Hi GBA,

I’m building a home in NY’s Hudson Valley, climate zone 6A. I’m installing 6 mil poly on the ceiling as a vapor barrier required by my building department in preparation for blown-in cellulose attic insulation. I’ve read the GBA articles “Do I Need a Vapor Retarder” and “Vapor Retarders and Vapor Barriers.” From what I understood, this poly vapor barrier may not be essential but I’ll do it if my local code official requires it, and it will help create a seal to stop loose cellulose from falling through the ceiling around penetrations (light fixtures, ceiling mounted mini-split head units, etc), and perhaps will be more useful as an air barrier once I’ve taped the poly around each penetration.

My question is: Is it worthwhile to tape the poly to the top plates all around the perimeter of each room before we install the ceiling drywall? Or will the pressure of the ceiling drywall create enough of a seal between the poly and ceiling framing that taping the perimeter would be redundant? I’m keeping in mind that this could take several rolls of tape and a few hours of labor. 
It may be useful to note that I plan to caulk the wall drywall to the top plate perimeter of each room as an air sealing measure.