Where is the vapor retarder located in a ceiling batt insulation installation?

The vapor retarder is correctly located against the back of the ceiling finish in a ceiling batt insulation installation. This positioning is essential because it helps to prevent moisture from the living space of the home from passing into the insulation and then into the ceiling assembly. By placing the vapor retarder on the warm side of the insulation, it effectively minimizes the risk of condensation forming within the insulation, which can lead to mold growth and structural damage over time.

Positioning it against the back of the ceiling finish allows the vapor retarder to serve its purpose effectively, ensuring that moisture is blocked from entering the insulation layer from the warm side of the house.