How to choose the right waterproof clothing and breathable fabrics

Working outdoors means exposure to all the elements. Thankfully, there is an ever-increasing array of workwear garments designed to protect you from snow, rain and wind – while allowing your body to breathe. But with more options available, how do you choose the right waterproof clothing and breathable fabrics for your environment and the type of work you do? After all, a lot of clothing is labelled as both waterproof and breathable.

Making the right decision is only possible when you understand how the clothing is constructed and can interpret the waterproof ratings and breathability ratings.

A quick definition of waterproof clothes and breathable fabrics
Waterproof jackets and trousers usually feature either a special water-resistant coating or membrane which stops water from penetrating the fabric. There are varying degrees of water resistance.

Breathable fabrics are designed to allow sweat to transfer from the interior of the clothing to the exterior. You may see this referred to as ‘wicking’. It means that, in principle, your body remains dry and the moisture can evaporate from the outer surface of the clothing.

Clothing can be both waterproof and breathable, but will usually perform better for one than the other. Which brings us to the clothing performance ratings.

Waterproof ratings for clothes

• 5,000mm: This rating qualifies for the term ‘waterproof’, but will offer little protection in a heavy downpour.
• 10,000mm – 15,000mm: Waterproof clothing with a rating within this range will give you protection even against heavy rainfall or snowfall. Prolonged contact with wet surfaces or pressure, though, will lead to the material absorbing water rather than repelling it.
• 20,000mm + : Clothing rated at 20,000mm or above should keep you dry even in sustained heavy rainfall where clothing is subject to pressure from a backpack, for instance, or kneeling or sitting on wet surfaces.

Breathability ratings for clothes

• 5,000 – 10,000g/m²: For general outdoor wear, you’ll find this breathability rating fine. If you start putting in much physical work, you may find the performance lacking.
• 10,000 – 15,000g/m²: Suitable for light labouring. If you’d usually build up a heavy sweat, the fabric probably won’t be breathable enough to keep your body dry.
• 15,000 – 20,000g/m² & above: At this breathability rating, you ought to be able to perform pretty arduous physical work without swimming in your own sweat!

Look for the EN 343 rating
It’s worth checking EN 343 rating on the CE label inside the clothing. EN 343 is a European Standard for protection against wet weather. It tests clothing for water prevention resistance and breathability, with each receiving a rating which will be seen on the label. 

Water Penetration Resistance

1. Minimum level of rain protection
2. Intermediate rain protection
3. Highest level of rain protection

Breathability

1. Not classified as breathable under EN343
2. Intermediate level of breathability
3. Highest level of breathability

If the CE label shows an EN 343 rating of 3 and 3, you know you’ve found the highest standard of clothing for all-round wet weather performance.

From looking at those ratings, it’s clear that not every coat, jacket or pair of work trousers will be suited to all wet or cold conditions, or to all types of work. We recommend buying a selection of wet weather workwear so that you have the right options for each task, at each time of year.

How can clothing be both waterproof AND breathable?
It seems to defy logic, doesn’t it? The only truly waterproof outer layers are wax or rubber. Working in a wetsuit is, obviously, impractical, and wax jackets and trousers can be heavy and cumbersome when you’re doing any manual work. This means that most of the workwear suited to farming, forestry and construction work is manufactured to balance a certain amount of water resistance against a certain amount of breathability. It’s all about the way the clothes are made.

Fabric construction types for outerwear
Clothes labelled as waterproof are usually made with two or three layers. Or, slightly confusingly, two and a half layers ... 

The outer layer is typically made of polyester or nylon, coated with a DWR (durable water repellent) treatment. This outer layer, sometimes called the face fabric, is not actually waterproof, but encourages most water to run off the surface.

Next is a membrane. It is often made of ePTFE (expanded polytetrafluoroethylene, the formula first discovered by DuPont and branded as Teflon). The ePTFE features lots of tiny holes which stop water getting in, while letting vapour out. The performance is adversely affected by sweat and oil, so the membrane is usually coated with polyurethane to protect it. 

Together, the outer layer and membrane are known as a laminate. That laminate is then attached to an inner layer: a mesh or fabric lining. The type of inner lining is generally where you see the performance difference for waterproofness and breathability. This is where the 2, 2.5 and 3-layer details matter.

2-layer fabrics (sometimes abbreviated to 2L)
A garment with a two-layer construction usually has a loose, comfortable fit. The outer layer and membrane laminate has a fabric or mesh liner attached. It hangs loose from the laminate and provides a certain degree of protection from your body’s oils and sweat. Two-layer jackets will be among the cheaper options available; they offer reduced performance in terms of water protection and breathability.

2.5-layer fabrics (sometimes abbreviated to 2.5L)
A 2.5-layer construction involves a similar outer layer/membrane laminate. The interior side then gets a sprayed or painted-on inner layer. This adds greater waterproof performance and keeps the clothing lightweight. You can get a closer fit, and because there’s less bulky material, the garment can be folded up quite small. Most standard raincoats have this construction. They are not as breathable as a 3-layer garment and won’t give you as much protection either.

3-layer fabrics (sometimes abbreviated to 3L)
These tend to have a firmer feel – they’re sometimes referred to as hard-shell. The inner layer is fully bonded to the membrane, which itself is often of a higher quality ePTFE. It’s a bulkier fit and feel than a 2.5-layer garment, but comfortable. Some breathability is lost, but the waterproof performance is as good as you can get in flexible, multi-use wearable workwear. 3-layer fabrics are the most expensive construction method.

When choosing your clothing, look out for the seams are sealed. These are the areas where one part of the garment is joined to another. Water can, over time, leak through the holes created when clothes are sewn together, so seams can be covered with a sort of waterproof tape. Fully taped seams involve covering all seams in the garment, for maximum waterproofing performance. Critically taped seams are just those which are most likely to get wet.

Looking after your waterproof clothing
A more advanced construction may mean better performance and a higher price, but even the best clothing only retains its performance if you treat it well. That means washing your waterproof workwear in strict accordance with the manufacturer’s guidelines. It is vitally important that you do not add conditioners or softeners to the wash cycle if your workwear features a membrane, because it can block the holes and impair performance. 

DWR treatments can also begin to fail with time, dirt, impact and multiple washes. Check with the manufacturer whether the clothing can be washed with a silicone-based solution (eg Nik Wax) to regenerate its water-repellent properties.

The brand of the membrane is worth investigating, too. eVent, for example, is recognised for being very breathable, but may need more frequent reproofing. GORE-TEX is known for both retaining body warmth well and excellent waterproofing performance.

Need to know more?
If you’re confused by waterproof fabric construction or still unsure which brand or type of clothing is best suited to particular work in particular seasons, don’t just guess! We’re here for a reason: contact a Kramp product specialist today for immediate, impartial advice.