Frequently Asked Questions about Wood Preservation
(and related topics)

More Information

Click for more information on the topics below: Topical Publication Lists   o Acid copper chromate (ACC)   o Alkaline copper quat (ACQ)   o Ammoniacal copper citrate (CC)   o Copper azole (CBA-A or CA-B)   o Copper dimethyldithiocarbamate (CDDC)   o Environmental impacts of treated wood and methods to reduce the impacts   o Disposal and reuse of treated wood   o Natural durability   o Control of moisture in buildings   o Experimental preservative treatments   o Research methodologies in the field of wood preservation   o Effect of preservative treatment on mechanical properties   o Wood products production and consumption   o Field treatment Links to other sources   o American Wood-Preservers' Association (http://www.awpa.com/)   o Forintek Canada Corp./ Canadian Wood Council (http://www.durable- wood.com   o Southern Pine Council (http://www.southern pine.com/)   o Western Wood Preservers Institute (http://www.wwp institute.org/)   o U.S. Environmental Protection Agency (http://www.epa.gov/)   o US Forest Service, Forest Products Laboratory (http://www.fpl.fs.fed.us/)     FPL Publications   Recent FPL Publications are generally availabe from our Web site at http://www.fpl.fs.fed.us/ publications.html as PDF files. The most recent FPL publications are listed in "Dividends from Wood Research," FPL's semiannual listing of new publications. Sections of the listing relevant to wood preservation are "Durability" and "Decay Processes and Bioprocessing."   o Most recent issue   o Cumulative list (January 1996 to present) Two chapters of the Wood Handbook are particularly relevant:   o Wood Preservation, Chapter 14   o Biodeterioration of Wood, Chapter 13 Send comments to: Carol Clausen, Project Leader Wood Preservation US Forest Service, Forest Products Laboratory One Gifford Pinchot Drive Madison, WI 53726-2398 cclausen@fs.fed.us top of page

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.

Frequently Asked Questions

The first questions address new restrictions on the use of CCA-treated wood and the available alternatives. Then other frequently asked questions on wood preservation and related topics are also addressed. With few exceptions, references in this document were limited to publications of the Forest Products Laboratory. These answers are not intended to represent a complete review of the available literature.

1. What are CCA, ACA, ACZA, etc.?
2. Is it true that EPA has banned CCA-treated wood?
3. What are the alternative types of treated wood for residential use?
4. Has FPL evaluated these treated wood products?
5. Should I have concerns about existing CCA-treated wood?
6. How do I dispose of treated wood?
7. What about naturally durable species?
8. How can I extend the life of untreated wood?
9. Where can I find the climate index map of relative decay hazard?
10. What research is FPL doing on wood preservatives?
11. What experimental preservative treatments for wood has FPL investigated?
12. What test methods are used to evaluate new preservative treatments?
13. What is the impact of preservative treatments on mechanical properties of wood?
14. How can I tell if my wood is properly treated?
15. Where can I find additional information related to wood decks?
16. What is the market for treated wood?
17. Where can I find lumber treated for both flame retardancy and preservation?
18. Does FPL have any information on remedial or field treatment of wood?