We were removing some old wall hooks left by the previous owners, and this one surprised us by being a deep set wall anchor which left a fist sized divot.

Now I have no idea what material this is. It looks like it might be some kind of plaster over gypsum drywall? The outer layer is very coarse and crumbly. This might also explain why I've been having so much trouble getting drywall anchors in the walls.

Any help in identifying it and suggestions on repair would be appreciated.

Wall Hole

  • Looks very asbestos to me. Some kind of fire-rated plaster over gypsum. The flecks in the plaster remind me of vermiculite. Commented Dec 6, 2021 at 23:09
  • How old is your house? If you score the concrete-looking material with a utility knife, does it cut like gypsum/drywall or is it harder?
    – TylerH
    Commented Dec 6, 2021 at 23:10

1 Answer 1


It looks like cement render over over drywall with a plaster veneer over that.

For repair of that don't use a wet "mud" plaster that will take ages to dry at this thickness, use a "hot" plaster instead. This is a dry powder that you mix with water and make a mud that sets hard in under an hour while still moist.

You can add a little white (PVA) glue to aid adhesion and impact resistance. paint some in the hole and add a little to the mix.

It will probably take two or three applications to cover that divot.

Fill to just past level with the existing plaster, sand it flat with a plaster sanding block, once the surface looks dry paint it to match.

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