Clearance to Combustibles Question

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New Member
Nov 27, 2023
New York
I am having an alcove built to house a Hearthstone GM60. The Alcove is being built to the proper clearances in the GM owners manual. I am utilizing an existing masonry chimney that is outside of the house. It measures 20" x 20" exterior. It has a clay liner with inside dimensions of 8.25" x 8.25" and i am guessing an 1"+ airspace around that. I am hoping to pass a snout to a tee which will be connected to an insulated liner. Will I have clearance issues with the wall (in orange)? Looks like the chimney was built up against the lap siding of the exterior of the house.

Clearance to Combustibles Question
That is the intent of insulating the liner. It directly addresses this concern.
That is the intent of insulating the liner. It directly addresses this concern.

Sorry, I should have made my question more clear. I am not concerned with the insulated liner. I am concerned about the snout going into the existing masonry chimney. I plan on insulating the snout as well. However do I have enough clearance around the snout, especially to that exterior house wall the is up against the chimney?
Your thimble should have listed clearances. The one I installed had an insulation donut that fit inside a 16” on center stud bay.
Exactly, this is the intent of the insulated thimble. As long as it's installed per directions, the snout can safely pass thru it and between the studs.