This comes up because I am replastering a ceiling in my 1904 home. I took down a sagging and cracked wood lath and 3 coat plaster ceiling.
I am going back with 3 coat and plaster over ribbed lath. I was talking with the plaster who I will be working with and we discussed the need to put Kraft paper or polyethylene vapor barrier over the bottom of the ceiling joists. The thought of doing this only came up from an article I read at http://www.nps.gov/history/hps/tps/briefs/brief21.htm, which states to do this.
I can understand why they would want that done if the ceiling you are plastering is below an attic or unheated/conditioned space and maybe this is what the article is simply referring to.
My situation puts that ceiling below a 2nd story room that is heated and cooled. So I believe that in my sitation I won't have to worry about condensation on the joists.
Please provide your experience and insights into this if you would.