Wet lumber, also referred to as green lumber is wood used for construction that contains a higher level of moisture that that of kiln dried wood.
Freshly cut trees tend to hold a lot of water in their cells. Water that has collected in these cells is referred to by the term ‘free water’. After the tree has been cut, this ‘free water’ begins to slowly evaporate. It only stops doing this when the level of moisture in the wood reaches the same level of moisture as the environment it’s in. The term for this process is EMC (equilibrium moisture content).
When it comes to wet lumber, it has not had enough time to reach EMC before it is used in construction. The evaporation process is generally prevented because it is usually wrapped in plastic before being stored after processing. When the wood is unwrapped, just before being used for a job, the wood still contains a high level of moisture.
There are some areas where wet lumber will often be used. These are drier and hotter areas. For example, areas in the United States like Arizona and parts of California will use wet lumber due to the fact that the wood will dry out much faster.
Maybe you’re wondering “why use this type of lumber in construction then?” The fact is that wet lumber is usually a cheaper option. Also, due to it being a softer wood, it is less prone to splitting and easier to drive a nail into. There are problems that can also arise from the use of wet lumber. Please feel free to contact us for more information.
Dave Graham, Tempest Home Inspection. Calgary Alberta