Insulating Behind Non -Combustable Wall

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neubauer6

New Member
Aug 9, 2025
1
Wisconsin
Hello all! I removed my fireplace and had a new chimney liner installed by a mason (old liner was shot). I purchased a Kuma Ashwood stove to replace the fireplace. This left me with the chimney brick exposed in my living room. The mason plans to stud out a wall with steel studs in front of the existing studs and hang Durock to attach the finished stone to. He suggested that I insulate the wall up to the thimble. How would you best accomplish this? I purchased a spray foam kit from Menards, but the instructions say that it can only be used up to 240°. I had also considered pink foam board with spray foam around the edges. Just bought this house and have gotten more than I bargained for!
 

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I would just use standard insulation or the foam board and a vapor barrier then cover with sheetrock. The Ashwood has a 7" rear clearance with double-wall stove pipe connector. It's not going to get closer to the wall than that unless pre-approved by the inspecting authority and then the insurance company. As long as the clearances are properly honored, sheet rock is fine. Use cement board only if the intent is to tile or put a stone or brick veneer on it.