A Guide To Buying A Waterproof Jacket

When looking to buy a waterproof jacket, first consider what you need it for. Here are steps to help you decide the best waterproof jacket for your activities. 


STEP 1

What makes something waterproof?

The word 'waterproof' is a slightly subjective term for the outdoor clothing world. We want a garment that will stop water - such as rain or snow and keep us thoroughly dry, however for that to work it will also stop any moisture from leaving the inside. We all sweat especially if we are working hard (walking up a hill maybe) and if that sweat cannot escape then we may end up feeling just as wet as if we had no waterproof garment on at all. The solution is a jacket that stops water from getting in but also lets moisture out.

‘Waterproof’ is stopping water getting in and ‘breathability’ is letting moisture out. The third thing we want from a waterproof is 'durability'. Something that will survive the wear and tear of the activities we use it for.

As you can probably guess it is impossible to get an item of clothing (or even something like a tent) that will do all three of these perfectly. So there has to be a trade-off between the three. Outdoor waterproof brands try to make jackets or over-trousers that are bespoke to the activity requirements. For example, if it is for running, a jacket will be highly breathable and light. A running jacket will not be as waterproof or durable as one required for trekking in harsh Alpine conditions, but this jacket conversely will not be as breathable.

How To Measure Fabric Waterproof-Ability

A tall tube is placed over a waterproof fabric which is slowly filled with water until the pressure of the water causes the fabric to leak. The height of the water is measured, this is known as the hydrostatic head (H/H) and is the measurement of the fabrics waterproof ability. The minimum British standard which qualifies a fabric as waterproof is 1,500mm of water. That is if a fabric can withstand the pressure of a height of 1,500mm of water in laboratory conditions and not leak it is deemed ‘waterproof’.

The basic guide to waterproof ratings for garments are:

  • A fabric with a H/H of between 500mm and 1,500mm is suitable for light rain.
  • A rating up to 10,000mm will keep you dry in moderate to heavy rain.
  • Between 10,000 and 20,000 a garment is rated as highly waterproof in the heaviest rain showers.

Even so, this is a somewhat subjective value because it does not take into account such factors as wind pressure and the dynamic pressure caused by falling rain. It does give us a comparison between different waterproof fabrics, although unfortunately (perhaps wisely!) most brands do not give the ratings of their waterproofs.

How To Measure Fabric Breath-ability

Breathability or Moisture Vapor Transmission Rate (MTVR) is also measured in laboratory conditions. Over a 24 hour period, the rate that water vapor passes through a square meter of fabric is measured in grams, this is often simply expressed as ‘g’.

When looking at breathabilty you should also consider the climate. The breathability of a garment very much depends upon the relative climates of the microclimate inside the jacket and the weather climate outside the jacket. If the weather is hot and humid the breathability of a garment will not work as well as it would if the weather was cold and dry. 

It may not be clear what the jacket breathability rating is, but most outdoor brands will give information on what the fabric is developed for. Recent development has seen The North Face produce FUTURELIGHT, a membrane, and fabric made to rival GORE-TEX which is the leading waterproof-breathable material. The fabric is focused on improving breathability and comes in multiple thicknesses and types. The membrane is a nano-spun polyurethane.

 

Examples of breathable and waterproof jackets


STEP 2

Waterproofing methods used in construction

It may surprise you to find out that the outer fabric of a jacket is not what keeps you dry. The outer fabric is usually a woven polymer, the function of which is to protect you and the waterproofing. Damage can be caused by rubbing against such things as rocks and undergrowth. Some companies use recycled polymers in order to reduce plastic waste. The jackets durability is usually achieved by a greater thickness of fabric which is measured in units called Denier normally donated as ‘d’.

First, let's talk about DWR (durable water repellent) this is a coating added to the outside of the fabric in the factory. It is not in itself waterproof but is the first barrier against outside moisture, it is water ‘resistant’. It will make water hitting the fabric initially bead and roll off of the garment, this stops the garment from getting soaked known as ‘wetting out’ which hinders the waterproof fabrics functional ability. Unfortunately, the same water will eventually wash the DWR off and a jacket or trousers will need reproofing, which in itself is simple enough.

