Proudly American
Sketch two paths, contact and runoff
Ask which parts physically meet: cover, flashing, fasteners, brackets and roof panels. Then ask what lies downhill even if it never touches the new metal. The Metal Construction Association describes corrosion risks both where dissimilar metals are joined in damp conditions and where water draining from copper reaches susceptible roofing. A gap between parts does not settle both questions.
Give the roofer the proposed material specification
Find the roof panel manufacturer, finish and installation record if available. Send the chimney contractor’s proposed base metal, coating and fastener description to the responsible roofing professional. Ask whether the combination and the drainage path are accepted for that panel. The roof’s color and the words “premium metal” cannot provide that answer.
Compare alternatives while the material can still be changed
Suppose two prices differ because one proposes copper flashing above an existing coated-steel slope while another proposes the panel maker’s recommended detail. Ask each proposer to document compatibility and how the junction will be completed. If nobody can identify an older roof, state that uncertainty before ordering custom metal. Avoid improvised barriers or sealants as a substitute for the specified assembly.