What additional treatment should sheet lead be coated with?

Sheet lead should be coated with asphalt paint as a protective measure. This is primarily because asphalt paint serves as a weather-resistant barrier, helping to prevent corrosion and deterioration of the lead material over time. Lead is susceptible to oxidation when exposed to moisture and air, which can compromise its integrity and effectiveness as a plumbing material.

Using asphalt paint not only enhances the durability of the lead but also minimizes the environmental hazards associated with lead exposure by encapsulating the material. Additionally, asphalt paint has good adhesion properties and is specially formulated to resist harsh environmental conditions, making it an ideal choice for protecting lead in plumbing installations.

In contrast, other coatings such as epoxy or polyurethane might not provide the same level of compatibility with lead materials and could potentially lead to chemical reactions that degrade the lead or the coating itself. Galvanized coatings involve a different process intended for steel and iron rather than lead, making them unsuitable for this application. Thus, the use of asphalt paint is the most effective and appropriate treatment for sheet lead.