Holy sheet! Plywood, the venerable product that has helped house generations and led to the development of engineered wood products we rely on today, celebrated its 100th anniversary this spring.

Surprisingly, plywood didn't begin as a construction product. According to a historical timeline from APA-The Engineered Wood Association, softwood plywood was first invented in 1905 by wooden box manufacturer Portland Mfg Co., which spread glue on its first panels with paint brushes and pressed them with house jacks in time for the 1905 World's Fair in Portland, Ore. The product began in the industrial sector, the APA says, used for products such as automobile running boards and door panels.

Softwood plywood took off in construction during the post–World War II housing boom. "It probably helped house a whole generation of people," says Dennis Hardman, vice president of marketing for the APA. "Throughout the rest of modern history, it's provided that for construction."

Plywood is often called the "original" engineered wood product, says the APA, and gave rise to some of today's most important building products, including OSB, I-joists, and LVL. Though today plywood has been overtaken by OSB in many construction areas, it continues to play an important role in the industry. Hardman predicts demand for plywood should remain steady for years to come.

The industry celebrated the milestone on March 18 in Portland, where more than 300 attendees took part in a banquet that included a keynote address by Chet Orloff, director emeritus of the Oregon Historical Society, a video chronicling plywood's history, and several awards recognizing people and companies for their contributions to the industry.

To view a detailed history, along with historical photographs, visit www.apawood.org. –K.T.