Kelly Frauenkron I believe spray foam insulation could offer you the best ability to fully insulate and seal a difficult to reach area like the attic you describe. Much more difficult if it's an existing home. At the eave area, if you have access to this or could make it from the exterior by removing the soffit, you could spray about 1 foot or so of the spray foam inward on the gypsum, and pull it back to seal it up to the vent shoot. Then go in the attic & blow or foam the rest after removal of the existing.
08/09/2011