I am about to install some batt insulation in an old ceiling where the joist placement must have been determined by the number of remaining boards on the job site. Meaning absolutely nothing is 16" CC.
I am going to use unfaced batts as they are much easier to trim to fit. Then I am thinking of using 4 mil plastic off the roll stapled to the joists for the vapor barrier. This is quite common in wall areas but I have never done or seen it in a ceiling application.
Comments. Suggestions.
Colbyt