How do you fix bug-infested wood?
I recently noticed small mounds of wood dust surrounding surface holes in a pile of air-dried lumber, telltale signs that insects have staked their claim. What can I do to get rid of the bugs and salvage the wood?
—Scott Hartung, Kennewick, Wash.
You have three options to put the kibosh on those invaders, Scott. If you do nothing, the bugs will continue to bore holes and leave debris for years to come.
Option 1: Discard or burn the wood. That may seem like a waste, but after you consider the time/expense of the next two options, it might be your best choice. Just don't bring the wood into your home, where the bugs could spread to your trim, cabinets, and furniture!
Option 2: Kill the bugs with heat. Known as sterilization in the lumber trade, this involves stacking the boards in a hot kiln. Your local kiln operator may not welcome buggy wood into his kiln, so you may have to build a heated enclosure with fans for air movement.
To kill all of the bugs, the center of the wood must heat to at least 133°F for 30 minutes. To achieve that with 1"-thick boards, the kiln would have to hold at 150–160° for about an hour, but two hours would be safer. Wood thickness greatly affects heating time: a 6×6 beam would require at least five hours in such a kiln. How you stack the wood, air circulation, and species also affect sterilization time, so err on the wood being in the kiln longer than necessary.
Option 3: Apply a borate chemical treatment. You can dilute Bora-Care with water; Tim-bor, a granular product, dissolves in water. Keep in mind those chemicals will reinfuse the wood with moisture, meaning you'll have to dry it again. And, once you've done that, the chemically treated wood must be handled as a hazardous material: Don't work with it indoors, wear a good respirator when machining it, wash your hands after touching it, and dispose of sawdust and other debris properly. Don't burn the scraps or use the sawdust as bedding, mulch, or compost.
Of course, prevention is the best medicine. Buying wood that has been heat-sterilized in a kiln should preclude the possibility of bugs being present. If you mill and air-dry your own lumber, remember that bugs love damp wood. So avoid logs that have been sitting on moist ground for more than a few days, or any logs that show even the tiniest of bug holes. Stack the boards to dry immediately after they come off the sawmill.