Why was ACQ treatment selected in place of CCA?
According to the U.S. Environmental Protection Agency, Washington, D.C., ACQ is a water-based wood preservative. It was chosen because of its ability to guard against decay and insects while being environmentally friendly. What problems can ACQ-treated lumber cause to metal roofing fasteners? The copper in ACQ has a tendency to accelerate the corrosion of zinc-plated fasteners. The zinc plating corrodes in the form of white rust (zinc oxide) until the bare carbon steel is exposed and corrodes in the form of red rust (iron oxide). One of the most common causes of rusting steel fasteners is galvanic corrosion, which takes place when all the following occurs: > Dissimilar metals are present. > An electrical contact path between the metals is present. > An electrolyte is present. All three conditions exist when metal-roofing fasteners are installed into ACQ lumber. What can be done to fasteners to show or eliminate corrosion? There are many ways to minimize fastener corrosion. One way is b
