Does Redwood require Sealers?

Although Redwood has the highest decay and weather resistance of any commercially available softwood, its appearance and longevity can often be enhanced by use of penetrating oil sealers, especially in sites with high sun exposure.

Left untreated, redwood weathers to a dark "driftwood" grey only when exposed to rain. In sheltered locations, where oxidization is not subject to "rinsing" precipitation, redwood typically weathers to a dark brown.

The proud owner of a new deck invariably wants to preserve its "just-installed" appearance. In practice this is virtually impossible: even with annual application of a transparent sealer, redwood will eventually turn grey.

Redwood sealers can, however, provide several non-cosmetic benefits: water repellants slow down the seasoning process, fungicides reduce the growth of decay organisms, and UV inhibitors help prevent the breakdown of wood fibers by sunlight.

Types of Sealers

All finishes sold in California are required to meet strict and changing VOC (volatile organic compounds) compliance standards; brand performance can thus vary from year to year. Select a product that contains water repellants, fungicides and UV inhibitors. The California Redwood Association recommends several brands, including Penofin, Preservawood, TWP, Cabot and Olympic. Your choice among these will likely be made on the basis of color.  We carry the TWP in Clear, Redwood and Light Cedar.  It has passed the standards of our harshest  critics, our customer's.  No complaints so far in the fours years we have carried TWP! 

Pigments help sealers protect wood from UV rays; in general, the more pigment, the greater the UV protection. Truly "clear" products are usually reserved for interior use.

Solid body stains offer the highest level of protection, albeit at the expense of "naturalness." For fences in strong sunlight or high atmospheric pollution, they can be a practical solution, and have a maintenance cycle of six to ten years, whereas transparent stains last only a year or two.

Sealer Application

All sealers penetrate farther in dry wood. After installation of green or unseasoned redwood, wait four to six weeks to reduce surface moisture. (Green redwood two-by material may require up to two years to fully dry.)

Redwood Maintenance

Always keep your exterior redwood structures as clean and dry as possible. Remove debris between deck boards and under decks periodically.

Prior to application, clean the surface to be treated using a mild detergent and a non-metallic bristle brush. Rinse and allow to dry for several days.

Make provisions to collect run-off from planters or pots on a deck. A large plastic saucer can be easily fitted with a flexible 1/2" drain to direct excess water below the deck.