Great question — answering as the UphillTech team:
Presumably you could put a large wooden plank on top of the stone mantle. So, if the mantle is say 10" wide, and your hangers need an inch to clamp to, you set a "2x12" plank on there (actual dimensions of 1-1/2 x 11-1/4 inches, typically - not even 11-1/2 inches these days on stuff that size, usually.) || ||=========== Board to hang stockings from ||GGGGGGGG Granite Mantel ||GGGGGGGG Granite ||GGGGGGGG Granite BBBBB Presumed brick, could be stone (fireplace) BBBBB Presumed brick, could be stone (fireplace) BBBBB Presumed brick, could be stone (fireplace) BBBBB Presumed brick, could be stone (fireplace) ----- Top of fireplace opening If your stockings are dreadfully heavy, set some weights...
Full answer by Ecnerwal: https://diy.stackexchange.com/a/261676 (CC BY-SA 4.0).
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