Wood has been a favorite material for home building projects through the years, owing to its beauty and general durability. It’s not surprising that various products have been created to preserve and care for it, such as wood preservers.
Timber has three mortal enemies, namely, fungi, wood-boring insects, and termites. Fortunately, protection is possible through various types of natural and synthetic wood preservatives and treatments today.
Types of Wood Preservatives
Chromate Copper Arsenate
Chromium copper arsenate is a pesticide that strengthens wood against fungi, termites and other pests. It has been used as a wood-preserving pesticide since way back 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 control risks linked to wood treatment in general, the American Wood Protection Association recommends that treated wood be sold with a Consumer Information Sheet, where instructions on safe handling and disposal are provided. Several manufacturers though opt to provide Material Safety Data Sheets rather than CIS. There is a never-ending debate on this practice of distributing information regarding treated wood, but the more important point is that the consumer is fully aware of the product.
Oil-Borne Wood Preservers
Two of the most popular types of oil-borne preservatives 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. Pentacholorphenol, an organochlorine compound, is both a pesticide and a disinfectant rolled into one. 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 Preservatives
Usually the cheapest wood preservatives in the market are those that are water-based, but because of their high water content, they have the tendency to make wood swell or warp. 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.
Instead of infusing water-based preservatives into wood through pressure, acetylation chemically changes wood by reducing moisture in its cell wall enough that fungal degradation becomes impossible. This makes the wood not just stronger but termite-resistant too, being harder and drier than its unmodified counterpart.