What Is Tim-bor?

Tim-bor is a brand of borate-based penetrating wood treatment that kills wood-boring insects and wood-destroying fungi.

Applying Product

Close-up of rotting wooden wallClose-up of rotting wooden wall
Produced by Tennessee-based Nisus Corporation, Tim-bor is a slow-acting stomach poison for termites, carpenter ants and other wood-boring insects, and a fast-acting contact poison for decay fungi. The active ingredient, Disodium Octaborate Tetrahydrate, is derived from boron-rich mineral deposits. This active ingredient works by preventing insects and fungi from absorbing nutrients, thereby starving them to death.

Tim-bor comes in powder form. The powder is dissolved in water and sprayed on wooden sill plates, joists and other interior wooden framing of buildings. It's applied as a 10 percent solution made by mixing 5 pounds of Tim-bor powder with five gallons of water. Spray, let dry, and spray a second coat. Apply each coat at a rate of 5 gallons per 1,000 square feet of wood surface. Tim-bor is colorless, odorless, and won’t corrode nails and other metal structural fasteners. Because Tim-bor can leach out of wet wood, it is limited to above-ground application in dry locations protected from the weather.

About the Author

Herb Kirchhoff has more than three decades of hands-on experience as an avid garden hobbyist and home handyman. Since retiring from the news business in 2008, Kirchhoff takes care of a 12-acre rural Michigan lakefront property and applies his experience to his vegetable and flower gardens and home repair and renovation projects.