I'm in the middle of remodling the 2nd floor of our 1955 cape. We found a place where the PO attempted to drill through one of the doubled up floor joists around the stairs. But its not a hole drilled through the side, its drilled from the top down.
The first two small holes only go in about an inch, the third larger hole goes just about all the way through. Is this hole too large? If it is, is it sufficient to bolt another joist, perhaps 4' long, next to the damage? Only the first half of this joist is visible (the section in the knee walls, and a bit into the living space where an old wall was removed), the rest is still under the floor boards.