One of the problems with DWR coatings is that they require the use of Perfluorocarbons (PFC,s) which are considered harmful to the environment. Many outdoor clothing manufacturers are committed to finding an alternative DWR and have already transferred from using long-chain fluorocarbon finishes (C8) to the shorter chain (C6) which is considered less harmful.

Denier is used to determine the thickness of the fiber in the fabric.

It’s a unit of density based on the length and weight of yarn or fiber. A single strand of silk is considered 1 denier. The fibers in a 40-denier nylon fabric have over 6.5 times the diameter of the silk strand and almost 1.5 times the diameter of fibers in a 20-denier or “20D” nylon fabric. As you can see, the higher the denier count, the greater the diameter of the yarn. A larger denier number often means it is stronger, but not always. Strength also depends upon the material.

 

EXAMPLES OF DURABLE WATERPROOF JACKETS WITH A THICK DENIER

Fabrics are made waterproof by one of two methods which are both applied to the inside of the outer fabric.

Coating

This is generally the simplest way of waterproofing a jacket. A liquid coating is applied to the inside of the jacket fabric, much like applying paint to a wall with a roller. The more layers that are applied the more durable the waterproofing but the less breathable. This is a less dynamic method that basically means the garment will be stiffer.

Membrane or Laminate

This is the most common method of waterproofing a garment. A fine film is bonded to the back of the fabric which is thinner than a human hair. The finer the membrane the more breathable the jacket. You may recognise the name GORE-TEX, who offer the best and biggest range of waterproof, breathable fabric membranes.

GORE-TEX

Probably the best known waterproof membrane, you will see GORE-TEX labels on jackets, trousers, and boots. GORE-TEX is stretched Polytetraflouroethylene (PTFE) known to most of us as ‘Teflon’. The stretched PTFE has loads of microscopic pores in its structure, in fact, there are nine million of these pores per square inch. These pores are 20,000 times smaller than a drop of water and 700 times larger than a moisture vapor molecule. 

This means that the unique properties of GORE-TEX stop water from passing through while also allowing moisture vapor to pass through. This makes it ideal for outdoor clothing because it will keep you dry from the rain, while allowing your body to breath as the gas, heat, and moisture produced from your body freely flows out and away, helping you to maintain comfortable body temperature and not get ‘wet’ from your own sweat.

Every product in the original GORE-TEX product range, with the GUARANTEED TO KEEP YOU DRY™ promise, is made for best-in-class, durable waterproof and windproof protection, plus breathability. The new GORE-TEX INFINIUM™ product range is designed for flexibility, functionality, and style to support your active life—when comfort and performance take priority over waterproof protection. From weekday commuting to weekend getaways, this new range offers you versatile comfort.

 

eVent

There is one other common form of waterproofing that we must mention - that is eVent. eVent is a patented ePTFE with properties similar to GORE-TEX, it is highly breathable, waterproof membrane constructed of millions of micropores, the pores ‘vent’ out sweat - called ‘direct venting’.

GORE-TEX has an oil-repelling PU layer which makes it thicker than eVent that is a one layer membrane. This means that eVent is generally more breathable than GORE-TEX, however, because it does not have the protective PU layer the pores become clogged more easily, this means for an eVent jacket to work well it requires washing and reproofing more frequently. eVent is ideal for fast-paced activities where the wearer may sweat a lot and get hot, conversely, an eVent jacket can feel slightly colder than a GORE-TEX one when in exposed cold conditions. 

eVent Graphic

Other waterproofing brands

Since the patent for GORE-TEX ran out many outdoor brands have copied the technology with their own brand names. Outdoor brands have adopted their own brand name of waterproofing because to use GORE-TEX they need to apply for a licence from the company. These also tend to be cheaper than GORE-TEX products.

