For many purists, the only choices for decking are redwood or red cedar. Both of these western softwoods are prized for their rich color and natural beauty, and because they aren’t pumped full of chemicals or preservatives. Both species contain tannins and oils that make them naturally resistant to rot, decay and voracious insects.
However, the level of weather- and bug-resistance is directly related to the amount of heartwood in the boards. Heartwood grows closer to the center of the tree, and is relatively hard and very resistant to decay. Sapwood grows in the outer part of the tree, near the bark, and is softer and more susceptible to decay.
Award-winning deck builder Scott Padgett, of Idyllwild, Calif., uses redwood exclusively for decking. (“Composite decking has no soul,” scoffs Padgett.) The California Redwood Association (CRA)recommends using sapwood-streaked construction common or deck common redwood for decking, but Padgett prefers to use B-grade redwood, which is nearly clear of knots and contains mostly heartwood. For decking that’s 100 percent heartwood, the CRA suggests using construction heart redwood.
According to the experts at the Western Red Cedar Lumber Association, the four best grades of cedar to use for decking are (listed from most expensive and clearest, to least expensive and most knotty): architect clear, custom clear, architect knotty, and custom knotty.
In most regions of the country, redwood and cedar each cost at least three times more than pressure-treated lumber. For example, I recently bought an 8-ft.-long red cedar 2 x 6 and paid nearly $4 per linear foot–ouch! Both species are considerably less expensive on the West Coast. In California, for instance, a B-grade redwood 2 x 6 costs about $2.35 per linear foot.
Redwood and cedar require an annual power washing and coat of finish every three to four years. To protect the wood’s surface from the weather, and to help reduce checking (fine splits), apply a clear, water-repellent wood preservative.
To maintain the wood’s natural color, however, you’ll have to apply a stain. (Padgett recommendsSuperdeck semi-transparent stain.) If you don’t apply a stain, both redwood and cedar will eventually weather to a soft silvery gray.