Hopefully Part 1 helped you understand a little more about why it’s not quite enough to request kiln-dried lumber as well as how we ascertain the moisture content of imported lumber. Now it’s time to learn about the rest of our re-drying process.
Re-Drying Without Compromising Quality
Two major factors in determining the duration of time a pack of lumber spends in our air-drying yard are species and moisture content. If we rushed lumber to the kiln without allowing the appropriate amount of time, we’d cause problems that would become evident later on. Stability can become an issue when lumber is improperly dried. Because kiln-drying produces a hardening of the cell walls within the wood, it can produce increased stability. As the lumber is dried the additional amount to get it from the European standard of 10-12% to the American standard of 6-8% moisture content, it becomes especially stable. (The 8% level is a major benchmark in stability.)
Of course, once lumber comes out of the kilns, it begins to absorb atmospheric moisture; however, kiln-drying to 6-8% is still important, because of the hardening of the cell walls. That hardening does not get reversed, so even when the wood does absorb moisture, it does so at a slower pace and also sheds that moisture more quickly. The practical result means less dramatic movement, such as bowing, twisting, cracking, or warping. Even when a major rain storm comes in or humidity levels are through the roof, your trim, walls, flooring, etc., won’t be at risk.
Why It Matters To Builders
If you feel like the details of how lumber is dried are interesting but insignificant, think again. Any builder wants to make sure he’s using quality materials and paying a reasonable price for what he’s getting. When you buy lumber that’s re-dried to North American standards, you’re buying quality material that won’t crack or warp as it moves from the lumber yard to your job site, or as time goes by and seasons change.
Since the extra drying costs extra time and money, it will cost more. However, both re-dried lumber and lumber merely dried to European standards can be referred to as “kiln-dried lumber.” When you see a significant price difference in African hardwoods, you can be pretty sure that the lower prices indicate lesser quality, possibly in the form of steps skipped in the quality process, without re-drying the lumber properly.
As a customer, you should feel free to ask your lumber supplier about their drying process, quality control, and other details of the product you’re purchasing. Here at J. Gibson McIlvain, we welcome such questions and truly delight in helping our customers grow in their knowledge of the lumber industry, our quality process, and the particular details about the products we carry.
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 when wood goes through the kiln, the cell walls of the wood is hardened significantly. Especially if you were trying to be safe and strong structures, you would want ever cell of the wood to be as hard as possible. Makes sense that so many would opt to use kiln dried lumber. Thank you for the read.