Changing Nature of Wood Products—What Does it Mean for Coatings and Finish Performance?

By Charles Jourdain, Jack Dwyer, Keith Kersell, Douglas Mall, Ken McClelland, Robert Springate, Sam Williams

Most current recommendations concerning the application and performance of coatings and finishes on exterior solid wood substrates are based upon knowledge gained decades ago. Chapter 16 of the “Wood Handbook: Wood as an Engineering Material,”1 discusses the properties of wood and the interaction of these properties with wood finish systems.

A major part of this discussion is the result of research conducted by Browne2 on wood properties and paint durability during the 1950s and 1960s. Since that time dramatic changes have occurred to both the country’s timber base3 and to exterior wood finish formulations.

The shift from exterior wood products originating in the old growth forests of the Pacific Northwest (British Columbia, Washington, Oregon, and northern California) to products originating in the vigorous second and third growth forests of the northeastern, midwestern, southern United States and eastern Canada, as well as the Pacific Northwest, has accelerated in the past decade.

The species mix in almost all areas of the United States is vastly different today compared with 50 years ago.