Deck Treatments

Deck treatments that retain their appearance the longest are the ones that are the most like paint. Widely advertised clear finishes don’t provide long-term protection.

Lumber, like skin, doesn’t fare well when it’s left unprotected. The sun’s ultraviolet rays are always on the attack. Rain and sun alternately swell and dry wood, eventually causing it to crack and split. Moisture promotes the growth of mold and mildew. Even redwood, cedar, and pressure-treated wood can benefit from a protective coat. Our tests show that many clear deck treatments usually don’t offer more than a year of protection before their appearance has visibly degraded.


WHAT'S AVAILABLE

Major brands include Ace, Behr, Benjamin Moore, Cabot, Flood, Glidden, Olympic, Sherwin-Williams, Sikkens, Thompson’s, and Wolman. There are also many smaller, specialized brands

Opaque: These finishes hide the wood grain like a coat of paint and last longest. They are best for the typical deck made of pressure-treated pine, where grain isn't important. Opaque finishes, usually solid-color stains, hold up for at least three years. On the downside, some decks look better if the natural wood is exposed. Opaque finishes can also build up a film, especially after several coats. That film can peel, chip, and crack like a paint film. These finishes generally require more extensive and time-consuming preparation for refinishing, compared with semi-transparent or clear treatments.

Semitransparent: These finishes usually contain a small amount of pigment but let the wood grain show. This type is best for a deck made of expensive wood that you want to show off, such as cedar or redwood. This category includes a broad range of pigmented products, from little pigment to almost opaque, and all products that change the color of the wood after treatment. A semitransparent finish may need to be reapplied every two to three years.

Clear: These treatments contain water repellents but no pigment. They may also have UV inhibitors and wood preservatives to help protect the wood. They’re ideal for people who value the natural look of wood over the treatment's longevity, especially for decks built of exotic or premium wood species. Our years of testing have shown that most clear deck finishes don't last more than one year, deck refinishing an annual chore.

Price range: $15 to just over $40 per gallon.


HOW TO CHOOSE

Make an opaque treatment your first choice, as it retains its appearance the longest. After several coatings, however, an opaque finish can build up a film layer that may require more extensive preparation--such as scraping or sanding--for subsequent coats. Special precautions, such as the use of goggles, gloves, and respirators, are necessary when scraping or sanding pressure-treated wood due to the presence of toxic substances. Consider a semitransparent treatment if you want the wood grain to show. Be aware that if you choose a clear deck treatment, you’ll likely be doing the job over again within a year, though the preparation time is less than that needed for scraping and sanding.