Q&A: ACQ-Treated Wood and Fastener Corrosion

A.Kevin Archer, product development manager at Chemical Specialties, a Charlotte, N.C., manufacturer of ACQ, responds: All types of preservative-treated wood are potentially more corrosive to galvanized fasteners than untreated wood. Under controlled tests for corrosion, galvanized-steel fasteners in ACQ-treated wood perform similarly to galvanized fasteners in wood treated with other preservatives (CCA, ACZA, and copper boron azole).

The treated-wood industry recommends the use of hot-dipped galvanized-steel fasteners, which have a thicker coating of zinc than electroplated galvanized fasteners. In environments where treated wood is expected to remain wet for long periods of time, stainless-steel fasteners will perform better than hot-dipped galvanized fasteners.