femurphy77
Grandmaster
To take this a step further it may be advantageous to talk to an insulation contractor. They can foam the entire common wall which would definitely inhibit odors through the wall. If there is a wall separating the attic space it would need to be foamed as well.Common Walls are the problem. The Smoke may be infiltrating through the Electrical Switches and Outlets on those walls. You stated it was worse when the Heat /AC runs. I'd start by sealing all the protrusions on the Common walls. Calk or Spray Foam (Great Stuff) all the Electrical Boxes where the wires enter and around any Plumbing Pipes. If there is a Duct in the Attic for make up air it may be the source of infiltration.