This is a 90 year old lath and plaster wall that was cut into to install a thermostat. The hole is 1.5" by 14".

hole in plaster

Should we use:

  • drywall patch
  • mesh tape and joint compound
  • just plaster
  • something else?

If plaster, which type (Plaster of Paris or Lime Plaster) or brand do you recommend?

Also, do I need to put anything in front of the black cord before patching?


  • What is the black cord?, part of the thermostat?
    – JACK
    Dec 11, 2019 at 0:51
  • presumably, yeah.
    – jwezorek
    Dec 11, 2019 at 18:18

2 Answers 2


I have done a lot of repairs like this, I usually use some kind of grinder or belt sander to bevel the edges of the area , then use hot mud to fill 3/4 of the depth once the hot mud is dry then I use mesh and mud to fill the remaining area and the mesh to bridge the gap (reduces cracking) after that I will sand and use topping mud for a quick final layer to match the existing surface, prime and cover paint is the last step. The res on the photo I can’t quite tell the pattern but matching is a bit easier if the base is solid, if you don’t use mesh or tape below the surface it WILL crack on those edges. Multiple layers something to bridge the edge below the surface and matching the texture on the top will make it look like a pro repair.

  • What is "hot mud" (British English speaker here). I have deduced from context that "mud" is "gypsum plaster" Dec 11, 2019 at 11:57
  • 1
    Hot mud is a fast setting Sheetrock mud, it usually sets in 1 hour some brands in 15 minutes. Regular mud or patching compound will shrink if you get a tub of that it may take 3 layers as it shrinks and cracks if two thick.
    – Ed Beal
    Dec 11, 2019 at 14:57
  • 1
    Make sure the existing plaster is securely fastened to the lath....
    – JACK
    Dec 11, 2019 at 17:11
  • Jack is correct I usually shoot a couple screws into the lath that secures the mud. As I always have sheet rock screws I put those in and not screwed all the way in or the head just below the surface of the plaster.
    – Ed Beal
    Dec 11, 2019 at 20:22

Make the area bigger to savely screw down a piece of drywall snug into it. Use mesh tape and plaster after screwing it down with dry wall screw. Done. Get a beer.

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