I have seen some guidance on rock lath repair, but nothing about matching wall surface where a new door has been installed.

I put a new double bifold doorway in an existing wall in my 1954 house, cutting through a bunch of rock lath to install new king studs, jack studs, and header. Before I install the door jams and casing I must figure out how to make the prior wall match to fit up to the casing.

What is odd is that the rock lath is slightly more than an inch deep on one side of the new doorway, but half an inch on the other. (Rough-in doorway is 50 inches wide, 82 inches tall.)

So, do I worry about recreating a corner for beneath the future casing, or just build out to match the existing rock lath wall and cover the gaps with casing? Can I consider extra-wide casing to help cover some of the raw space?

I have a sheet of half-inch plywood that is leftover from the flooring; could I cut it into strips to screw onto my stud door framing to fill in, and apply sheetrock mud on top of that to get a flush wall surface? Do I do that and install wire mesh atop the plywood to hold the mud? Do I actually use plaster instead of drywall mud?

I am stuck, trying to figure out the best way to make this look good.

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  • This is an awful lot of questions in one. At a minimum, it could do with an edit for some formatting to make it easier to digest everything you've asked.
    – FreeMan
    Commented Jan 3, 2022 at 15:28

2 Answers 2


I have the same rock-lath throughout my 1940 home.

Since it's an inch deep I would:

  1. Double up some 1/2" drywall
  2. If the paint is semi-gloss then rough it up with some 120-grit sandpaper so that mud will adhere properly
  3. Apply mud
  4. Apply joint tape
  5. Apply mud and sand until you have a satisfactory result

Don't believe me? Look up skim coating.


You can use what in the UK is called plaster bead or skim bead.
This comes in various sizes & styles & fits over the edge before the final coat goes on. The finished corner is the edge of the bead itself, which sticks up slightly, giving you the perfect corner.

If you lay it over the edge we can see in the image, you'd have to fade the layer to hide it. If you chop back a little to the depth & thickness of the bead you can get the end result flat.

The beads come in various styles to suit different corner types…

enter image description here enter image description here

There's also a type called thin coat bead, which can be used just at the skim [final coat] rather than in the browning [US mud?]

enter image description here

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