Do you need a vapor barrier for tongue and groove ceilings?

Yes, a vapor barrier is generally recommended for tongue and groove ceilings, especially in areas with high humidity or significant temperature fluctuations. The barrier helps prevent moisture from penetrating the ceiling assembly, which can lead to mold growth, wood rot, and structural damage. Ensure that the vapor barrier is installed on the warm side of the ceiling to effectively reduce condensation. Always check local building codes and guidelines for specific requirements.