Canned foam around 6″ kitchen exhaust
fall50
| Posted in General Questions on
While I belive I know the answer any safety concerns about using canned foam to seal around metal duct that penetrates through the ceiling. My specific concern is the heat that is generated by the stove however based on the picture I have apprx 3 feet from underside of the fan relative to the 6″ round pipe that travels through ceiling so the highest temps would be right at the inatke on the underside of the fan.
Simply put assuming I get the Dow canned foam that’s fire rated, any concerns about using it above to seal the exhaust pipe above the stove
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See attached pic
M.S.,
The 6-inch duct won't get very hot. There is no reason that you can't have canned spray foam (or better yet, a high-quality European air sealing tape) in contact with the galvanized duct. (Of course, you will want to remove that aluminum foil before you do this air sealing work.)
Thx Martin. To be clear Iam talking about the ceiling plane specifically, foaming around the pipe. I used foil tape on all the "gores" of the pipe itself. Not sure why I would need remove the aluminum foil as that incases the fiberglass insulation ment to insulate the pipe. I would foam around the aluminum sleave to complete the air barrier at the drywall.
I assume you ment remove the aluminum foil so that I could seal the pipe first?
M.S.,
I didn't realize that the aluminum foil was actually a cover for the insulation. The photo shows aluminum foil with a rather crumpled appearance, so I didn't realize it was insulation.
If I were you, I would first tape the foil-covered insulation to the duct, and then air seal the crack between the foil-covered insulation and the drywall.
.
Can foam is fine there. You shouldn't use it on a gas fireplace chimney. That is another matter. The stove vapors and fumes from cooking aren't very hot by time they get sucked up into that duct with all the other air in the house that it pulls with it.