A vapor barrier under a metal ceiling is necessary in cold climates or in areas with high humidity. It helps prevent moisture from condensing on the underside of the metal, which can lead to corrosion or rust over time. The barrier acts as a protective layer, ensuring that moisture from the building’s interior does not infiltrate the ceiling system. Additionally, it can improve thermal performance by reducing heat loss. However, the need for a vapor barrier depends on the specific building design, local climate, and insulation requirements. Consulting a professional is recommended to determine the most appropriate solution for your project.
