Waterproof spray is a coating that seals out moisture. Sprays often are made with a silicone or fluoropolymer base, both of which are effective waterproofing ingredients that generally won't stain or leave a permanent unpleasant scent. Sprays are often used to waterproof clothing for outdoor use; camping equipment, such as sleeping bags; and outdoor furniture. Waterproof spray may also help fabrics repel stains from spilled food or drink. Carpets and furniture, for example, are commonly treated with waterproof spray to keep them from absorbing liquids that may stain them.

Two different types of waterproof spray are commonly used to protect fabrics: silicone and fluoropolymer. Silicone spray is most commonly used to protect indoor and outdoor fabrics. Silicone spray is relatively harmless, typically has no odor, and is generally easy to apply. Silicone is highly resistant to water; in addition to treating fabric, a silicone-based spray also may be used to waterproof brick patios, concrete pathways and wood decks. Silicone aerosol sprays are typically used for clothing and furniture applications. They help keep fabrics dry, though multiple applications may be required for the best protection from water. It generally is recommended to let items dry for up to 72 hours after application to ensure the spray has set completely.

Another type of waterproof spray is a fluoropolymer spray. These sprays are often used commercially to create waterproof outdoor clothing, though they also are commonly available in outdoor stores and through online merchants. These sprays can help keep clothing and outdoor equipment dry, but do tend to wear off over time and require a reapplication. Some manufacturers add Teflon to these sprays, which helps increase the ability of fabrics to resist water. The fluoropolymer spray is also commonly used in marine environments to protect fabrics on boats.

Indoor uses for waterproof spray include carpets and upholstered furniture. Most of the carpets and furniture sold today have been pre-treated, but it's usually best to ask to make sure. It also is recommended to reapply a waterproofing spray after steam cleaning any furniture, as that may remove previously applied waterproofing treatments.

Waterproof spray has many outdoor uses as well. Tents, sleeping bags, outdoor clothing, outdoor furniture, and patio umbrellas are a just few examples of applications for outdoor uses for waterproof spray. The sprays are typically very effective at waterproofing shoes and boots as well. Treating outdoor equipment several times a year with waterproofing sprays can help prolong its life and keep the user dry. In most cases, waterproof sprays will still allow items such as sleeping bags and clothing to "breathe" after application.