In our first article in this series, we explained the different standards for moisture content of kiln dried wood in North America vs. Europe. North American kiln dried lumber is considered acceptable when it’s dried to a moisture content level of 6-8%. The standard European level is 12-15%. Though this factor may seem insignificant, it can actually make a major difference in the lumber’s performance in the long term. We also discussed how crucial it is to find out if your imported lumber was kiln dried in a mill that goes by the European or North American standards.
In this article, we’ll take a look at the step-by-step process some North American lumber yards go through to get their imported lumber dried to meet North American moisture content standards.
Moisture Content Must be Measured Carefully
Determining the moisture content of a pack of lumber isn’t always easy. The outer layer of exotic lumber boards may yield a different reading than the inner layer. This is because the inner layer isn’t exposed to the surrounding air during the long trip from its nation of origin across the ocean and all the way to the lumber yard.
The Pack will be Inspected or Scanned to Find Total Board Footage
At least three different readings ought to be taken from different locations throughout the pack in order to come up with an accurate general moisture content level. After this first step, the lumber can go through a meticulous manual inspection that takes up a significant amount of time, or, if a lumber yard has the technology in place, it can be quickly scanned using a Vision Tally System. This system uses specially equipped cameras and laser technology to quickly determine the exact length, width, and thickness of the boards as well as an accurate overall board count.
The Lumber is Air Dried
After the pack of lumber is measured to find its moisture content and the boards are measured and tallied, it will be air dried in the lumber yard. There, it will have an opportunity to adjust to the local environmental conditions and become properly acclimated to its new surroundings.
Troubleshooting is Sometimes Necessary
If there’s a wide disparity between the moisture content of different boards within the same pack of lumber, an extra step may need to be taken to make sure it reaches the right drying level. A sample is taken, measured, and then oven dried to a zero moisture level point. After that, it will once again be weighed. Once the lumber moisture level is confirmed, air drying for that pack of lumber can finally begin and should last as long as it takes to get the lumber to the right moisture level.
Each step of this methodical process is extremely important when it comes to making sure customers get the best quality lumber possible for their interior or exterior applications. In our next article, we’ll take a look at some of the benefits of drying wood to North American moisture content standards.
