Dave writes from somewhere in the U.S.: "I have an older home built around 1880. The ceilings below the attic are plaster and lathe. I am putting insulation into the rafters above the plaster lathe ceiling (so the floor of the attic). The rafters are 8 inches deep-15 inches wide. Should I use a vapor barrier first? Or batts with a vapor barrier facing down?"

Answer: If I am correct in understanding that the attic is unfinished and there is no insulation at all, I recommend installing Kraft-faced batts with the paper side down as you suggest. If there is already some insulation in place, use unfaced batt insulation instead.