Western Red Cedar
Western red cedar can be found from the Alaskan panhandle to the northern tip of California. It is a shade-tolerant coniferous evergreen that prefers moist soils and grows to great diameters and ages. Some specimens have been known to live well over a millennium. The wood contains thujaplicin, a natural oil that inhibits fungus growth and keeps rot at bay for an extended period.
Historically, native peoples of the Pacific coast prized cedar for its long lasting qualities and used wood and bark from cedar trees for most of their building needs. Evidence of cedar’s durability are the many cedar artifacts still in good condition today.
Western Red Cedar is one of the lightest commercial softwoods with an oven-dried density of about 21 pounds per cubic foot or about a third the density of water. This compares with Douglas Fir at 31lbs/cu. ft, Ponderosa Pine at 27, and Southern Pine at 34. Cedar’s low density enhances its insulative properties and makes for easy-to-carry deck panels.
Cedar is an excellent thermal insulator, which translates into a deck surface that won’t get hot on a sunny day. The conduction of heat in wood is directly related to its density. Low density woods like cedar have the highest thermal insulating value because they contain a higher proportion of cell cavities. In dry wood, these cavities are filled with air which is one of thee best insulators. That means that the minute you step on it, it gives up only its thinnest topmost surface heat to your feet. Because its a poor conductor, the rest of the heat locked up below that topmost surface takes its lazy time working its way past those air-filled cavities to where it can enter your feet, so it doesn’t feel hot. And being less dense, there’s not that much heat stored in the wood anyway.
Like all woods, Western Red Cedar will absorb or discharge moisture with changes in humidity. However, it has a very low shrinkage factor and will resist warping, twisting and checking better than any other coniferous wood. An 8″ unseasoned, fresh-off-the-farm western red cedar board will shrink only 1/4″ to its final state.
Cedar is a naturally durable species. Although cedar is ideal for decks, its performance is enhanced when protected by an appropriate finish. It’s free of pitch and is the best of the softwoods for accepting paints, stains, oils and other coatings.
Due to widely differing preferences in treatment options and colors, we do not treat our cedar decking. However we do recommend Rymar Wood Sealers. http://www.rymarindustries.com/ For a detailed discussion, see Finishing Western Red Cedar (800K pdf) published by the Western Red Cedar Lumber Association. http://www.wrcla.org/pdf/WRCLA_Guide_to_Finishing.pdf