How is wood treated

Wood has always been considered an ideal building material. And, the need to ensure that the wood lasted has been a consideration just as long. Hundreds or even thousands of years ago, people used oils, soaking or painting the wood with olive oil or tar. In more recent history, the need for long-lasting wood increased with the expansion of the railroad system in North America. Then, with the advent of electricity and the need for a safe way to carry it from power plants to homes, utility poles became as necessary as railroad ties.

And onward pushed the innovation into more advanced preservative products and the methods used to impregnate wood with preservatives designed to lengthen the life of wood. In 1833, John Bethell, in a process that has come to be known as “full cell”, learned that improved treatment could be achieved by placing the wood in a vacuum prior to applying chemical. The vacuum removes air from the interior regions of the wood structure and allows it to accept the treatment more readily. Later it was discovered that application of heat could remove moisture from the wood, a step that is helpful for oilborne preservative treatments. In addition to oilborne preservatives, waterborne preservatives were developed nearly a century ago and also are treated with forced impregnation of the wood during a closed process in a cylinder.

In the meantime, the American Wood Protection Association (AWPA) was founded just after the turn of the 20th Century to document and standardize best practices. Individual members of the wood industry come together as the principal Standards-writing body for methods, preservatives, and other technologies which protect wood and wood-based products. Other organizations, even within the US department of agriculture, were founded to contribute to the healthy use of forests and wood products. Wood preserving technology continued to advance.

Today, the wood industry continues to research and innovate, always looking for better, more efficient ways to protect wood.