Since all types of preservative treated wood are potentially more corrosive to fasteners than untreated wood, the treated wood industry and manufacturers of CA, ACQ and ACZA all strongly recommend true hot-dipped galvanized or stainless steel fasteners over other types of "galvanizing" (i.e. hot-galv. electro-galv, e.g.)with their treated wood products. In fact, use of these prescribed fasteners is more important than ever since the new preservatives are more corrosive than CCA treated wood.|
The transition to the new Arsenic and Chromium-free lumber treatments such as ACQ, Copper Azole, etc., has presented a major challenge to the fastener and hardware industry. These new treatments are proving to be significantly more corrosive than the old CCA treatment. The major treatment chemical manufacturers continue to recommend hot-dip galvanized and stainless steel fasteners for the application of their products. They also state that hot-dip galvanized fasteners must conform to the ASTM Standard A-153. Please beware of some fastener manufacturers’ claims that are cleverly worded to suggest that they fully comply with the requirements of ASTM A153, Class D coatings. They may have some other type of coating that complies only with the “coating thickness” requirements of A153 or claim their fasteners are superior to hot-dip galvanizing in regard to Salt Spray Testing (which seldom has any relevance to real world conditions). They may also claim to have “approval” for use in ACQ, Copper Azole or other new treatment, but no such approval agency or industry accepted testing protocol currently exists.
The very first line of the ASTM A153 specification states “This specification covers zinc coatings applied by the hot-dip process on iron and steel hardware.” At Maze Nails, we have been using the true hot-dip galvanizing process on our fasteners since 1914. In 1955, we introduced our exclusive STORMGUARD process of Double Hot-Dip galvanizing which consistently provides a smooth, uniform coating that does not fill in the threads of ring or spiral shank nails. True hot-dip galvanized coatings provide a zinc-steel alloy layer between the steel core of the nail and the outer layers of zinc that are actually harder than the base steel itself. So don’t gamble with recently developed, unproven coating technologies that seem to good to be true. The current International Building Code and International Residential Code include both stainless steel and Hot-Dip Galvanized fasteners in their recommendations for pressure-preservative treated wood -- and Maze Nails provides a wide variety of fastener choices in both types.