Overview

John Buddy Showalter

American Forest & Paper Association
Washington, D.C.

Thomas G. Williamson

APA The Engineered Wood Association
Tacoma, Washington

Wood is the only renewable source for building materials. It comes from forests that are continually being replanted as they are harvested. This practice ensures a plentiful supply of wood for construction and for a myriad of other uses.

Compared to other building materials, wood has a very high ratio of strength to weight. This makes it very economical for use in all types of construction. Wood also has an aesthetic quality and natural warmth unequalled by other building materials.

Wood has inherent characteristics with which construction users should be familiar. For example, as a consequence of its biological origin, it is nonhomogeneous. Also, properties of pieces of wood from different species of tree may be considerably different, and even properties of pieces of wood from the same tree may differ. In the past, determination of engineering properties depended heavily on visual inspection, keyed to averages, of wood pieces. Research, however, has made possible better estimates of these properties. It is no longer necessary to rely so heavily on visual inspection. Greater accuracy in determination of engineering properties has been made possible by mechanical grading procedures.

Improvements in adhesives for wood also have contributed to the betterment of wood construction. These advances in adhesion technology combined with a desire to utilize more efficiently available wood-fiber resources have led to increasing use of such products as oriented strand board (OSB),...