Established in 1986 Trekitt is family owned and run. We have always been driven by our passion for wild places and mountains and have enjoyed sharing those experiences with our customers for over 30 years.

Trekitt provides top quality equipment and clothing for mountaineers, hill walkers, climbers and travellers and has grown over the years to cater for a wide range of outdoor activities. We hold large stocks of specialist clothing and equipment from the worlds best brands backed up by our award winning customer service.  We are more than a shop, we are a service for adventure, we fully understand that to get the most from your passion you need the best kit that is fit for purpose and suits you personally.  We offer expert boot and rucksack fitting services in our Hereford shop and are always happy to discuss your equipment needs, so just call us.

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51 Eign GateHereford Herefordshire HR4 0AB
   24/01/2018 12:39:13

Which Outer Layer Should You Choose?

Your waterproof, or shell layer, consists of the outer garments of your layering system, commonly a jacket and over-trousers. The jacket is often the piece of outdoor kit that people buy first. After all, it rains a lot in the UK and who wants to get wet? As well as keeping out the rain, your shell jacket must also allow heat and moisture (sweat) that you have created to escape, or breathe, to the outside to avoid overheating or the heat robbing effects of evaporative cooling (see my blog on the layering system for more info). A well designed and reliable waterproof and breathable shell is essential to keep you safe and comfortable when the weather turns nasty or when you just need another protective layer if you’re starting to feel cold and uncomfortable. This article is designed to explain some of the different types of materials and construction methods used by major brands and to help you make the right choice for your chosen activity.


What is “waterproof”?

It is in fact incredibly difficult to make anything waterproof, given enough pressure water can penetrate just about anything, even concrete! So, when jacket manufacturers talk about a garment being waterproof they are referring to the amount of water the fabric can withstand in real-life scenarios before it leaks. The Hydrostatic Head (HH) test is the most common measurement for defining how “waterproof” a fabric is. This is a test in which a tube of water 1" in diameter is filled with water with a sample of the fabric held taut underneath. This is monitored over 24 hours to see how many millimeters of water the fabric can withstand before leaking. When the fabric leaks, the mm is noted as a score, and this is known as the ‘hydrostatic head’. To meet the British standard for 100% waterproof, fabric must be able to withstand 3 PSI, or 1500mm HH, of pressure. To give you some idea of how well modern waterproof fabrics perform examples such as Gore-Tex Pro have a HH around 40,000mm.

It’s not only the fabric itself that makes a jacket “waterproof”. To be classified as 100% waterproof all the seams that hold the garment together must be seam sealed. Basically, when a garment is stitched together the needle makes millions of tiny holes in the fabric which could potentially let water in. To seal up those holes a special tape is bonded to the back of the seam to make it completely waterproof. Modern construction techniques now use micro-taping to reduce the overall weight of the jacket (thick taping is heavy) and to improve breathability (seam tape doesn’t breathe). The most efficient jackets are designed to minimise the number of seams to maximise the performance of the jacket.

Screen Shot 2018-01-24 at 11.15.14

Above: Arc’teryx’s micro-sized taping on the Beta LT jacket.

What is “breathable”?

Breathability is the measurement of how much water vapour can pass through a given fabric over a defined period. There are many tests used by brands, who often choose one that makes their fabric look good, but the indication of breathability used most commonly is the “Moisture Vapour Transfer Rate (MVTR) test which provides a measurement of grams/metre/day. This is a very hard measurement to take and there are so many variables in jacket design that the figures can be misleading. We’d therefore recommend that they be used as a rough guide, or as a comparison between models. There is no minimum “standard” for breathable, but high-performance fabrics such as Gore-Tex Pro and eVent DVexpedition have an MVTR of 25,000 g/m2/24hrs.


Manufactures use different construction methods depending on the intended use of the jacket, the performance characteristics, or the even the perceived budget of the customer. The number of layers of fabric and waterproof technology almost always describe the garments construction and can be broadly split into the following categories:

· 2 layer

· 2.5 layer

· 3 layer

On first appearance waterproof jackets look like they are just one layer of fabric, but they are usually a laminate construction of an inner layer, a waterproof layer (either a coating or membrane) and an outer layer. How these layers are stuck together determines how it is categorised.

