Can I install aluminum materials directly on ACQ pressure-treated lumber?
No. New pressure-treated lumber with “Alkaline Copper Quaternary” (ACQ) replaces the old “arsenic-laced” (ACC) pressure-treated lumber which was abandoned voluntarily by the Canadian manufacturers following an agreement concluded with Health Canada. Some manufacturers offer a product showing the same qualities and the same longevity as the old treated lumber. The disadvantage of this new treated lumber relates to the corrosion of materials in direct contact. When two metals are in direct contact in a moist environment, the less noble one will corrode. It acts as the anode as the second, partly protected from corrosion, will be the cathode. This phenomenon is called galvanic corrosion or galvanic cell effect. The further apart the metals on the galvanic scale, the higher the speed and importance of corrosion will be. Since copper and aluminium are very distant on the scale, galvanic corrosion is at high risk. Indeed, the presence of copper in great quantity accelerates the corrosion of
