Waterproof jackets are one of the most important (and expensive) bits of outdoor kit. We’ve put a range of jackets through their paces during an increasingly wet Scottish spring and summer. All of them are made from layered fabric, basically an outer woven layer, usually treated with a water repellent coating, bonded to waterproof membrane (Gore-tex is the best known brand here; many of these products contain PFC/PTFE “forever chemicals”) – this construction is referred to as 2-layer and will normally have a liner to protect it. On 2.5-layer fabric an additional coating is applied to the membrane itself to…