Those who work with cedar know that it does not warp, stays cool, will not rot and smells great. It is a natural alternative to chemically treated material, non-toxic and will not sag or bow over time, and with a little maintenance, it will keep its appearance for years. Initial finishing is the first step in that maintenance process.
Some manufactures suggest that unfinished cedar should be left to age from six to 12 months before applying any kind of finish. This method, over time, creates a distinguished silver-gray patina. However, the "Guide to Finishing Western Red Cedar" states that wood scientists and research chemists strongly advise that some protective finish be applied immediately to cedar to retard surface degradation. Even after a few weeks, unprotected cedar may not be able to hold a finish. Any applied coating at that time will blister, crack, debond, peel or flake. One suggestion is to apply a commercially prepared bleaching stain. This stain contains water-repellent plus additives and pigments. A few coats may have to be applied periodically to maintain that uniformly gray surface.
Transparent stains, although high maintenance, should contain ultraviolet blockers and mildewcide to protect the cedar yet preserve the natural color. They are water-repellent and also contain water-repellent preservatives.
Semi-transparent stains, latex or oil-based, work best on textured cedar and will last from two to four years. However, vertical grain cedar coated in semi-transparent finishes last one to three years before re-staining is necessary.
A finish composed of oil and water repellent preservative has an expected life of one to two years on both planed vertical grain cedar and textured cedar.
Paint will last up to 10 years on both vertical grain and textured cedar.
When applying a primer and a top coat, the light-pigmented, natural-toned finish can last three to five years on planed vertical grain cedar and from four to six years on textured cedar.
Flame retardants and wood preservatives also can be applied to all types of exterior cedar.
Finishing a cedar deck is necessary in order to protect it from the weather, temperature and other environmental factors. Most builders recommend using either a clear sealant, an opaque finish such as paint or color stain.
According to Consumer Reports Magazine, June 2010, 29 percent of the 1,000 deck owners surveyed nationwide never stained or sealed their decks, which resulted in dirt, fading, cracking, splinters and mold. Those deck owners who did seal or stain agreed that paint or other opaque finishes did continue to look good after three years, whereas clear or semi-transparent finishes did not last quite as long.
Natural weathering is attractive, but wood sealer, staining or painting is advised for all outdoor furniture and other cedar items such as posts, fencing and lattices. If cedar will be dug into the ground such as landscape ties, arbor or fence posts, preservatives are recommended.
Since interior cedar does not require as much protection as does exterior cedar, many more options for finishes are available. Applying bleached finishes give the interior cedar an aged look, and the cedar can be left to age naturally or clear sealer may be applied. Another option for smooth cedar implements a clear, penetrating wax that does not contain pigment. This wax brings out the luster of cedar's heartwood and sapwood tones. Non-yellowing, polyester, flat, high-gloss and semi-gloss clear plastic finishes can be used successfully on interior cedar. To darken cedar, Danish oil may be applied. Clear lacquers and varnishes can also be considered. To add color to the cedar, varnish stains, although more difficult to apply than waxes, are available in many tints and tones.