What is the purpose of the lead in lead-coated copper?
Lead-coated copper is the copper industry’s response for a strong, lightweight, durable, easy-to-install gray metal finish on a copper substrate. The material has been available since the early 1900s. Lead-coated copper does not extend the life of a copper roof. Its purpose is to provide an alternative color to architectural copper applications. In addition, lead-coated copper runoff fulfills the objective of providing a metal whose runoff staining is compatible with light-colored materials such as masonry, marble limestone, stucco and light painted woodwork. The stains produced range from light to dark gray in color and resemble the natural atmospheric weathering of masonry or paint. In instances where the lead coating is porous, under exterior conditions, incomplete or pitted, rapid pitting corrosion of the underlying copper can occur due to galvanic action.
