Borate Wood Protection in High Humidity

:: Thursday, May 2, 2019 :: Posted By Frank Wawrzos

Researchers from Columbia University and the NASA Goddard Institute for Space Studies recently warned that globally, humidity is on the rise. Aside from the potential repercussions for human health, high humidity has a significant effect on wood-based construction. Wooden structures are vulnerable to fungi and algae. And certain destructive pests, such as the Formosan termite, are more active in humid regions.

The need for moisture-resistant cellulosic construction materials is a concern that reaches beyond the construction industry. Yes, architects, engineers, and builders must develop best practices that take the effects of humidity and related issues into consideration. But community leaders must also consider local municipal codes for construction to help support safe building practices. And property owners should ask questions about the types of materials being used in the construction of their homes and offices.

One of the best ways to combat moisture-related damage in humid regions is by using borate-treated timber.

Boron benefits: Fighting fungal growth

Borates are a proven and reliable protectant against fungal growth on wood products. As such, borates enable construction that uses more environmentally friendly and sustainable cellulosic materials, even in areas where wood wouldn’t otherwise be feasible. Borates are also a boon in areas where termite activity is a threat. In Hawaii, for example, termites can destroy a home within a year. Yet borate-treated wood can resist fungal and termite attacks for decades.

Lumber and sawn wood

Tim-bor® is a high-performance preservative that can be used on sawn wood. Because it provides a high concentration of boron, it’s an excellent choice for application on timber that will used for rafters, cladding, and even exterior joinery. (If used in exterior applications, Tim-bor-treated products should be sealed with a water-repellent coating.)

In these uses, borates can help to protect structures from the damage caused by wood decay fungi, termites, and wood boring beetles. Specifically, Tim-bor can be used on difficult-to-treat hardwoods and contains no heavy-metal components or organic solvents. Plus, it has little or no effect on ferrous metals, plastics, rubber, putties, bituminous solutions, other sealants, or primer paints.

Oriented strand board and wood plastic composite

Zinc borates, such as those found in Borogard® ZB, help to protect oriented strand board (OSB) and wood-plastic composites (WPCs) by reducing fungal growth in interior applications. Some products that use Borogard ZB as a component carry as much as a 50-year warranty. And composite products treated with Borogard ZB resist every type of decay fungi they’ve been tested against, including copper-tolerant fungi. These types of products are effective for indoor treatment, especially around sill plates. Plus, OSB treated with Borogard ZB is less expensive than pressure-treated plywood alternatives.

Railroad crossties

Outside of home and building construction, borates are used in combination with creosote to protect railroad ties. The borates provide protection against fungi and insects, and the creosote helps to prevent the borates from leaching out of the wood (as well as providing additional antifungal protection).

Our commitment to the environment—and you

U.S. Borax has a history of research and innovation involving borate chemistries. Our advanced technical group in Boron, California, dedicates decades of experience—plus outstanding analytical equipment—to develop exceptional products for a growing list of customer applications. Plus, we partner with a cadre of institutional, academic, and industrial partners to advance the use and usefulness of borates in wood protection.

Our products help to provide this protection and can be planned for use from project initiation through completion. Plus, 20 Mule Team® Borax products can be used to help protect cellulosic construction and housing materials during repair, remodel, and facility maintenance. As a result, more communities than ever can utilize more affordable and eco-friendly construction—and trust it to last.



U.S. Borax, part of Rio Tinto, is a global leader in the supply and science of borates—naturally-occurring minerals containing boron and other elements. We are 1,000 people serving 650 customers with more than 1,800 delivery locations globally. We supply around 30% of the world’s need for refined borates from our world-class mine in Boron, California, about 100 miles northeast of Los Angeles.  Learn more about Rio Tinto.

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