Standing seam metal roofs are designed with interlocking seams that rise above the roof surface, providing excellent protection against water infiltration. When considering a re-cover, or adding a new layer over an existing standing seam metal roof, building codes and manufacturer guidelines often have specific rules. Typically, most codes and roofing warranties do not allow installing a new metal roof over an existing metal roof because it can create improper fastening conditions, reduce ventilation, and affect the roof’s thermal performance. Instead, the roof may require the removal of the old metal panels before installing new ones to ensure the new system performs correctly and maintains its warranty. Simply put, standing seam installations rely on tight seams and secure fastening, which can’t be properly achieved if placed over another metal sheet, leading to potential leaks or fastener issues.
For a homeowner doing a safe DIY check, start by inspecting your roof for any signs of wear, loose seams, or fastener issues. If you notice rust, gaps, or difficulty in securing panels, these are signs you might need professional help. It’s best to call a roofer experienced in metal roofing before planning a re-cover to understand local code requirements and manufacturer advice. When talking to your contractor, you can ask: “Will the new roof need to be installed over the existing metal, and if not, what are the removal and disposal steps?” and “How do you ensure the warranty remains valid if we proceed with a re-cover or complete replacement?” These questions help ensure you get a durable, code-compliant roof that will last for decades.