Hi all:

I'm going to be installing batts into the ceiling (from below) but I'm
not sure if there's a "correct" way to secure the batts to the
joists. The old insulation (insufficient, only 4" in a 9" cavity) was
secured in place by stapling the flanges to the 9" face of the
joists. From the standpoint of having a secure moisture barrier it
seems like the flanges should be stapled to the 1-1/2" faces of the
joists.

Is one method preferred over the other?

TIA.

Tom Young