic head of 20,000mm before and 10,000mm after the Killer Wash (though many specific H2No fabrics will exceed these figures). The standard applies from their top-end mountaineering shells down to their classic rain jackets made with everyday use in mind.
Pertex Shield fabrics use a PU film coating to provide lightweight waterproof protection while remaining highly breathable. A DWR treatment on the face fabric sheds rain and snow, which also helps to maintain breathability. Available in 2, 2.5 and 3-layer constructions for versatility, the soft and stretchy outer fabrics ensure a supple and comfortable feel, while low weights and small pack sizes make Pertex Shield garments well suited to active outdoor pursuits.
eVent is a patented ePTFE membrane that works in a similar way to GORE-TEX, with millions of microscopic pores which keep rain out but allow vapour to escape. It claims greater breathability than traditional GORE-TEX and over the years many users have agreed. The downside is that the ePTFE pores are not well protected from contamination so eVent may need more regular washing to maintain performance.