Waterproofs

Waterproofs refer to materials, coatings, and constructions designed to prevent water from passing through, protecting people, gear, and structures in wet conditions. They are distinct from water-resistant goods, which shed water only to a limited degree. Waterproofs are used in clothing, footwear, tents, sleeping bags, wetsuits, drysuits, and building envelopes such as roofs and basements.

Common approaches include waterproof membranes and coatings. Membranes such as expanded PTFE (ePTFE) and other polyurethanes provide a barrier against water while allowing some moisture vapor to escape, improving comfort. PVC and rubberized coatings offer durable impermeability, often at the expense of breathability. Many garments pair a microporous or laminated membrane with a durable water-repellent (DWR) outer finish to balance waterproofness and breathability. Seams are frequently sealed with tapes or heat welding, and waterproof zippers or gasketed closures are used in tents and bags.

Performance is assessed by standards and tests. Water resistance is often described by a water column or hydrostatic head rating, indicating the pressure a fabric can withstand before leaking. Building waterproofing relies on membrane or coating systems tested for water ingress, while garments may be rated for wearer comfort under varying rain intensities. Breathability is also considered, commonly expressed as moisture vapor transmission rate (MVTR). Maintenance typically involves reproofing DWR finishes and resealing seams; improper washing can degrade waterproofing.

Applications and considerations. Waterproofs protect outdoor gear, protective clothing, and electronic housings, as well as architectural structures. Environmental concerns include the use of certain waterproofing chemistries, such as PFAS, which have prompted regulatory scrutiny and shifting industry practices.