Thanks to its aesthetics and overall durability, wood has become a favorite home construction material through the years. Unsurprisingly, several products have been developed to care for it and extend its life, such as wood preservers.
Termites, fungi and wood-boring insects are timber’s three worst enemies. Fortunately, protection is possible through various types of natural and synthetic wood preservatives and treatments today.
Types of Wood Preservatives
Chromate Copper Arsenate
Chromate copper arsenate (CCA) is a pesticide that protects wood against termites, fungi and other pests that can erode it. It has been a popular wood-preserving pesticide since the 1940s. One concern raised by the United States’ Environment Protection Agency, however, is that arsenic may leak out over time and endanger the health of those who are exposed to it.
To mitigate the risks that come with wood treatment in general, all treated wood should be sold with a Consumer Information Sheet that details all handling and disposal precautions that must be taken. Several manufacturers though opt to provide Material Safety Data Sheets rather than CIS. While there is an ongoing debate about the practice of distributing information about treated wood, what’s important is that the consumer is aware.
Oil-Borne Wood Preservers
Two very common oil-borne preservatives today are creosote and pentachlorophenol. Creosote has been a common figure in the history of protecting outdoor wood structures like bridges and railroad ties. In this method, the timber is placed in a sealed chamber, and a vacuum sucks out the air and moisture out of the wood. Then the creosote is applied by way of pressure treatment. Acting like a pesticide and a disinfectant in one is pentachlorophenol, an organochlorine compound. The substance can be applied through pressure or brushed into the wood, or the wood may be soaked or dipped in it.
Water-Borne Wood Preservers
Water-based preservatives are typically the least expensive, but their disadvantage is that they tend to cause swelling or warping because of the water that they contain. Copper HDO and ammoniacal copper zinc arsenate are just two of the various types of water-based wood preservers available today.
A remarkable trend in the modern wood preservative industry is the production of more environment-friendly options like heat treatments and acetylation. When subjected to extremely high temperatures in the absence of oxygen, timber becomes inedible to insects and microorganisms due to the resuling alterations in its chemical makeup.
Acetylation does not involve pressurized treatments but instead protects wood by reducing moisture in the cell wall until nothing is left for fungi to thrive. The wood then becomes stronger and more termite-resistant because it is now harder and drier than before.