Wood as been a favorite home construction material over the years, thanks to its beauty and overall durability. It’s not surprising that various products have been created to preserve and care for it, such as wood preservers.
There are three major threats to timber – termites, fungi and wood-boring insects. 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 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.
As a way to control risks associated with wood treatment in general, the American Wood Protection Association recommends that all treated wood come with a Consumer Information Sheet that provides guidelines on safe handling and disposal. However, a lot of manufacturers choose to provide Material Safety Data Sheets instead. There seem to be endless arguments on this practice of disseminating information, but the most important thing is that the consumer is aware.
Oil-Borne Wood Preservers
Two of the most popular types of oil-borne preservatives are creosote and pentachlorophenol. Creosote has been widely used in history as a treatment for railroad ties, bridgework and other outdoor applications. This method involves putting timber in a sealed chamber and removing air and moisture using a vacuum. The creosote is then applied through a pressurized method. Pentachlorophenol is an organochlorine compound that works as a pesticide and as a disinfectant at the same time. 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
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. Two examples of water-based wood preservatives are alkaline copper quaternary compounds and copper.
A remarkable trend in the modern wood preservative industry is the production of more environment-friendly options like heat treatments and acetylation. Heating timber to extreme temperatures without oxygen changes its chemical composition and renders it useless to microbes and insects.
Rather than being applied to wood by way of pressure, acetylation chemically changes wood by sucking the moisture out of the cell wall until there isn’t enough for fungi to grow and proliferate, leading to wood degradation. The wood then becomes stronger and more termite-resistant because it is now harder and drier than before.