I am trying to find some ceiling joists to hang a punching bag from. I have hit one joist, I got it because the track from my garage on the same parallel. I drilled a hole, hit wood, and verified with a nail. I then went 12, 16, and 18 inches and got nothing. I drilled about 2" through the ceiling (cement) and then air.
I tried a stud finder and it seems to be useless.
Any suggestions? I know the pictures arent great but this is what it looks like: