What materials are acceptable for use in ACQ lumber?
18-8 or 316 stainless steel would be perfectly fine without a coating in ACQ lumber. Your other choices would be an extremely durable barrier type coating on a carbon steel fastener. Any of the sacrificial coatings including zinc (electroplated or HDG) are designed to give themselves up to protect the base metal. Unfortunately the chemical reaction between the wood and the zinc means the zinc coated parts won’t last too long. There are many dip-spin coatings that are acceptable to use in ACQ treated lumber that can be applied to a carbon steel fastener if stainless steel is not a viable option.