Examples of these are:

Pertex® Shield fabrics are durable, waterproof and highly breathable. They have been developed to provide lightweight and versatile protection from the elements. used by Rab and Montane.

Dryvent created by The North Face. DryVent™ fabrics are engineered to be fully waterproof, windproof and breathable. The outer face of the textile is treated with a durable water-repellant finish that helps form droplets and repel water from the surface. Each multi-layered textile is engineered to allow water vapor to pass through from the inside to the outside. Engineered in a variety, weights, textures and performance characteristics that allows us to provide maximum protection, performance and comfort for the user across all our active and lifestyle waterproof, breathable clothing and accessories. DryVent™ clothing and accessories are fully seam-sealed and designed with specific features that are relevant to the user’s specific activity needs and conditions. All products that are fully taped, waterproof and breathable will be branded DryVent™.

Exclusive to Jack Wolfskin: Texapore was developed in-house by Jack Wolfskin to provide best-in-class weather protection. 

AQ™ and Hydroshell are developed by Berghaus as their waterproof technologies, they are a tried and tested fabric which has been specially designed to keep you warm and comfortable thanks to advanced waterproof properties.

Drilite® is Mountain Equipment's exclusive waterproof, breathable and durable fabric.

Examples of jackets with own brand waterproof technologies

Waterproof Layers

There are three waterproofing layer structures recognised in the outdoor clothing industry.

2L

This is the simplest and lightest of if the layering systems.

It consists of outer fabric with a membrane or coating bonded to it.

To protect the membrane often a mesh inner layer is added to the jacket. This 2L waterproof system can also be lined with other fabrics for comfort or warmth which makes it very versatile and is incorporated into a wide variety of jackets for many activities. 

2.5L

The waterproof membrane is bonded to the outer fabric then a coating or print is applied to the inner face of the membrane to protect it from abrasion and wear and tear.

This enables the jacket to be light and highly packable and is often used for very active, light and fast pursuits.

3L

The waterproof membrane is sandwiched between the outer fabric and a woven or knitted inner fabric which makes it more durable but also heavier.

This layering is used in jackets for those who wish to engage in more extreme activities, the outer fabric is often a thicker denier for greater robustness in severe conditions.

The jacket will maintain it’s breathability for a longer duration but will not be as efficient as the lighter engineered fabrics.


STEP 3

Choose Your Features and Fit

There are two major factors governing choosing a waterproof jacket:

1. What do you need it for?
2. How much are you willing to invest?

To get the best value for your money serious thought should be given to what you actually want the jacket for. Jackets vary a lot in price and this is usually related to the activity the jacket is designed for.

If you are wanting a waterproof for walking the wilds of Scotland in the winter season then you will want a robust highly waterproof jacket with the best breathability possible, that will be fairly expensive. Perhaps you are a runner, then lightweight and maximum breathability will be the two major features you will be looking for, or if you simply want a waterproof for walking the dog then a less expensive, less breathable not so robust jacket that will keep you dry will fit the bill nicely. 

To get the best out of wearing your waterproof jacket in different temperatures it is best to adopt a layering system. Your waterproof jacket will be the hard outer shell that protects you from the elements. Different layers of clothing are worn under the waterproof to keep you warm according to the outdoor temperature, These garments need to be efficient ‘wicking’ in order to allow the waterproof to breathe efficiently. Hikers and people who prefer layers usually buy a jacket one size larger than they normally wear. This ensures sufficient space for the other layers like fleece, softshell and baselayers. Here are features to consider when looking at a waterproof jacket. 

The stitchingLook at the general construction of the jacket. A waterproof is constructed from various cuts of fabric that are stitched together. The holes created by the stitching are places where water can penetrate the jacket and make the wearer wet. To solve this problem manufacturers seal the seams with a seam sealing tape. The tape is heat-sealed to the inner fabric to provide good contact and flexibility. 

