Taking the time to consider how lumber is treated can give woodworkers a better insight into how to approach their next woodworking project. For example, some treated lumber adversely reacts to materials such as metal. But beyond that and the typical aspects of color, texture and durability, understanding treated lumber options can influence the longevity of projects and how to care for them.

Examples of treated lumber include:

Thermally-Modified Wood (TMW) This wood goes through a four-step process that uses extreme heat and steam to change the structure of the wood and remove those properties that make it most appealing to insects, fungi and mold. This process also makes the wood more weather-resistant and longer-lasting than its untreated counterparts. Over time the patina shifts to gray if left untreated.

Non-Metallic Stabilized Weather-Resistant Wood (NMSWR) The most notable feature of NMSWR is that it is a certified green product by the National Association of Home Builders. Unlike other pressure- or surface-treated woods NMSWR does not contain metallic wood preservatives and has a wood stabilizer that enhances its durability to the core. It weathers into a natural brown color, and eventually turns gray from long-term exposure to the sun if left untreated.

Although many have come to think of treated lumber as chemically-charged, harmful to the environment and lasting only slightly longer than the original product, it is also important to recognize the wood’s environmental potential. In recent years new bio-based technologies now offer more sustainable methods that not only can meet a woodworker’s needs but improve overall quality of projects as well.