Green lumber, also referred to as wet lumber, is wood that is used for construction, which contains a higher level of moisture.
As we would naturally expect from any living organism, a tree that is newly cut holds a lot of water. The term ‘free water’ is used for water that has collected in the cells of the wood. After a tree has been cut down, the free water gradually evaporates until it reaches a water content level that is equals to its environment. This is known as equilibrium moisture content, or EMC.
Obviously then, the more time the wood is left before being used for construction etc. the more time the wood has to dry out, which makes it better to use. This is not the case with green lumber though. It has not usually had enough time to dry. It is often covered in plastic wrapping and stored after processing. This affects the evaporation process, which means the wood will continue to have a high moisture content.
Areas of the country like Arizona and parts of California, which are hotter, often use this kind of wood for the simple reason that it will dry out quicker.
You might ask why this type of lumber is used in construction? As is often the case, it comes down to price. Green lumber is typically cheaper to use. It is softer, which makes it easier to use. It’s easier to cut and drive nails into without it splitting
Other questions could be raised when we think of whether green Lumber a good option. For example, is it better to use kiln dried wood? This is a topic we will consider in our next blog.