
Proper seasoning and storage provide optimal dimensional stability of lumber in service. To minimize shrinkage, SPIB Grading Rules require dimension lumber 2" or less in thickness be kiln-dried or seasoned to a moisture content not exceeding 19%. This will result in an average moisture content of about 15% at the time of manufacture. Additional conditioning will take place when lumber is stored and used as it adjusts to the moisture content of its end-use environment. For interior items, such as flooring, millwork and furniture, the end-use moisture content will average between 6% in the dry
Southwestern U.S. and 11% in the humid U.S. Gulf South. For exterior items, such as framing, siding and sheathing, the end-use moisture content will average 12% in most areas of the U.S., with a range from 7% to 14%.
Proper receiving, unloading, storage, handling, installation and bracing of lumber after delivery will help maintain material quality during construction and service life. Follow these simple rules to help ensure proper storage and product performance at the job site:
There is additional protection when lumber comes in paper-wrapped packages or has been treated with a weather protective coating. However, availability is limited and weather-protective coatings are generally effective for only about three to six months. Damage to the paper during transportation can reduce its effectiveness, and protection is lost when paper wrappings are removed. For additional information, refer to the SPC publication Managing Moisture and Mold.


Proper seasoning and storage provide optimal dimensional stability of lumber in service. To minimize shrinkage, SPIB Grading Rules require dimension lumber 2" or less in thickness be kiln-dried or seasoned to a moisture content not exceeding 19%. This will result in an average moisture content of about 15% at the time of manufacture. Additional conditioning will take place when lumber is stored and used as it adjusts to the moisture content of its end-use environment. For interior items, such as flooring, millwork and furniture, the end-use moisture content will average between 6% in the dry
Southwestern U.S. and 11% in the humid U.S. Gulf South. For exterior items, such as framing, siding and sheathing, the end-use moisture content will average 12% in most areas of the U.S., with a range from 7% to 14%.
Proper receiving, unloading, storage, handling, installation and bracing of lumber after delivery will help maintain material quality during construction and service life. Follow these simple rules to help ensure proper storage and product performance at the job site:
There is additional protection when lumber comes in paper-wrapped packages or has been treated with a weather protective coating. However, availability is limited and weather-protective coatings are generally effective for only about three to six months. Damage to the paper during transportation can reduce its effectiveness, and protection is lost when paper wrappings are removed. For additional information, refer to the SPC publication Managing Moisture and Mold.