Tim-bor Fungicide, Insecticide & Wood Preservative

- A low toxicity wood treatment for insects and rot fungi -

Summary: Tim-bor is a natural insecticide/fungicide that is widely used as a wood preservative for protection against both insects and rot fungi. It is composed of nearly pure sodium borate, a crystalline salt form of boric acid. It is applied as a dry powder to wall voids or as a water solution to dry, unfinished wood surfaces.

Jack DeAngelis, PhD

OSU Entomologist (ret.)

Tim-bor is an insecticide/fungicide/wood preservative composed of 98% sodium borate (borax), a sodium salt of boric acid. Tim-bor itself is a white, fluffy powder that can be puffed in to wall voids for carpenter ant control, or dissolved in water and applied as a course spray* to surfaces. See the fact sheet and specimen label below for additional technical and product use information.

As an insecticide/fungicide Tim-bor is labeled for use against termites, wood destroying beetles, carpenter ants, and wood decay fungi. It is very effective against many of the most important wood destroying organisms and exhibits relatively low toxicity compared to other pesticides.

When used as a spray borate crystals are deposited on the wood when the water dries and may even penetrate a short distance into the surface. Borate acts as a stomach poison to any insect that comes into contact with this layer. Keep in mind that since borate is water soluble it must be used in dry situations or sealed over to make it waterproof. Often, waterproof stains or sealers are applied once the spray dries.

* Tim-bor dissolves completely in water to make a true solution.

The Tim-bor label and fact sheet

A specimen label (see below) contains all of the information for registering a pesticide product in the US but should only be used for general reference. The product label, the label (use instructions) attached to the container you are using has the final, often updated information.

The main ingredient in Tim-bor, borax, is mined as a crystal of nearly pure sodium borate. Borax itself has many commercial uses including water softening, flame retardant, glass additive, and as an insecticide/fungicide. See the Related Articles below for more information.

Using Tim-bor Insecticide/Fungicide/Wood Preservative

Tim-bor is sold as a water soluble powder in 1 lb bags and 25 lb pails. A 1 lb bag makes 1 gal of working solution. Two coats, applied with a pump sprayer or paint roller, are often needed, see label instructions. The dry powder can also be puffed into wall voids to treat for carpenter ants. Like other borate-based wood preservatives Tim-bor is generally not available in stores but is available at DoMyOwn.com.

Mission: To provide accurate, up-to-date and unbiased information for solving common insect and mite problems around your home, business and landscape using least-toxic methods.

Please see the Disclaimer statements as well.