How to Use Borax to Preserve Wood

Quck answer

Wood can be treated with borax to protect it from pests and fungi. Borax is a natural mineral that acts as a preservative and insecticide. To treat wood with borax, dissolve it in water and apply it to the wood surface. Borax penetrates deep into the wood fibers, killing any existing pests and preventing new infestations. It also inhibits the growth of fungi and mold. Borax-treated wood can be used for various purposes, such as building structures, furniture, and outdoor decking. Regular maintenance and reapplication of borax may be necessary to ensure long-lasting protection.


When it comes to outdoor construction, most of us are familiar with pressure treated lumber. This process involves infusing a compound into the wood fibers to slow down decay and extend the lifespan of our decks. However, another, less well-known method of preserving wood is by treating it with Borax. This can help to reduce water content, prevent fire, and deter wood-eating insects. Borax is a water-soluble mineral that can be used to treat various products, including those used in the building industry.

Step 1

Before you begin, create a protective barrier around the wood that you intend to treat. The Borax solution may seep into the ground and can be harmful to certain types of grass. To prevent any overdosing of Borax on plants and animals, it is important to prepare a suitable work area by using an edge guard or towels to catch any solution that may run off.

Step 2

Arrange the raw wood in such a way that each side can be treated with the Borax solution. Make sure that you are able to flip the pieces to evenly cover all surfaces with Borax. Take the pump sprayer and the Borax to a water source and mix up a batch of Borax wood treatment.

Step 3

Dissolve 10 oz. of Borax (specifically the 20 Mule Team variety) in approximately 6 oz. of warm water. Stir the solution until the Borax is fully dissolved. Pour this mixture into 1 gallon of plain tap water and mix well. Transfer the treated gallon of water into the hand pump sprayer and securely tighten the cap. Pump the sprayer to pressurize the contents.

Step 4

Evenly spray the solution onto each side of the raw wood boards. By treating the wood with a simple Borax and water solution, the presence of Borax within the wood helps to repel pests, inhibit fire, and speed up the curing process. Begin by spraying one side, then flip the board on its edge to spray the side, then flip it again to spray the back, and finally, spray the other side. Repeat this process for each board until the solution is fully used. One gallon of solution is enough to treat around fifty 2x4x8 studs.

Step 5

Allow the wood to cure as you would normally. Depending on your location, you can either kiln dry or air dry the wood until it reaches the desired moisture content. Determine the appropriate moisture level for your area and ensure that the wood has the recommended amount of moisture in its fibers. Once cured, install the wood as you would with any other type of treated wood.

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