What kind of material is my wall made out of?

What I know so far

  • It's not traditional drywall over wooden studs.
  • Running my stud finder over it results in weird readings indicating the entire wall is a stud.
  • My cheap basic drill and bits struggle to bite into the wall.
  • This wall in particular is exterior facing.
  • My condo is in a mid-rise building that was built in 1965 in New York City.

What material I am looking at? I am leaning toward it being cinder block, but I don't see any seams where I expect the mortar to be.

EDIT: It indeed looks to be cinder block.

Rough photo of the wall. Will try to get a better shot at the next opportunity

  • Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking.
    – Community Bot
    Mar 1, 2022 at 3:50
  • 1
    The picture is poor. You can add pictures that are better lit, in focus and more views. Initially it looks like drywall facing you, metal studs, and cinder block facing out. What makes you think it's not those things?
    – jay613
    Mar 1, 2022 at 11:45

2 Answers 2


Looks like a standard cinder block wall to me. The green box highlights a block, while the red arrow points to a mortar joint:

annotated version of OP's picture

There appears to be some sort of corner bead directly attached to the corner of the block (just to the right of the red arrow's tail). Perhaps this was a corner bead for an original skim-coat of plaster directly over the block.

Further to the right is the current interior surface wall. This appears to be some sort of particle board with a skim-coat of plaster. This is unusual to me, but that doesn't mean it was never done.

To the left appear to be metal studs, perhaps for an adjacent wall interior partition wall.

  • 1
    Thank you for pointing out the mortar joint.The photo was taken inside of the fan-coil unit. The metal studs are just the frame for the fan coil where the fan case would be the left of the photo. The bead on the right is the gap filler between the case and the wall. Mar 2, 2022 at 19:35

Looks very much like fibreboard. (various local names). A manufactured wood product.

Keep it dry.

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