How essential is the vapor retarder in an attic space?
Mark writes from Baytown, Texas: “How essential is the ‘kraft paper’ vapor barrier in an attic space? I want to add insulation to the attic of my single story home to save more energy. I currently have blown in insulation just over the top of my roof rafters. There is no vapor barrier present between the insulation and the ceiling sheet rock. Should I buy faced insulation bats and install them below the blown-in material, and then reinstalling the blown-in on top of the bats, or by unfaced insulation and simply lay more over the top of the existing? I do want to do the job right.” Answer: Owens Corning recommends using unfaced insulation over any existing insulation. If you are not having any problems with moisture now and the attic space is well ventilated, there is probably no need to have a vapor retarder under the attic insulation.
