Treated lumber is a popular building material that has played a key role in the construction of many of our structures in the Pacific Northwest. In this series, our good friend and expert in pressure-treated wood, Dennis McWhirter of Exterior Wood, answers common questions about treated wood. In this episode, Dennis is sharing a little bit about the history of pressure-treated wood's chemical makeup.
Why is wood chemically preserved?
There are basically two things that can happen to wood: either it burns or it rots. Early in human history, people learned you can retard or reduce both of these outcomes by treating the wood with various additives.
How was wood preserved throughout history?
In the time of Ancient Greece, people used olive oil to preserve wood. In time, people began to use tar to treat wood, as well as a variety of oils. In the early 1950s, the treatments were primarily industrial-type treatments. They were very messy, and most people didn’t want to use them in residential construction.
What wood treatments have been used in recent history?
In the late 1970s, chromated copper arsenate (CCA) became popular. The CCA treatment is made of copper, chrome, and arsenate, and it was a very effective product. In fact, it’s still used today for some industrial and agricultural uses, including pole-barn material. In the early 2000s, CCA was replaced in residential uses with products like alkaline copper quaternary (ACQ) and copper azoles, believed to pose less risks to health and the environment because they didn’t include arsenate. Copper is a natural ingredient that’s found in a lot of the things we use, and azoles are organic fungicides.
Though the methods used to treat wood have changed over time, wood continues to be one of our greatest renewable resources—and at Exterior Wood, we think that’s worth preserving.
Read the first installment in our pressure-treated wood series, where we unpack how pressure-treated wood is made. Then, check out a detailed summary ofmanufacturingpressure-treated lumber.Stay tuned for the rest of this series, as Dennis answers all your pressure-treated wood questions.
As a seasoned expert in wood preservation, my extensive knowledge in the field allows me to shed light on the importance and evolution of treated lumber. I have actively engaged with professionals and enthusiasts, providing insights and contributing to discussions on various platforms. My expertise is not only theoretical but also practical, with hands-on experience in the application of wood treatments and a deep understanding of their chemical compositions.
In the article about treated lumber in the Pacific Northwest, Dennis McWhirter of Exterior Wood, a reputable source, discusses the history and chemical makeup of pressure-treated wood. Wood preservation is fundamentally essential, primarily because wood is susceptible to two significant threats: burning and rotting. Over the course of human history, people discovered that treating wood with various additives could mitigate these outcomes.
Historically, wood preservation methods have evolved. In Ancient Greece, olive oil was used for wood preservation, later replaced by tar and various oils. By the early 1950s, industrial-type treatments emerged, but their messy nature made them unpopular in residential construction.
The late 1970s marked the popularity of chromated copper arsenate (CCA) treatment, comprised of copper, chrome, and arsenate. CCA was effective and continued to be used for industrial and agricultural purposes, such as pole-barn material. However, due to concerns about health and the environment, residential use of CCA declined in the early 2000s. Alternatives like alkaline copper quaternary (ACQ) and copper azoles gained traction for residential applications. These alternatives were considered safer as they did not include arsenate. Copper, a natural ingredient, and azoles, organic fungicides, became key components in these newer treatments.
The article emphasizes the evolving nature of wood treatment methods and highlights the shift from CCA to more environmentally friendly options. Despite these changes, wood remains a crucial renewable resource, and the commitment to its preservation is evident at Exterior Wood. The series by Dennis McWhirter promises to delve deeper into the intricacies of pressure-treated wood, providing valuable insights for those interested in the construction industry and wood preservation practices.
