2.5 Layer Hardshell Fabrics

2.5-layer Hardshell Fabrics

What are they and how do they work?
Traditionally, there have been 2 main types of construction used to make waterproof and breathable fabrics for use in outer hardshell garments. Well known brand names for these fabrics include Gore-Tex (Classic and XCR), eVENT, HyVent and Dri-Lite. These constructions are:
• 2-layer, where fabrics have the barrier (the waterproof and breathable coating or laminate) bonded to the inside surface of the outer woven 'face' fabric (typically nylon). A loose mesh or lightweight synthetic fabric is then usually used as a lining to protect the barrier from wear-and-tear and to make it feel more comfortable if worn next to the skin. This separate lining enables the garment to maintain a better 'drape', making it feel softer and more supple. It also looks a bit neater, as all the seam-sealing tape which has to be used on the seams of the outer fabric will be hidden under the lining.
• 3-layer, where fabrics have the barrier sandwiched directly between the outer woven 'face' fabric and a very thin knitted synthetic lining (sometimes called a 'scrim'). This lining still protects the barrier from wear-and-tear and makes the fabric feel more comfortable if worn next to the skin, but because it can not move independently, provides better protection to the barrier. Because the lining is very thin (it does not need to be as strong as an independent lining), 3-layer fabrics will dry out a lot quicker then 2-layer with a liner, and also be much less bulky.

2.5-layer fabrics (such as Gore-Tex Pac-Lite, HyVent-HT, H2No-HB) were developed to meet the demand for lighter and less bulky shell garments for use in milder weather, for more active sports (like running, adventure racing, etc), or for occasions when they are less likely to be actually worn (i.e. a stand-by layer carried in a rucksack). Their development and popularity has gone hand-in-hand with the development and popularity of softshell clothing (which allow greatly reduced use of waterproof shells). They are designed to give better performance than 2-layer garments without linings, but to be lighter and less bulky than 3-layer fabrics. They differ from 2-layer construction by utilising an extra coating on the inner surface of the fabric to help protect the main barrier from wear-and-tear and make it feel a bit more comfortable next to the skin (an attempt to make it feel less like 'sweaty plastic'). Some fabrics use a continuous protective layer (such as current 3rd generation Gore-Tex Pac-Lite), while others use a pattern of dots or other shapes (1st and 2nd generation Gore-Tex Pac-lite, HyVent-HT, H2No-HB).

What are their benefits?

Lighter, less bulky and quicker to dry than both 2-layer (with liner) or 3-layer fabric constructions.
More comfortable to wear next to the skin than unlined 2-layer fabrics.
More durable than unlined 2-layer fabrics.
Arguably better breathability than both 2-layer (with liner) or 3-layer fabric constructions, as there is less resistance (provided by additional layers of fabric) to moisture vapour transmission.

What are their drawbacks?

In use, breathability can appear to be in fact VERY poor, but this is due to several factors:
1. lightweight hardshell garments tend to be used in hotter, more humid weather, when fabrics can not transport moisture vapour through their structure nearly as well as in colder conditions (the bigger the difference between the humidity and temperature on the inside of the garment compared with the outside of the garment, the better the rate of moisture vapour transmission).
2. Fewer insulation layers are worn in warmer weather conditions, meaning there are less or even no layers of clothing in which moisture vapour can 'hide'.
3. Any condensation of moisture vapour on the inside of the fabric tends to be noticed the instant it forms (especially if being worn next to the skin over a T-shirt or shorts)- it is not 'hidden' by a lining as is the case with 3-layer or lined 2-layer garments.
Not as durable as either 2-layer (with liner) or 3-layer fabric constructions.

What does it cost?
2.5-layer fabrics are aimed at use in lightweight garments, which by their nature tend to be simpler in terms of design and features. This tends to mean that they are lower priced than heavier-weight shell garments of similar quality. Popular models at the moment include:
The North Face Venture Jacket - £79.99
The North Face Prophecy Pac-Lite Jacket - £149.99

How do I find out more?
See garment manufacturers websites for details of their own fabrics, otherwise see:

[ www.gore-tex.com ]

Or escape2 on Freefone 0800 0286 836

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