As reviewed by DeckStainHelp.com on criteria including appearance after initial application, ultra-violet graying after two years, wear and tear, ease of application and color darkening, TWP, Armstrong Clark and Defy deck stains rate most highly. Among the most popular deck stains on the market, Behr and Thompson's products stand out. In at least one independent simulated weathering test, Behr's waterproofing wood stain was top-rated. Thompson's waterseal deck and house stain is also highly rated, though not as effective against mildew.
TWP's stains are the only deck stains listed on the Environmental Protection Agency's registry as exterior wood preservatives. For states in which the amount of volatile organic compounds allowed in decking stains is regulated, TWP's 1500 series and Armstrong Clark wood stains are recommended. Both are oil-based stains, known for performing better against water penetration than water-based stains, though Consumer Reports testing has not evidenced a significant difference in durability.
In addition to water- and oil-based stains and variations across manufacturers, there are three types of deck stains: solid stains that cover the wood grain and are the most durable, clear stains that allow the wood grain to show, but usually require yearly refinishing, and semi-transparent stains that include some properties of both.
According to professionals, it is difficult to identify the best deck stain because the performance and regulations vary depending on the state in which the deck is located, the daily amount of sunlight, the type of wood and whether mold and mildew are potential issues.