Jennifer writes from Shreveport, Louisiana: "I have an old house with 12"x12" ceiling tiles in the living room and I hate them. The attic is insulated with blown in insulation and rolled fiberglass insulation on top of that. And I'm not familiar with the rules of moisture barriers at all. What I would like to do is apply drywall mud directly on to the existing ceiling tiles and then paint and glaze it and create a stucco look but in doing so I do not want to create an incorrect moisture barrier and cause the ceiling tile to mold underneath the drywall mud and I do not want to cause the room to become even less energy efficient."

Answer: Applying drywall mud to the existing ceiling will not affect the vapor retarder.