The layer on layer principle

The primary function of clothing is to keep you dry, warm and protected. By dressing in multiple thin layers, you can easily adapt to changing weather conditions. This is known as the layering principle.

Outdoor clothing in the right materials

The layering principle works best when you choose the right materials. Wool is an excellent choice for hiking, as its performance is not affected even if worn for long periods without washing. It also keeps you warm when damp, has good breathability and rarely develops odour. Soft, non-itch merino wool can be worn directly against the skin.

Cotton is an example of a material that is not suitable for outdoor clothing. It absorbs moisture and becomes both cold and abrasive when wet. It’s therefore best to avoid cotton, especially for base layers.

Fleece is a synthetic fibre designed to be porous and airy. The air trapped in the material is warmed by your body heat, but the fabric itself does not generate warmth. Fleece works well when alternating between activity and short breaks, but is less suitable for longer stops. Air your fleece garments rather than washing them, as fleece can release microplastics in the washing machine.

Base layer – wicks away moisture

The layering principle starts with your base layer. The main function of this layer, worn closest to the body, is to move moisture and excess heat away to an outer, more absorbent layer.

Your base layer should keep you dry from the inside, even during intense activity. Merino wool, traditional wool and wool terry blends all retain warmth even when damp. Synthetic base layers – often called performance base layers – are also a good option. However, to maintain their function and avoid odour, synthetic garments need to be rinsed or washed frequently.

Mid layer – absorbs moisture

The mid layer is designed to absorb moisture from the base layer and move it away from the body. Wool works very well here. Pure synthetic materials cannot absorb moisture, but many performance garments still transport moisture outward by combining synthetic fibres with wool in the outer layer.

Outer insulating layer – provides warmth

The third layer provides most of the insulation and acts as a regulating layer. Put it on during low-intensity activity or breaks, and remove it during more strenuous movement. This helps you retain body heat when resting and avoid overheating when active. Common materials for this layer include fleece and wool.

Outer layer – protects against wind and moisture

The fourth layer is primarily designed to protect you from wind, precipitation and cold. It also plays an important role in regulating temperature. Garments in this layer should be roomy and protect exposed parts of the body.

A traditional anorak or a shell jacket that protects against wind, rain and snow should have a proper hood. It should be long and feature functional closures at the front, collar and cuffs, as well as drawcords at the waist and hem. By loosening these, you can vent excess heat; by tightening them, you retain warmth.

Fifth layer – extra insulation

The fifth layer consists of insulating garments for times when you are inactive. A hat, down jacket, vest or thick sweater can be very useful. Wool fibres generate warmth on their own, meaning they don’t rely on excess body heat to keep you warm. A wool sweater that may feel too warm during activity is therefore perfect for cold breaks.

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Materials in your shell clothing

There are advantages and disadvantages to both the classic anorak made from cotton blends and modern shell garments with waterproof membranes.

Tightly woven cotton or synthetic
A traditional anorak works best in dry, cold and windy winter conditions. It is flexible and doesn’t feel cold as long as it stays dry. It allows excess heat to escape, but will eventually let moisture in during prolonged wet weather. This type of garment works particularly well in sub-zero temperatures.

Synthetic shell garments with membranes
Synthetic shell materials consist of multiple layers laminated together to function as a single fabric. The middle layer – the membrane – is what makes the material waterproof. It has microscopic pores that allow water vapour to escape when you sweat, while being too small to let water droplets in from the outside. This makes multi-layer materials more resistant to moisture than cotton and suitable for year-round use.

However, what is an advantage in some situations can be a drawback in others – especially on cold and windy winter days. In such conditions, body heat can condense before it escapes through the garment, leading to moisture or even ice forming on the inside. One way to reduce this is to wear an insulating layer over the shell jacket, preventing it from cooling down too much and reducing condensation inside.

When choosing synthetic shell garments, opt for those free from PFAS (highly fluorinated substances), as these are extremely persistent and can accumulate in both humans and animals.

Accommodations near the adventure

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