What fabrics are naturally waterproof without chemicals?

Several natural fabrics offer water resistance through their inherent fiber structure rather than chemical treatments. Boiled wool (loden) has been used for centuries in the Alps; the felting process compresses fibers so tightly that water beads off the surface while the fabric remains breathable. Lanolin, the natural oil present in wool, adds additional water repellency.

Waxed cotton is another time-tested natural waterproof fabric. Originally used in maritime clothing, cotton canvas is impregnated with wax (beeswax, paraffin, or plant-based wax) to create a water-resistant barrier. Ventile cotton, developed during World War II, uses an extremely tight weave of long-staple cotton that swells when wet to close the gaps between yarns, creating a waterproof barrier without any coating.

Alpaca fiber also has natural water-resistant properties due to its smooth, hollow fiber structure that does not absorb water easily. While none of these natural options match the absolute waterproofing of a PFAS-treated membrane in a downpour, they handle light to moderate rain effectively and are entirely free from forever chemicals. ONDU features brands like Paka and Arms of Andes that work with these naturally water-resistant fibers.