How to Finish Cedar
Paint - provides the most surface protection against weathering and wetting by water while providing color and concealing some of the wood's characteristics. Although paint can reduce wood's absorption of water, paint itself is not a preservative. Alkyd oil-based primers usually offer the best shield against discoloration by water-soluble extractives. Latex paint, particularly 100% acrylic formulations, remain more flexible with age and are better able to accommodate dimensional changes by stretching and shrinking with the wood.
Solid-Color Stains - are opaque finishes with fewer solids than paint. Available in a wide spectrum of hues, solid-color stains obscure the woods true color but allow some of the natural characteristics and texture of cedar to remain. Solid-color stains perform best on textured surfaces. They are non-penetrating and, like paints, form a film. A stain-blocking primer should be applied first, followed by a 100% acrylic latex-based top coat.
Water-repellents and water-repellent preservatives - may be applied to cedar used above ground. These formulations reduce water absorption in the short term. The addition of a fungicide that inhibits the growth of mildew and decay fungi will further increase wood's durability. A low-wax-content water-repellent preservative applied to newly-milled cedar as a single-coat pre-treatment before painting may help reduce discoloration caused by bleeding of water-soluble extractives.
Semi-transparent stains - may be latex or oil-based. The semi-transparent nature of the stain, due to its low solids content, does not block all ultraviolet radiation and some will reach the wood's surface. Latex stains do not penetrate the surface and are not as durable.
Note: Transparent, non-flexible, film-forming finishes such as lacquer, shellac, urethane, and varnish are not recommended for exterior use on cedar. Ultraviolet radiation can penetrate the transparent film and degrade the wood. Regardless of the number of coats, the finish will eventually become brittle, develop severe cracks and then fail.