Trying to find a ceiling joist in my apartment (if it helps - a fairly modern block built sometime around 2006-08 I think) to screw into - unable to do so though so hoping for some advice. We've tried a stud finder and it gives inconsistent readings all over, and tried knocking/tapping but there's no noticeable difference in sound anywhere but next to the walls. As it's a rented apartment I'd rather not go down the route of exploratory holes but I'm out of ideas!
Could you take a downlight (if fitted) out to see what is there? Out of interest what is it that you want to fix to the joist?