Someone had the bright idea of using their trusty hammer as a shim, I’m guessing, under a second floor bathroom after doing a repair that required opening up the floor. We discovered this while pulling down the insulation and dropped ceiling to bring our garage up to code, since the PO finished the area above the garage 20-something years ago without properly supporting the floor or fireproofing the ceiling and walls. We discover something new to marvel at (and repair) almost every week since we bought the money pit five months ago.