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.
Timber has three mortal enemies, namely, fungi, wood-boring insects, and termites. Fortunately, there are various types of natural wood preservatives and synthetic wood treatments available 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. The United States’ Environment Protection Agency is concerned, however, that arsenic may leak out and cause health risks to 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. 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 Preservatives
Creosote and pentachlorophenol are two of the mos common types of oil-borne preservatives. Creosote has been a common figure in the history of protecting outdoor wood structures like bridges and railroad ties. This technique calls for timber being placed in a sealed chamber, where air and moisture is removed from it through a vacuum. Then the creosote is applied by way of pressure treatment. 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 Preservers
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. Two examples of water-based wood preservatives are alkaline copper quaternary compounds and copper.
A rising trend in the industry of wood preservation is the creation of alternative methods that are more environment-friendly, such as acetylation and heat treatments. The chemical composition of timber, when heated at peak temperatures in the absence of oxygen, makes it inedible to insects and microorganisms.
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. This makes the wood not just stronger but termite-resistant too, being harder and drier than its unmodified counterpart.