Transparent Stains
These stains do not alter the appearance of the cedar. They only slightly modify the color (tone) of the wood. Transparent stains are similar in composition to semitransparent stains, but they contain fewer pigments. Transparent stains formulated with a fungicide that inhibits the growth of mildew and decay causing fungi will further increase the wood's durability. Waterborne and solvent borne formulations are available; however these unpigmented or lightly pigmented finishes provide limited protection against the sun's ultraviolet light and moisture related damage. As such, they require frequent refinishing. Transparent stains are, however, easily refinished with minimal surface preparation.

Transparent Stains
Solvent borne oil-based semi-transparent penetrating stains penetrate the wood surface, are porous, and do not form a surface film like paints. These finishes are the best choice for Western Red Cedar, which is fully exposed to the weather, when a natural look is desired. Although these stains can be used on both smooth and textured Western Red Cedar, they will perform much better and last longer when applied to a textured surface. These stains contain pigments which provide color - including cedar tones - and greatly increase the durability of the finish by protecting the cedar surface, to some extent, from the damaging effects of the sun's ultraviolet rays. Service life on siding applications may vary from 3-6 years depending on the cedar surface texture, quantity of stain applied, and the intensity of the sunlight on the wood surface.

Latex semi-transparent stains are similar in appearance to the solvent borne stains; however their look is achieved by the formation of a thin film with little penetration. This film is often not thick enough to provide the same durability as solvent borne stains and tends to degrade by flaking from the wood's surface. Refinishing cedar that has been coated with a latex semitransparent stain may require more substantial surface preparation. Currently, efforts are underway by many stain manufacturers to develop water-borne stains that penetrate cedar. However, to date, moderate success has been experienced in duplicating the properties of traditional oil-based, solvent borne, stains. As increasingly restrictive environmental standards reduce the availability of solvent borne stains, ongoing research suggests that penetrating, erodible latex semi-transparent stain finishes for cedar will be available in the near future.

Note:
Transparent, non-flexible, film-forming finishes such as lacquer, shellac, urethane, and varnish are not recommended for exterior use on Western Red Cedar. Ultraviolet radiation can penetrate the transparent film and damage the wood. Regardless of the number of coats, the finish will eventually become brittle, develop cracks in the coating film and then fail.