All three categories have an outer, or face, fabric which is coated with a chemical Durable Water Repellent (DWR, see below) to stop the face fabric from wetting out (absorbing water) and its main job is to protect the waterproof layer from abrasion and contamination to prolong the life of the garment; it also determines the aesthetics of the garment.

The middle layer is where the magic happens and is the layer that makes the jacket waterproof and is the major factor in determining how breathable the jacket is. Most commonly this layer is bonded directly to the back of the face fabric and can be either a coating or a membrane.

The inner layer protects the waterproof layer from internal abrasion/damage and helps to maximise breathability by protecting it from oil/grease/sweat contamination. This layer has a big effect on how breathable and comfortable the garment will be.

Screen Shot 2018-01-24 at 11.10.12

Above: Arc’teryx’s Beta LT showing it’s DWR capabilities.

3-Layer construction

Often referred to as “hardshells”, 3-layer fabrics use a laminate, or sandwich, construction of all three layers. So, the face fabric, waterproof layer and lining are all stuck together to create a durable and hard-wearing fabric. This type of construction is commonly used for jackets that are expected to have a hard life and face continuous exposure to extreme weather. Modern fabric technology and construction techniques have transformed this category from being known as stiff, heavy, and cumbersome to become lightweight, highly breathable and incredibly hardwearing. The modern laminated fabrics used in hard-shells represent the top of the line waterproof/breathable technology available and are primarily designed for the rigors of mountaineering and winter climbing. However, they are incredibly versatile and can be used all year round in almost any condition and in any environment. If you’re looking for one jacket to do everything, then this category offers the best choice.


2.5 Layer construction

2.5-layer fabrics, on first inspection, look very similar to 3-layer fabrics but are usually lighter and more flexible. They are made by bonding the waterproof layer to the face fabric in the same way as a 3-layer construction, but the inner layer is made up of a micron thin coating to protect the waterproof layer from wear and contamination. This layer is often painted on to cover the entire middle layer or sometimes appears as a printed pattern, which is why it's considered as a half layer.

Jackets with a 2.5-layer construction offer similar breathability to 3-layer jackets, however, they can feel clammy on the inside as the inner layer is not as effective as absorbing the moisture created by the wearer. They do not offer the same levels of durability and abrasion resistance, but are often lighter, have a compact pack size and cost less than the more robust three-layer hard-shells. They are suitable for a wide range of activities and conditions; their breathability makes them appropriate for warm weather use and if they are sized appropriately you can add insulating layers when it gets chilly.

2 Layer construction

These fabrics bond the waterproof layer to the face fabric as above, but leave the inner layer loosely hanging on the inside. This inner layer is often made from a light mesh or soft tricot fabric to protect the waterproof layer and to provide comfort for the user. They do offer good levels of breathability as less “glue” is used to stick the layers together and they often feel softer and more pliable. But, they can be bulky and heavy and are best suited to occasional light use and should not be considered for serious outdoor pursuits.

The Outer Layer – or Face Fabric.

This is the layer that provides the first line of defence from the elements and from the environment. Depending on your chosen activity and how hard wearing you need your jacket to be, it is commonly made from either Polypropylene (Nylon) or polyester. Nylon offers the best defence against abrasion and regular wear and tear but can be a bit stiff and noisy. Polyester is generally softer and quieter and offers a cheaper alternative for those less active users. The “denier” of the fabric will also determine its durability, this is an indication of the thickness of the fibres themselves and the fabric overall; the higher the number the higher the durability.

As described earlier, the face fabric is also treated with a Durable Water Repellent (DWR) which is a chemical treatment applied by the manufacturer to the exterior fabric. The DWR’s job is to maximise breathability by keeping the external face fabric as dry as possible and to prevent it from becoming saturated. If the face fabric wets out (becomes waterlogged) all the warm, moist air that you’ve created will condense on the lining and make you feel cold, clammy, and uncomfortable or even give the illusion that the jacket is leaking.

All waterproof fabrics are treated with a DWR as well as most water-resistant fabrics found on insulated and softshell jackets. Over time and with regular wear and tear the DWR will diminish so it’s important to wash and re-proofing your jacket regularly to maximise its performance (see care and maintenance section here).


