How to seal draft through insulation shield

[Kobuk]

I have my pipe going through my ceiling with my 2" air space for my insulation shield. How can I stop the draft of air going up through the insulation shield? Can I cap it on the bottom which would be the ceiling with sheet metal? Or what do others do to stop all of that air from rising through my attic? I know it can't be combustable and will be covered with the trim ring but not sure what works the best. Thanks in advance

 

[begreen]

Normally this is done with a ceiling support box. How are you supporting the chimney? Regardless, a firestop is required when penetrating floors.

 

[Kobuk]

Normally this is done with a ceiling support box. How are you supporting the chimney? Regardless, a firestop is required when penetrating floors.

The pipe is supported at the roof with a bracket. There is only about 3 ft through my vaulted ceiling and a insulation shield goes from the ceiling to the roof but it is basically a sheet metal pipe 2 inches larger than the metal bestos pipe leaving a large gap for all of my heat to rise up through there. I don't have my trim ring on yet because I am still building.

 

[begreen]

This is one reason why I prefer to see a cathedral ceiling support box used for these installs. Not sure what to tell you. I think I would be tempted to loosely pack some Roxul around the bottom edge until you can trim it.

 

[Kobuk]

I was kind of thinking of cutting a 8 in hole in a piece of tin and screwing it to the ceiling then sealing the small gap next to the pipe with high temp silicone. That way there is no combustable material and no air leak through the insulation shield. Then when I finish the ceiling and put on the trim ring it will be covered.