Western Red Cedar Finishing

Western Red Cedar is one of the few wood species that are just naturally at home outdoors. When properly finished, Western Red Cedar will gracefully weather for decades, even in the harshest environments. Its natural resistance to moisture, decay, and insect damage makes it the ideal choice for a surface exposed to sun, rain, heat, and cold all year round. Aboriginals have used cedar bark along British Columbia’s Pacific coast to make rope, clothing, and baskets for thousands of years. The logs were used for canoes, totem poles, masks, and long houses. 

The hallmark characteristic of Western Red Cedar, its natural durability, has preserved examples of native culture for more than 100 years. For centuries builders and artisans have valued Western Red Cedar for its natural beauty and durability. Cedar's unique aroma comes from naturally occurring thujaplicins in its heartwood. As many homeowners are too well aware, readying their deck for summer is all about tending to their "thujaplicins." These aren't exotic plants or endangered species. They are fragrant natural compounds that give western red its pleasant aroma and protect the wood from deterioration. These compounds resist moisture, are toxic to decay-causing fungi and insects, and preserve the wood to give it long-lasting appeal. Unfinished cedar has richly textured grain with colors ranging from mellow ambers, reddish cinnamon, and rich sienna browns. Its warm coloring is complimented by a uniform, fine-grained texture with a satin-like luster. Because cedar is virtually pitch and resin free, the wood easily accepts a range of finishes, from oils and stains to solid coatings and paint.

The choice of an exterior wood finish for cedar depends upon the desired appearance and the degree of protection required. Conversely, the amount of protection provided to the wood depends on the type of finish selected. They perform best when the coating is applied to all surfaces: face, back, edges, and ends. Cedar weathers over time to an attractive silver-gray patina with a certain architectural appeal; research chemists and wood scientists strongly recommend applying some form of protective finish to prevent surface degradation. Weathered surfaces provide a poor substrate for finishes. Even a few weeks of exposure will decrease cedar’s ability to hold a finish. Once the finish-wood interface fails, the coating will debond, blister, crack, flake, or peel. The longer the period of weathering, the more rapidly the finish may fail. Transparent, non-flexible, film-forming finishes such as lacquer, shellac, polyurethane, and varnish are not recommended for exterior use on cedar. Ultraviolet radiation will penetrate the transparent film and degrade the wood. 

Regardless of the number of coats, the finish will eventually become brittle, develop severe cracks, and fail. The natural coloration of newly milled cedar can most appropriately be retained by applying finishes that contain ultraviolet blockers. Finishes containing both effective mildewcide and ultraviolet protection are recommended. Since these finishes contain a low percentage of solids, they tend to be high maintenance. Penetrating oil-based stains or light-pigmented natural tones can also provide uniform color and protect the wood. I love Western Red Cedar and have used it for construction and art for over 50 years. I love its taste, smell, feel, sound, and colors. I would venture to say I have forgotten more about WRC than most folks know!