Exterior wood stain is the best choice for decks, rough-finished wood (such as cedar shakes and log cabins) and any exterior project where you want the grain of the wood to show, sources agree. Unlike paint, which forms a thick, smooth film over the surface of the wood, experts say the best stains actually soak into the wood. While paint can peel and chip over time, stain simply fades as it ages. A coat of exterior stain can last from three to eight years, according to testing at the U.S. Forest Service. Contractors who stain houses and decks for a living say longevity depends on the type and quality of stain you choose, how well it is applied, how harsh your weather is and whether the stain is applied to a horizontal surface (such as a deck), which suffers more weather abuse than a vertical surface (such as a wall).
Like paint, stains come in either oil (alkyd-based) or latex (water-based) formulas. ConsumerReports.org editors say neither type performs better than the other in its most recent tests.
However, contractors who stain houses and decks for a living still have their preferences. Some, like Tim Carter, who posts his syndicated advice columns at AskTheBuilder.com, recommends only synthetic penetrating stains that contain no natural oils (such as linseed, tung or vegetable oil). "These natural oils are actually food for mildew and algae," Carter says. "To stop the organisms from feasting on sealants that contain natural oils, manufacturers have to add mildewcides and fungicides. Unfortunately, these chemicals are often water-soluble. Rain and snow can dissolve them and wash them away leaving a deck unprotected. That is one reason why many decks turn black or green in just six to nine months."
Pros commenting at DIYChatroom.com still prefer oil-based stains. One, who finishes decks to withstand the harsh weather of Cape Cod, says oil-based stains "stick longer and wear better" than water-based acrylic stains. A longtime custom finisher in Pennsylvania also recommends oil stains, saying any mold will wash off easily with the once-a-year cleaning you are supposed to do for a deck anyway.
One thing all of these experts can agree on is the Sikkens brand of stain. Sikkens Cetol SRD (Siding, Railing and Deck) Semi-Transparent Stain (*Est. $40 per gallon) is one of the most expensive stains in this report, but it's also the most universally praised: It's recommended by AskTheBuilder.com and professional contractors on Internet forums such as PaintTalk.com and DIYChatroom.com.
In addition to decks and exteriors, Sikkens Cetol SRD is approved for shakes, shingles, fences, boat docks, outdoor furniture and logs. It is a one-coat, translucent alkyd oil stain that contains linseed oil and comes in 10 matte colors. Sikkens stains are available at independent retailers.
Sikkens stains in general -- and the Cetol SRD stain in particular -- are repeatedly recommended on Internet forums by professionals who finish exteriors for a living. "I have received zero complaints on all my Sikkens products," adds a paint store owner posting on PaintTalk.com. AskTheBuilder.com's Tim Carter reports that Sikkens Cetol was one of the top five performers in a test of 30 semi-transparent penetrating stains at Earlham College in Indiana.
For a more opaque finish on vertical surfaces such as siding and fences, pros on Internet forums often recommend Sikkens Rubbol Siding Finish (*Est. $40 per gallon), a hybrid alkyd/acrylic stain. Although ConsumerReports.org editors and professional contractors say solid stains are more durable than semi-transparent stains, solid stains are usually recommended more for vertical surfaces (such as siding) than decks. Unlike semi-transparent stains that penetrate the wood, solid stains form a film on top of the wood -- somewhat like a thin paint -- and professional contractors report that this film can flake and peel just as paint can from a horizontal surface such as a deck.
Other brands of stain offer a warranty -- usually from three to 15 years, depending on whether you apply the stain to a vertical or horizontal surface. Sikkens offers no such guarantee, but is still strongly recommended by every source of exterior stain information in the Our Sources section of this report.
While Sikkens Cetol SRD Semi-Transparent Stain easily wins among semi-transparent stains, two solid stains also earn recommendations from ConsumerReports.org. One, Behr Deck Plus Solid Color Deck, Fence and Siding, is no longer available; it has been replaced by the new water-based Behr Premium Solid Color Deck, Fence and Siding Weatherproofing Wood Stain (*Est. $33 per gallon). Sears' Weatherbeater Solid Deck, Fence & Siding (*Est. $25 per gallon) is also water-based, and it's less expensive than Sikkens or Behr.
We found no references to Sears Weatherbeater stain on Internet forums frequented by professional contractors, including PaintTalk.com, PainterForum.com, ContractorTalk.com and DIYChatroom.com, or any other sources we consulted. However, pros on these sites provide plenty of opinions about Behr stain -- none of it very good. Several pros come to these forums for advice on Behr solid stain-related problems, saying it's thin, it peels quickly and it's hard to strip when it's time to re-coat. Their colleagues advise them to try a stain from a different brand, usually citing Cabot, Benjamin Moore and Sherwin-Williams. Of these brands, Sherwin-Williams Woodscapes semi-transparent and solid stains (*Est. $35 per gallon) and Cabot Solid Color Acrylic Siding Stain (*Est. $30 per gallon) are among the water-based stains tested by ConsumerReports.org, but the results are available only to subscribers.
Tim Carter at AskTheBuilder.com recommends Defy stains as his personal choice, and Defy Penetrating Water Repellent Wood Finish -- now Defy Original Synthetic Water Repellent Wood Stain (*Est. $36 per gallon) -- was one of the top performers in the college laboratory test of exterior stains that he cites. "I have personally used Defy on my wood porches over the years and have had great success," says Carter, who adds that Defy uses synthetic resins that don't feed mildew and algae as natural oils can. Some pros on PaintTalk.com report good results from Defy, but we found no reports of Defy's durability from professionals other than Carter, and it is not tested at ConsumerReports.org. Defy products are available through local and online dealers.
California Paints has its own line of exterior stain called Storm Stain. Its Storm Stain Linseed Oil Alkyd Decking Stain -- now Storm Stain Enduradeck Alkyd Linseed Oil Stain (*Est. $35 per gallon) -- was another top semi-transparent oil stain in the study cited by AskTheBuilder.com, but contractors posting on Internet forums offer varying opinions. Some at PaintTalk.com say they like Storm Stain, although they don't specifically say why, while one homeowner posting at DIYChatroom.com reports mildew problems with Storm Stain on his log house. However, we found little discussion of Storm Stain overall, and this stain is not tested at ConsumerReports.org. The same is true for another of the study's top semi-transparent oil stains, Wolman F&P Finish and Preservative (*Est. $25 per gallon). ConsumerReports.org tests the pricier Wolman DuraStain (*Est. $30 per gallon) solid and semi-transparent stains, but results are available to subscribers only. Wolman stains are widely available at chain and independent hardware and paint stores, and Storm Stain is available through independent retailers.
Another popular brand that gets only one recommendation from our sources is Thompson's WaterSeal. Owned by Sherwin-Williams, Thompson's WaterSeal offers clear waterproofers and oil- and water-based stains that are widely available at Lowe's, The Home Depot, Walmart and hardware stores. Joe Pullaro, a Florida painting contractor who gives advice at JoePullaroInc.com, recommends the Thompson's WaterSeal brand in general. However, it is not a well-liked brand at ContractorTalk.com or DIYChatroom.com. Some users say it looks bad or needs re-coating quickly. One writes, "In my opinion, the only thing Thompson's WaterSeal has going for it is a smooth marketing campaign."