Zips. The zips on a garment is another point where water can penetrate especially the front zip of a jacket. Many brands use YKK AquaGuard zippers which are manufactured to prevent such water penetration. They also incorporate a storm flap behind the zip, and jackets designed for especially harsh conditions have another flap on the outside covering the zip.

If you don’t like to layer and want breathability, look for jackets with venting ‘pit zips’ under the arms.

Pockets. Most jackets have hand pockets, these are usually situated at a comfortable position at the front of the jacket and are zipped. The pockets are worth consideration when buying a jacket for several reasons. Firstly pockets are not usually very waterproof themselves, then if you are wearing a backpack or climbing harness you may not want the belt of your pack or harness to cross the pockets making access difficult, and finally the size of the pockets may be a factor if, for instance, you want to keep you map in them. Often a jacket will have a Napoleon pocket on the inside or outside. Pockets on trousers vary a lot, some do not have any.

Length and fit. It is important that the back of your waterproof jacket extends below your lower back. This is so your back is never exposed, even during sports where your arms are outstretched.

Think about whether you’re going to be wearing multiple layers under your jacket or just a base layer. If you want a regular fit jacket, look for a slimer fit.

Velcro, hook and loop. The most common way to adjust and seal the cuffs of a jacket is with a hook and loop system, on some jackets the cuffs are elasticated.

Pull cords The hem of a jacket or waistline of trousers is often sealed with a drawcord although sometimes these are elasticated. Similarly the hood of a jacket is usually adjusted with a drawcord.

The hood. Nearly all waterproof jackets have a hood, these are often helmet-compatible, that is - a climbing helmet can be worn either over or under the hood. This is great if you are a climber but for walkers, it can make the hood difficult to adjust so that it is practical and comfortable. Most hoods have a peak, these vary from simply being a ‘floppy’ piece of material to being stiffened or wired.

Weight. If you’re traveling light, or plan to stow your jacket rather than wear it, then looking at the lighter end of the range makes sense. If you’re expecting to wear your jacket for activities that might cause heavy abrasion or require resistance to tearing then it’s probably wise to look at the heavier end.

Pack Size. If you’re planning on wearing your jacket all day then the packed size might not be a concern, but if you’re traveling light, or need something you can throw on at a moment’s notice, then it can make a big difference. Some jackets pack down into their own pockets or, come with their own stuff sack.


STEP 4

Washing and Caring for Waterproof Jacket

A waterproof can last a long time and function well if it is properly looked after. Jackets and trousers are best stored hung up on proper coat hangers, leaving them scrunched up in the bottom of your pack will not do them any good. It will create creases and weak points in the fabric.

How to re-waterproof jacket. As already stated the DWR on a garment will eventually wash off and the micropores in the waterproof membrane will get clogged up with salts and oils from your body. So fairly regular washing and reproofing are necessary. In order to maintain the jacket the right washing liquid must be used, your normal washing liquid will ruin your waterproof and make it useless. A washing machine can be used and really gives the best results.

  1. Check the care labels for information. Empty the pockets of your jacket, do up the zips and fasten any straps or flaps.
  2. Clean off any visible debris or dirt with a brush or cloth. Never use an abrasive material to clean waterproof fabric.
  3. Ensure that there is no old washing detergent in the machine then add a liquid like Nikwax Tech Wash.
  4. Once the washing cycle is finished then use Nikwax Tx.direct Wash-in to recoat the DWR.
  5. You can also apply NIKWAX Tx.direct Spray-on which is designed to care for the water repellency of your garment. 
  6. When the cycle is finished, you can run a dry spin to try getting some of the excess moisture out of the jacket. This will prevent the moisture soaking too long in the fabric.
  7. Don’t tumble dry your jacket, as the heat can damage the waterproof coating. Instead, hang it up neatly in a cool, dry place until it is thoroughly dried through.

If you need advice about buying a waterproof jacket please give us a ring. We would love to talk to you. You can also browse our range for men and women.

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