Walls – What’s this metal thing in the wall where the studs should be, and how to put a shelf on it

metalshelvingstudswalls

I'm attempting to mount a shelving system (specifically, a Rubbermaid single-track adjustable shelf) to a wall and am running into something quite strange.

Here's what I know:

  • Studfinder appears to show studs at 16" intervals.
  • Upon drilling a pilot hole on one of these intervals, the bit pops
    right through the 1/2" drywall, passes without resistance through a
    small bit of free space, then runs into something hard to drill
    through.
  • Removing the bit from the drill and manually poking the
    offending substance produces an airy sound, like a big metal plate.
  • Drilling a few feet upward at the same horizontal
    position yields the same result.

The wall is an interior wall in a recently-built high-rise apartment building shared between two apartments.

My questions:

  • What's this metal thing I'm hitting? (I doubt it's a protective plate, as it spans the height of the wall, and sources say a metal stud should be "easy to drill through", which this is not.)
  • Why am I (apparently) finding a gap behind the drywall and no stud at these 16" intervals?
  • What are my options for mounting this shelf now? (Toggle bolts?)

Further testing I plan to try:

  • Scanning wall with a strong magnet (my hard drive magnet hasn't shown me anything yet…)
  • …yeah, I'm out of ideas.

Thanks in advance!

Best Answer

Given that this wall separates two apartments in recent construction, the wall you're drilling is likely not to be "normal" familiar construction. It's probably some kind of "area separation wall" designed firstly to limit the spread of fire and secondly to limit the spread of noise between apartments. You might do well to seek information from building management as to the construction of that wall to ensure that you don't compromise its fire resistance characteristics.

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