Waterproof Membranes & Coatings

There are two main types of waterproof layer technology, a physical membrane laminated (stuck) to the face fabric or a coating applied to the back of the face fabric. Membranes are made from a micron thin layer of either expanded polytetrafluoroethylene (ePTFE) or polyurethane (PU) and coatings are mostly made from a thin layer of PU. Both systems are completely waterproof, but the big difference comes in how breathable they are. There are two ways in which a membrane or a coating breathes, it’s either microporous (full of tiny holes), or hydrophilic (water attracting).

Microporous Membranes

Microporous membranes are literally full of tiny holes that are so small that water droplets can’t get in but moisture vapour and sweat can get out; making them highly “breathable”. The two most commonly used in waterproof clothing construction are Gore-Tex and eVent. Both provide reliable and durable protection from the elements and have become the preferred choice for outdoor enthusiasts because they just work extremely well.


Gore-Tex is the oldest and most widely known microporous membrane and has become the dominating brand of the waterproof-breathable fabrics world. On a very basic level, Gore-Tex is a 0.01mm thick, ePTFE membrane stretched out to an extremely specific dimension. This creates 9 million pores (holes) per square inch that allow the membrane to breathe whilst remaining completely water and windproof.

Gore-Tex comes is available in different versions to suit varying activities, budgets and performance levels, each version has slightly different construction methods that give unique performance characteristics. Gore-Tex insist on stringent manufacturing standards from anyone who uses their fabric, brands have to meet these requirements to gain a production licence so you can be sure that each and every garment, from whichever brand, has been made to the very highest standards. Gore also offer their “Guaranteed to Keep You Dry” promise for all their products, so if you buy a jacket with a big black Gore label on it you can be sure that “If you are not completely satisfied with the waterproofness, windproofness or breathability of your product, then we will repair it, replace it, or refund your purchase price”.


PACLITE is Gore’s 2.5-layer construction. It’s made up of the Gore ePTFE membrane laminated to a lightweight face fabric with a micron thin layer of PU as the inner layer. Warm air and moisture hit the PU layer and turn to liquid which passes through PU layer to be wicked to the face fabric through the ePTFE's pores, where it evaporates. This process works best when the temperature and humidity inside the jacket is higher than the temperature and humidity outside. But if you’re working up a good sweat in mild conditions you can overload the system and condensation will build up inside the jacket. Because of the nature of the PU lining the condensation is hugely apparent as water droplets and lead to discomfort and the impression that the jacket is leaking. However, PACLITE does provide an extremely lightweight and packable construction making it the ideal solution for hiking, cycling and other sports where weight and space are critical.

Gore-Tex C-KNIT

This is Gore’s classic three-layer construction and is made up of the Gore ePTFE membrane laminated to varying face fabrics (depending on the anticipated end use). To stop the ePTFE membrane's pores becoming clogged with oils and dirt a micron thin oleophobic PU layer is added to the laminated sandwich, effectively covering the ePTFE membrane. Finally, a “knitted” lining material is added to provide next-to -the-skin comfort and to absorb any moisture that has not yet passed through the membrane; keeping the inside feeling much drier and comfortable. Garments made from Gore C-KNIT provide reliable performance across a wide range of mountain activities and can with stand the wear and tear associated with carrying heavy packs and multi-day outings.

Gore-Tex Active

Gore-Tex Active was developed to provide the ultimate lightweight, breathable, and waterproof material. This three-layer construction is made up of the Gore ePTFE membrane laminated to very lightweight face fabrics, then a lightweight the lining fabric is incorporated into the thin oleophobic PU layer. This construction improves breathability as moisture can get to the membrane more quickly and reduces weight. Gore Active fabrics are perfect for highly aerobic, done-in-a-day activities, even in bad weather. They are lightweight and soft, with excellent next-to-skin comfort thanks to their increased breathability. However, due to their lightweight construction we wouldn’t recommend Gore Active products for more arduous activities such as mountaineering or for adventures involving the use of heavy rucksacks over multiple days.

