Hi All,

First time poster.

I have a house in south florida that was purchased end of 2008. I need to add more insulation in the attic. Currently there is only about an R-11 in most places but there are areas where there is none. My plan is to add R-19 with Kraft facing in the areas where there is no insulation and then add an R-30 (unfaced) on top of all running it perpendicular to the R-11/19. I will be using all batting.
Now my question is does the faced insulation actually provide a vapor barrier and/or air sealing? The reason I ask is that besides keeping the AC in and heat out I am also trying to keep the humidity out as well. The existing insulation is faced.
So if the facing of the insulation really does provide a vapor / air barrier am I defeating the purpose of the facing by just laying it between the joist as opposed to stapling it to the joist face?

Any advice is appreciated.