I live in Independence, Oregon (west of Salem) in a house built in 1998. The attic has blown-in insulation. The attached garage has no insulation in the ceiling and I am planning to add some to lower the heat absorption in the summer time. I notice that the blown-in insulation over the main house has no vapor barrier underneath. Why?
I intent to use batts for the garage portion, how should I install it? With or without a VB?