Gore-Tex Pro

Gore-Tex pro is the latest development from Gore and has revolutionised wearer comfort and garment performance. The three-layer construction is made up of a unique 100% ePTFE membrane that eliminates the need for the oleophobic PU layer making it incredibly breathable as moisture can pass directly into the pores of the membrane. This is then bonded to durable and robust face fabrics and lined with a thin, low denier Gore micro grid woven fabric. This ultra-smooth lining enhances breathability, reduces weight, and allows the garment to glide over layers making it incredibly comfortable to wear. Garments made with 3-layer Gore-Tex Pro fabric are durably waterproof, windproof, and extremely breathable. They combine comfort with reliable weather protection, even during extended activities in extreme weather. Made to meet the high demands of mountaineers, mountain guides and serious outdoor enthusiasts, garments made with 3-layer Gore-Tex Pro fabric are engineered with added durability to withstand abrasion in rugged environments while protecting against extreme and unpredictable conditions with frequent work-rest cycles.



eVent is very similar in design to Gore-Tex and is also an ePTFE based material. It was originally designed for industrial air filters before discovering it would make a fantastic waterproof breathable fabric. Much like Gore-Tex, eVent fabrics are made up of a laminate construction depending on the intended use. However, the big difference is that eVent have cleverly invented a way to completely remove the oleophobic PU layer from the membrane (much like Gore-Tex Pro). eVent uses a secret propitiatory coating that protects the individual fibers without clogging the pores. The result is a more breathable, air permeable ePTFE membrane that doesn’t rely on the temperature differential to stimulate breathability; it just breathes all the time!

eVent DVstorm

eVent DVstorm is a very lightweight waterproof and highly breathable 3-layer construction that provides protection from the elements. The eVent ePTFE membrane is laminated to very lightweight face fabrics and lined with super-lightweight 10 denier backers to reduce weight and improve breathability. They are lightweight and soft, making them perfect for walking, cycling or even trail running. However, due to their lightweight construction we wouldn’t recommend DVstorm products for more arduous activities such as mountaineering or for adventures involving the use of heavy rucksacks over multiple days.

eVent DValpine

DValpine was the original air permeable, 100% waterproof membrane launched by eVent way back in 1999. This three-layer laminate construction is made up of the eVent ePTFE air permeable membrane laminated to varying face fabrics (depending on the anticipated end use). A soft yet durable lining material is added to provide next-to -the-skin comfort and to absorb any moisture that has not yet passed through the membrane; keeping the inside feeling much drier and comfortable. Garments made from eVent DValpine provide reliable performance across a wide range of mountain activities and can with stand the wear and tear associated with carrying heavy packs and multi-day outings.

eVent DVexpedition

eVent developed the DVexpedition membrane to compete directly with Gore’s new Pro membrane for serious end users who give their kit a real beasting in extreme conditions. The three-layer construction is made up of the eVent air permeable ePTFE membrane laminated to durable and robust face fabrics and lined with a new smoother and more durable grid woven fabric. This ultra-smooth lining enhances breathability, reduces weight and allows the garment to glide over layers making it incredibly comfortable to wear. As the name suggests, DValpine products are designed for expeditions, high-altitude mountaineering, climbing and just about any other mountain related activity you can imagine.

Polartec NeoShell

Polartec, who are best known for making the best fleece fabrics, developed their NeoShell membrane to provide an engineering breakthrough for waterproof breathable fabric technologies. The NeoShell is made in a completely different way to ePTFE membranes like Gore-Tex and eVent. Polartec developed a process called electrospinning, which involves dissolving a plastic in a solvent and firing the solution at a collector until a film builds up, a bit like a candy floss machine. This creates a fibrous, stretchy membrane that is waterproof, 99.9% windproof, and air permeable to allow incredible levels of breathability and temperature management. This highly aerobic air permeability provides the unique benefit to function as a durable protective shell with advanced wicking capabilities to keep moisture vapor moving away from your core. NeoShell fabrics are constructed much like Gore-Tex and eVent as a three layer laminate, but is uniquely laminated to soft and stretchy fabrics to maximise the performance of the membrane. These garments blur the lines between softshell and hard-shell garments and provide users with garments that cope superbly with highly aerobic activity in extreme conditions. The only issues with NeoShell is that the membrane will degrade over time and lose some of its waterproofing qualities. (but never less than 5000mm)

