Obtaining the maximum level of performance from your waterproof.
The correct layers under a breathable garment are essential for optimum performance. We recommend you wear a wicking base layer next to the skin. The type depends on the level of activity and the ambient temperature. Cotton or anything with a high cotton content should not be worn. Cotton will absorb up to ten times its weight in water or perspiration. Wool and silk for the same reasons are also poor materials for layers beneath breathable waterproofs.
If needed for extra warmth a fleece of suitable thickness will provide the ideal mid-layer.
To sum up it is essential to wear non-absorbent base layers that are designed to transport humidity away from the skin. It also important to remember that wearing too many layers will result in the production of perspiration at a greater rate than even the most effective underwear can remove it.
The weather conditions can also affect the breathability of the garment. During heavy rain when the ambient temperature is low, around +5°C to +10°C, waterproof garments suffer from cold bridging. In these conditions rapid build up of vapour condensation can result. Cold bridging is like a car windscreen in the same conditions. The screen needs forced ventilation to keep it clear. With a warm body inside a jacket and cold highly saturated air outside all conventional waterproof breathable fabrics struggle to cope because they cannot be force ventilated. Do not tighten draw cords unless essential to keep rain out. Allow air to circulate as much as possible.
In the same way garments will not breathe if the outer fabric becomes saturated. It is, therefore, essential that the water repellency of the outer fabric be maintained. See Washing and Re-proofing.
During periods of vigorous activity, especially when carrying a load or on steep terrain, the level of body perspiration will increase quickly and dramatically. Breathable fabrics do not prevent sweating. Only less clothing, less exercise or a lower ambient temperature will reduce sweating. If you have perspiration on the surface of exposed skin the body is producing moisture at a rate greater than the atmosphere can absorb it. No fabric can alter that.
Washing and Re-proofing.
Regular washing is essential for prolonging the life span of your garment. Dirt accumulating on or in the fabric wears the fibres and attracts water that blocks the breathable pores. This in effect will rapidly reduce the breathability of the fabric. Follow the manufacturers washing instructions using Nikwax Tech Wash. DO NOT USE DETERGENTS OR FABRIC CONDITIONERS. If possible cool tumble dry, otherwise hang to dry thoroughly and cool iron.
Re-proofing your garment is as important as regular washing. Although the fabric is treated with a water-repellent finish, it does not last for the life of the garment. When the repellent finish has worn off the surface fabric will rapidly absorb water reducing the breathabilty to zero. At this point reproof with Grangers or Nikwax spray or wash in re-proofer for breathable fabrics.
Do not leave your garment rolled or folded when wet. Hang to dry as soon as possible but not on a radiator.
Finally do not forget to maintain zips occasionally with Zip Lube.