Green lumber – also called wet lumber – is construction wood that contains more than 19% moisture. Wood that has less moisture than that has been kiln-dried or otherwise seasoned and is more commonly used in high-quality construction. Green lumber is typically used as an effort to cut down on construction costs. All wood eventually dries itself out until it reaches a similar level of moisture in the air around it. When this happens, the wood will shrink, which can cause nail popping, warping, gaps, or discoloration from sap, among other issues.
Why should you care about any of this? Well, if you’re building a new home and your contractor suggests using green lumber to cut costs, you should be forearmed with knowledge before making a decision. If you bought a relatively new home and are seeing some of the issues mentioned above, it could be that the reason for them is that the contractor used green lumber when building the home.