I'd like to put upright brackets above my sewing table, but I can't seem to locate the studs. The wall is shared with my neighbor in an apartment building. My stud finder was giving me some inconclusive/uneven reads, so I used rare earth magnets to try to locate the studs. The dots indicate where there are nail/screw heads. They are anywhere from 8-12 inches apart horizontally and about 24" apart vertically.
Does this mean there are no studs? Can I drill into what appears to be horizontal studs?