Smart Vapor Barrier For Ceiling in Cold Climate? – GreenBuildingAdvisor

New to me historic home that we are updating.  Zone 5 in Northern MI.  We have a wing with TIG 1.5″ thick oak planking for the entire ceiling.  It’s just TIG planks attached directly to the topside of exposed rafters.  Very cool look.  The living space is primarily heated with a high efficiency wood burning stove but there is also a mini split in that room.  

The attic  above this 30’x 15 room/wing  had never been insulated (rest of house had) since prior owners only used this wing during summers and closed it off during winter.  We are planning to have either cellulose or mineral wool blown in to get it to R49.

The TIG planking is not sealed.  I don’t want insulation and dust drifting down into living area through where the tongues and grooves meet.  

What can we put down on the attic side of the planks to keep dust out of living space before we blow in  the insulation that will still allow vapor to pass when needed?  I don’t want to put down something like poly or insulation board since I am afraid it will trap vapor.

I was looking into smart vapor retarders like Certainteed Membrane.  Looks like just regular 2 nil painters plastic, though.  Would like something more durable if possible.

Any thoughts?   Thank you.