Borax Wood Rot Repair

Updated April 17, 2017

Borates, like borax and boric acid, are desiccants, meaning they dehydrate and kill the organisms causing both wet and dry rot in all types of wood. Since borates are water-soluble, they penetrate to repair and protect wood from insects, fungi and water damage. While name brands such as Tim-borĀ® and Bora-CareĀ® provide guaranteed, lasting protection, you can easily make inexpensive borax for wood rot repair at home using common chemicals and water.


Remove as much of the rot as possible. Before you begin treatment, or even mix your solution, clean out any areas of decay you can find with a screwdriver. Remove any wood that is soft to the touch or has visible holes or infestations. Clear the area of debris and infested wood. You can also drill small holes into the wood to help inject the solution more deeply.

Warm the wood prior to applying the mixture. Choose a time of day after the wood has been exposed to the sun, or warm the wood with a heat gun or hair dryer. Warming the wood opens up the pores and helps seal the solution into the wood as it cools.

Prepare the Solution

Decide on the amount and concentration you will need for your project. Each gallon of solution is sufficient to treat 200 square feet of wood. Concentrations of 10 per cent must be applied twice, while 15 per cent concentrations usually only need one application.

Make a gallon of solution by adding 0.454kg. of powdered boric acid to 3 qt. of warm water in your bucket for a 10 per cent concentration. Add 0.68kg. of borax to about 3 qt. of warm water for a 15 per cent concentration. Agitate or stir the mixture until the powder completely dissolves. To make more solution, simply double the proportions.

Apply the Solution

Apply the solution within 24 hours of mixing. Otherwise, the active ingredients may cease to be effective. Saturate the affected wood as well as any surrounding wood to prevent the spread of rot and fungus. Use a paintbrush for smaller areas or a high-pressure sprayer for larger jobs. Apply one coat of 15 per cent mixture or two coats of 10 per cent solution. Wait at least four hours before applying the second coat. Allow the sections to dry completely before moving on to epoxy treatment.

Seal the wood with several layers of paint or sealing product to trap the borax treatment in the wood and prevent future decomposition.

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About the Author

Page Turner was destined to be a writer, publishing for the first time at the age of 14. Since that time, she has worked as an writer and editor for publications and websites including The Ray and The Howler. She has published her first children's book and founded a multi-lingual literary magazine while working as a communication studies scholar at the College of Charleston.