u/Full_Yard5554

I’m trying to screw in a hook for a hanging lamp and want to find a joist. Problem is that I can’t find one (as evidenced by the dozen holes). When I poke through each of the holes, there’s something that stops me about 1.5 inches up. Could there be a layer of plywood between the ceiling and the joists? Or am I just doing something wrong? Stud finders don’t work on this ceiling. It just lights up red the entire time. I’ve also tried using a strong fishing magnet, and that doesn’t work either, but it does work on the wall paneling.