Wood is a beautiful, sustainable material for homes, decks and marine/coastal environments. Wood, by its very nature, is a breathable material, so when used in construction and exposed to wind, rain and sun, it needs a level of protection to remain durable, resilient and looking good.
But before finishing any wood exterior, such as siding or a deck, it’s important to think about selecting a wood species that’s resistant to decay and insects, and one that can withstand the sun’s UV degradation. If possible, wood should also remain dry and experience minimal exposure to prolonged wetting cycles to avoid decay. For most of us, this is nearly impossible, and that’s why wood protection is crucial to the long-term beauty and durability of your home or deck.
Options and considerations
In the past, one approach for wood protection was to apply film-forming, semi- or nonpenetrating solvent and water-based formulas, which provide barrier-style protection. Many still believe the thicker the film, the better the protection and longer lasting maintenance cycles. But this comes at a cost.
The challenge is that when you use a nonpenetrating, water-based product or a high solids, solvent-based product, you build a film that darkens the wood, degrades clarity and becomes thicker with maintenance. The film traps moisture, reducing breathability, and can eventually result in peeling and blistering. In addition, these types of coatings often tend to be higher in volatile organic compounds (VOC) levels, which are chemicals that are emitted as gases from certain solids or liquids.
Today, you can opt for low-VOC, water-borne, alkyd finishes that penetrate wood rather than just sit on the surface; they’re also easier to maintain and are more durable. While superficial products will often peel and be difficult to maintain down the road, water-borne penetrating finishes wear more gracefully because they soak into the wood.
The goal is to keep the wood breathable. As you apply maintenance coats over the years to sustain beauty, clarity and protection, you don’t want to excessively increase the thickness of the finish and trap moisture inside.
Steps to long-lasting wood protection
When finishing wood, preparation is the key to success. First, clean the surface by pressure washing it, being careful not to damage it by getting too close. Then, sand thoroughly with 60- to 80-grit sandpaper.
It’s always good to test your wood finish on a piece of similar wood before starting your project. And wait for a day that’s dry and overcast, if possible, to ensure an even, easier application. For decks and other horizontal surfaces, use an initial coat of a deep penetrating water-borne finish for protection from within and then apply a satiny, glossier topcoat to protect against harmful UV rays, scraping and abrasion.
Selecting a color can be the fun part. But remember that the amount of color in the finish, or pigment loading, will affect the performance of the finish. The more pigment, the longer it will last, as good quality pigments, particularly finely ground iron oxides, such as trans-oxides or nano tints, provide excellent UV protection. Many homeowners don’t want to hide wood’s attractive and distinctive character. They can find clear or nearly clear coatings containing finely ground pigments that maintain clarity and enhance UV protection while offering a more natural look.
The good news is that today, consumers can also find “greener” wood finishes that also offer ease of application, durability and beauty. Low-VOC, water-borne alkyd finishes are far easier to maintain, as these coatings will tend to wear or erode gradually rather than peel.
In California, there are regulations governing VOC limits in architectural and industrial maintenance (AIM) coatings. Because of the state’s ever-changing regulations, many customers have been faced with the arduous task of stripping a no-longer compliant product to reapply a newly approved product. To find out what materials are recommended, seek advice from a licensed vendor that’s required to stay up-to-date on this sort of information.
Wood is an amazing material that we should all utilize more often. It’s strong, ecologically responsible (since it’s our only truly renewable resource) and creates an unparalleled finished look. With planning, preparation and reasonable maintenance, your wood deck, home or furniture can remain a sustainable surface for years of enjoyment.
John Barnes is owner of Sonoma Paint Center (www.sonomapaintcenter.com) with locations in Santa Rosa and Sebastopol. Sonoma Paint Center offers superior wood finishes developed to be “greener” than most and therefore remain VOC compliant even when regulations change.
