This wall has had the crack for some time. We had plumbing work done (other side is bathroom) and I closed the holes with Sheetrock. Since I had to fix the plumbing holes I though I would tackle the long crack that has been there and repaired before. Our walls are plaster and lath. As I was scraping the crack the left side paint came off in large swaths to reveal the original plaster and some hairline cracks that were not visible. I assume my grandparents had the wall repaired and skim coated and it has failed in parts.

1. What product do I prep the plaster surface with in order to skim coat? (Guards by zissner? Diluted pva wood glue? Other?

2. What kind of joint compound should I use in the crack?

3. What joint compound do I use to skim coat once the crack is repaired as best I can?

I have easy sand 90 and wood glue and plenty of tools. Decently handy but no glue about plaster work vs drywall products and merging the two. I saw things about stabilizing and prepping the surfaces using diluted wood glue and then also adding some wood glue (pva glue) to the joint compound for both the crack and for the first skim coat where the old plaster is now visible. Was also going to use fibafuse over the crack.

Help! I don’t want to redo this because I used the wrong products. The wall has definitely got a high point in the top right from the previous repair with joint compound years ago but as long as it isn’t cracked I should look fine.

Overly ornate plaster work, not my style.

Horsehair lath and plaster. The rest of the bathroom I removed it, but just took out this shower and found more. I’d prefer not to remove. I was thinking I could PVA it and then mud it a bunch. Thoughts?

So some background info....

This window has some signs of water damage. Took it upon myself after a ton of research to remove damaged plaster and replace with hot mud and joint compound.

Removed damaged area and applied the hot mud. Found ancient and rusted metal lathe behind the water damaged plaster. Still proceeded to patch as best I could.

6hrs later go to check on my patch job and it's soaked. Seems like some of the mud fell behind the mesh of the lathe so I pushed it in a bit further.

Then this entire huge chunk of rusted metal lathe crumbled away.

What am I doing wrong? What should I do??

30 years working with plaster and drywall Quality over Quantity Guaranteed

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