Hydrophilic Membranes and Coatings

Rapid advances in technology mean that modern PU fabrics are quickly catching up to the performance levels of ePTFE membrane fabrics like Gore-Tex and eVent. The PU acts as the waterproof layer and is made from a solid hydrophilic (water-loving) film or coating with no pores. They are impermeable to air (windproof) and have good breathability depending on the thickness of the PU, the overall design of the jacket and the sophistication of the technology applied. The breathability occurs by water molecules passing along molecular chains from one side of the PU to the other. The water molecules are first adsorbed to the inner surface of the hydrophilic material then they move to the next molecule along; this process continues throughout the thickness of the hydrophilic material until it escapes through the face fabric. Temperature greatly affects hydrophilic breathability; optimum performance is achieved just above freezing. The biggest advantages to garments featuring Hydrophilic waterproofing is that they to be lighter, cost less and can be constructed with stretch for comfort and freedom of movement.

The majority of “own-branded” waterproof materials employ Hydrophilic technology as it is usually cheaper and more widely available; for example, Dri-Lite from Mountain Equipment.

Pertex Shield +

Pertex are widely known for developing high performance fabrics that are used by many brands across a wide range of products. Pertex technologies are amongst the lightest, most reliable, and most durable on the market and with a long-established heritage of staying true to its British roots.

Pertex Shield + is a hydrophilic membrane waterproof construction available in 2.5-layer and 3-layer laminates. Used widely by Rab in their more athletic garments, it provides complete waterproofing with good levels of breathability. Lighter weight 2.5 layer versions offer excellent levels of breathability with miniscule pack size whilst the more robust 3 layer versions are more durable and breathable.


Care and Maintenance

So now you’ve got all the information required to make an informed choice about which outer layer you’re going to choose, it’s equally as important to know that the life of your garment, and their continued performance, will hugely depend on how well you look after them. Let’s put it this way; you wouldn’t buy a Ferrari and never have it serviced.

Waterproof, breathable clothing has a durable water-repellent (DWR) finish applied to the face fabric during the manufacturing process. The DWR forces water to bead up and roll off the surface therefore preventing the fabric from absorbing moisture (wetting out). If the outside of your jacket is soaked in a layer of cold water, the warm damp air within can’t escape and will condense on the inside. This makes the jacket feel cold clammy and can make you think that it’s leaking. The DWR finish is not permanent and needs to be maintained and revitalised to optimise performance.

Therefore, it is essential that your garments are regularly washed and re-proofed; after all they are a piece of clothing and you wouldn’t wear your jeans for three years without washing them. Waterproof jackets should be cleaned regularly with Nikwax Tech Wash; I wash my jacket about once a month, or more often if it gets really filthy. Regular washing with Tech Wash will maintain the DWR for longer and remove salts and oils that can contaminate the fabric, plus it will keep your lovely jacket clean and smelling fresh. Washing can be done in a machine according to the manufacturers care guidelines (on the internal label). First, clean out any detergent and conditioner residue from the machine dispenser, add the required amount of Tech Wash and away you go. Hand washing is also suitable but be sure to rinse the garment well. Liquid detergents and fabric softeners must be avoided, they contain components that adhere to the fabric's fibers increasing the likelihood of wetting out.

After regular wear and tear you’ll notice that the garment is wetting out, it’s now time to renew the DWR. Nikwax TX Direct will re-instate a long lasting DWR to completely rejuvenate your jacket. Re-proofing can also be done in the machine once a garment has been washed. Just add the TX-Direct and use the same programme you used for washing. You can also use the spray-on product on a damp garment that has just been washed.

A well cared for and clean jacket will function better and last longer than a neglected, dirty one. First off, be kind to your jacket. Whether you stuff the jacket into its pocket or roll it away into its hood, you will prolong the performance of the DWR treatment. The less abrasion and abuse the face fabric receives, the better.

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The product I bought was competitively priced. The video demonstration of the product assisted me in my decision to purchase the item and was very informative, as it showed all of the features and the fit. I chose "click and collect" which was an efficient and quick process. I would definitely shop here again.

Amanda  •   19 Jan 2019.

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