I'm "simply" (or so I thought) trying to drill holes in my garage wall to put up v-hangers and shelving, but there's some type of metal behind it. Where I first drilled turned out to be just about 1/4-1/2" of concrete before I hit the metal. My stud finder isn't picking it up, even at the hole. Unless it's a solid piece of metal behind it the entire wall? I'm in FL, if that helps understand the construction. So, any thoughts on what I'm looking at back there, and how I should go about accomplishing my "simple" job? If it's a sheet back there, can/should I go into it? Already ruined one masonry bit trying to, not even realizing I was hitting metal. Do I simply need a better stud finder? Thanks much!