This article summarizes the types, application techniques, and expected service lives of various finishes on both preservative treated and untreated lumber.
The primary function of any wood finish is to protect the wood surface from natural weathering processes (sunlight and water), and to help maintain its appearance. How well the finish accomplishes this function depends on how the finish was formulated, particularly the type and amount of polymer (resin or binder), pigment (including extenders), solvent system, and additives used. Of these components, the type and amount of polymer and pigment most directly affect the mechanical properties and durability of the finish. Other factors that affect the durability of a finish include application technique, time between refinishing, extent to which the surface is sheltered from the weather, and local climate conditions.