Wood Preservation and related topics

This information was compiled to address some of the frequently asked questions about treated wood. In this context we define treated wood as wood that has been pressure treated with a preservative to improve the resistance of the wood to destruction from fungi, insects, and marine borers.

Wood in contact with the ground, or wood used above ground that often gets wet, is attacked by decay fungi and insects. Two common examples of this type of application are decks and fence posts. With the exception of naturally durable species such as redwood and cedar, wood used in these applications should be pressure treated with preservatives if it is expected to last more than a few years. For several decades, consumers have been able to purchase pressure-treated wood at their local lumber yards. This type of treated wood, commonly called "green treated," was most likely pressure impregnated with a preservative called chromated copper arsenate (CCA). CCA is an extremely effective and durable treatment against both decay and insect damage. This relatively inexpensive preservative treatment has been used since the 1940s. Alternative preservative treatments are now available.