Joe writes from Kendall Park, New Jersey: "I own a ranch style home. I have an old layer of insulation in my attic that was installed in the early 1960s. I would like to place a second layer of insulation over the original for added warmth. Most websites recommend that I use an "unfaced" layer to avoid condensation problems. However, the original insulation is so old (it falls apart if you attempt to move it) that I am concerned that there is a not a good existing vapor barrier.

"As a result, should I use faced insulation to create an adequate vapor barrier or should I use unfaced?

"If I choose faced insulation, is there a way to check to see if I do have a condensation problem in between the 2 layers?"

Answer: It would be wise to use unfaced insulation to avoid having a double vapor barrier. Although there may be some holes or tears in the current vapor barrier, that is better than having a second vapor barrier.