Throughout the construction industry, most people know to request kiln-dried lumber. What some may not realize, though, is that there are differences among kiln-dried lumber, depending on its origin. The major factor is the moisture content, and it can make a big difference in the timeline and success of your next job.
Understanding Moisture Content Concerns
The accepted moisture content for kiln-dried lumber here in North America is 6-8%. However, in Europe’s wetter climate, the normal range is 12-15%. While that difference might not seem significant for an exterior application, it can be quite the game-changer for interior work or when working in a particularly arid climate. In some situations, the 4-7% difference in moisture content could translate into disastrous results.
While you may not think that how Europe dries their lumber matters to us in the U.S., it actually does. Why? Exotic lumber is typically dried to European standards, largely because they’re run by European companies. This issue is particularly common among African and European species such as African Mahogany, European Beech, French Oak, Sapele, Utile, and Wenge. Because we realize that these species are dried to only the European standard, here at J. Gibson McIlvain Lumber we re-dry those species further, so they reach North American standards. But the process isn’t as simple as some may think.
Accurately Measuring Moisture Content
Here at J. Gibson McIlvain, quality is pretty high on our priority list. One of the first quality control steps we take when a pack of lumber enters our lumber yard is to take moisture readings of several areas. We’re careful to measure boards that are part of the outer layer of the pack as well as those buried deep inside the pack. Once we’ve taken at least 3 readings from each location, we record the numbers on a check-in sheet and send them through our Vision Tally System. Through that system, we receive accurate board footage and can send the lumber to our air-drying yards, where the boards can begin to acclimate to our local East Coast environment.
In some situations, a moisture meter gives a range of numbers, so we do further testing in order to attain a more precise measurement. We cut a sample and take the weight of the sample, dry it in an oven, and weigh it again. After some careful calculations, we are able to confirm the exact amount of moisture content. Regardless of the numbers, though, all the lumber we receive spends some time air drying.
Once the lumber is freed from the shipping containers, we give it at least a few weeks where it’s allowed to air dry, stacked and stickered to allow for proper air flow. At that point, we can get a more accurate, consistent reading of the moisture content of the entire pack. Of course, during that waiting time, the lumber usually dries a bit, as well, since our climate is drier than both the shipping container and the lumber’s climate of origin.
To find out more about our quality re-drying process, continue reading Part 2.
J. Gibson McIlvain Company
Since 1798, when Hugh McIlvain established a lumber business near Philadelphia, the McIlvain family has been immersed in the premium import and domestic lumber industry. With its headquarters located just outside of Baltimore, the J. Gibson McIlvain Company (www.mcilvain.com) is one of the largest U.S. importers of exotic woods.
As an active supporter of sustainable lumber practices, the J. Gibson McIlvain Company has provided fine lumber for notable projects throughout the world, including the White House, Capitol building, Supreme Court, and the Smithsonian museums.
Contact a representative at J. Gibson McIlvain today by calling (800) 638-9100.
Rachel Lannister says
You wrote that the level of moisture in kiln-dried lumber often depends on the origin of the lumber. I had heard in the past that kiln-dried lumber was a great option when looking for lumber. I’ll have to remember this, and make sure that I ask about origin when buying lumber, so I can know exactly what the moisture content of the wood is like. Thanks for the read.