Specification

The Corrosion Problem
• CCA treated wood, used for almost 70 years,
is no longer available for residential usage
due to its negative environmental and health
eects.
• Environmentally safe but significantly more
corrosive preservatives (ACQ, CA-B, ACZA)
replaced CCA as of January 1, 2004.
• New wood treatments are approximately 2.5
– 4 times more corrosive to galvanized metal
components compared to the historically used
CCA.
• Corrosion may become visible in a short
period of time – weeks or months rather than
years. Wet conditions accelerate the corrosion
rate.
• Heavier galvanized coatings (G185 or batch
hot-dip galvanized) extend the life of the
connectors and fasteners, however the
corrosion mechanism and rate do not change.
The use of additional protection is highly
recommended.
Good news for the environment is bad news for decks.
New wood preservatives cause accelerated corrosion.
Wood Preservative Abbreviation Key
CCA Chromated Copper Arsenate
ACQ Alkaline Copper Quaternary
CA-B Copper Azole
ACZA Ammoniacal Copper Zinc Arsenate
Galvanized joist hanger attached to ACQ
wood, 7 months; wet conditions.
Self-Adhered Flashings