Protecting Environmentally Sustainable Building Materials with Borates

:: Thursday, August 1, 2019 :: Posted By Frank Wawrzos
There are more than 60,000 species of tree—each with unique qualities. Balsa is renowned for lightness while black ironwood is so heavy it sinks. Wood has been used by carpenters, joiners, and builders over the centuries because it is versatile, easily workable, and beautiful.
But there are downsides. Wood's very popularity raises questions about logging and the sustainability of old-growth forests. Because it is a natural material, wood is also prone to attack from fungi and pests. This is the story of old technologies, new technologies—and of how U.S. Borax Borogard® ZB wood preservative makes a valuable contribution to the sustainability of our forest resources.

Engineered woods: Environmentally sustainable building materials

Improving on wood is not new. Engineered wood products have been around since ancient Egyptians used simple veneers to beautify tomb furniture. More recently, wood manufacturers have bonded wood chips together to create oriented strand board (OSB). With OSB, planks and sheets can be created with dimensions far larger than a sawn tree, and with better properties than the parent material. It is mechanically excellent, strong, consistent, easy to install and work, and is a popular material in housing construction for exterior siding, sheathing, flooring, and roofing.
In our environmentally conscious world, wood for construction has many benefits, including:
  • The only renewable building material
  • The most energy-efficient material we use: Although wood represents almost half of all industrial raw materials used in the United States, it consumes just 4% of the total energy needed to produce these materials
And, sustainability? The debate about renewable forestry hinges not only on the old-versus-new-growth ratio, but also carefully consideration of which species to harvest. Highly-desirable hardwood timbers, such as oak and ash, grow relatively slowly, and only a quarter of the volume of felled trees in these species can be used to provide solid sawn lumber.
Yet fast-growing but hitherto under-utilized “weed” trees such as the Great Lakes aspen can be manufactured into engineered wood, a sustainable material option. Although sawn aspen lumber is of no use in construction, we can use the wood fiber itself. Down to the smallest stems, it can be chipped and wafered mechanically. The trees regenerate from their roots, meaning they don't have to be replanted.
The chips, inches long by fractions thick, are flash dried, mixed with adhesives and hot-pressed into sheets, boards and strips. The result? An engineered wood product that delivers:
  • High and consistent quality, dimension, and manufacturing tolerance
  • Less thermal and humidity movement (swelling or shrinkage)
  • Surfaces that can be textured, coated and pre-primed for paint finishes
  • No knotholes
  • The strength of plywood or particleboard 

Borogard ZB protects engineered wood: Antifungal, antipest

For all its versatility, availability, and environmental virtues, aspen falls prey to fungal infestation more than most woods. Untreated OSB components can succumb rapidly and badly to rot. The bonded wood chips absorb water and, when wet, the panels can become an ideal home to fungal colonies.
In order to exploit the aspen's sustainability, manufacturers needed a fungal deterrent that kept its potency over many years. Additionally, the antifungal needs to be:
  • Environmentally-friendly
  • Economical
  • Non-volatile
  • Compatible with the manufacturing process
Enter borates and their well-known biostatic properties.
During OSB manufacture, Borogard ZB's slow-release zinc borate is sprinkled into the shavings and adhesive mix before the hot-pressing stage. About 40 grams per square meter are used, but this relatively small amount provides fungal protection in all climatic conditions.
If the wood stays dry, Borogard ZB's tiny crystals stay dormant. But if OSB gets damp, the zinc borate dissolves into action against fungus. It is actually mobile in damp wood. With borate-treated OSB, there is fungus-free peace of mind for the home owner.

How borates stop the rot

Borates have long been known to be effective wood preservatives capable of controlling both fungal and insect pests in timber, and their efficacy has been established through research carried out by scientists around the world.
Borates are not directly lethal to an organism but rather are considered to be biostatic, and control degradation by inhibiting necessary oxidative metabolic activity at the cellular level—a constant energy-producing process necessary for life. Because the way it works is fundamental, borates are effective against a broad spectrum of pests, with no known development of resistance.

Wood Resources

Boron is also an essential micronutrient for tree growth. Learn more about how U.S. Borax products help sustainability at the source:

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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