Imperfect, Perfect Lumber: Large Timbers Will Have Cracks, Part 2

Douglas Fir timbers

Douglas Fir timbers

Perhaps you’re not quite sold on the idea that cracks and checks actually enhance the natural beauty of large timbers: You’d much prefer to avoid those unsightly characteristics altogether. Well, you can do it, if you want to. But once you understand how, we think you’ll change your mind. Maybe you can even find beauty in them, after all.

Historically, one means has been used to avoid what some consider unsightly checks and cracks while providing for the same release of pressure. Dating back to circa 600 BC with Japanese Temple Carpenters, people have been cutting saw kerfs into timbers to provide a release point and lessen the chances of checking. Because unlike natural checking, the position of saw kerfs can be determined by the builder, which means that they can be positioned in areas that won’t be as easily seen.

Douglas Fir timber joint

Douglas Fir timber joint

The kerfing approach has a down side, though: It must be cut before the timber begins the drying process. Since lumber suppliers like J. Gibson McIlvain typically don’t have access to a timber until it’s already been kiln dried and air dried for some time, by the time your order is placed, the timing for kerfing has long been past.

Typically, timbers don’t begin to check until they’ve been installed on a deck or in a home where they receive direct sunlight. In fact, customers may report hearing popping and cracking noises from their recently installed posts. Owners of timber frame homes mention hearing cracking sounds for many years after their home has been built. Understandably, these customers may think they have defective wood.

As always, education can go a long way toward correcting misperceptions. When customers are informed by the builders and have reasonable expectations, they’re much less likely to have unrealistic expectations and the frustration and disappointment that result.

Full kiln for drying lumber

Full kiln for drying lumber

A new method of drying can actually make it possible to reduce checks and cracks, without compromising stability. Lumber drying often involves both air drying and kiln drying. The North American standard for kiln-dried lumber is 6-8% moisture levels. However, kiln-drying large timbers can be dangerous, because case hardening can easily result, with a hard shell trapping moisture inside. While the lumber may appear to be flawless, it’s actually quite unstable. If the lumber is cut again, it will move dramatically. One alternative to traditional kiln-drying is utilizing a Radio Frequency vacuum kiln. This drying method is only currently available for a select few species and sizes.

Because wood never stops moving, the cracks will continue to open and close with shifts in moisture levels; because of that fact, checks should not be filled in. Instead, you should consider each of them to be character marks, displaying the unique natural beauty and ingenuity of lumber. As seasons change and lumber weathers changing seasons and even completely new environments, it reminds us of our inner strength. We may desire to be flawless, when it’s actually our cracks that add to our own resilience, revealing a deeper beauty than we could have had before.

Read the Entire Series

J Gibson McIlvain lumberyard

J Gibson McIlvain lumberyard

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.

Share Your Thoughts

*