[Shadowdoc]

Recently purchased a 200-year-old church that has plaster on brick walls. As shown in the pictures,

there are many spots where the topcoat appears to have peeled off. Previous owners just painted over it and I was wondering how to repair this and what materials would I use.

 

[Stephen0220]

Spray with Kills to seal the wall, then use Easy Sand (either 20, 45, or 90, doesn't really matter, the number just represents setting times), then top with All Purpose. All Purpose (Dark Green Lid) has more glue in it than other topping compounds. I do suggest that you make your patch rather large to accommodate the lump that will be created.
Also, be sure to scrape as much loose paint and debris before any of these steps
hope this helps!

 

[Shadowdoc]

Spray with Kills to seal the wall, then use Easy Sand (either 20, 45, or 90, doesn't really matter, the number just represents setting times), then top with All Purpose. All Purpose (Dark Green Lid) has more glue in it than other topping compounds. I do suggest that you make your patch rather large to accommodate the lump that will be created.
Also, be sure to scrape as much loose paint and debris before any of these steps
hope this helps!

Thank you. That helps a great deal. I’ll try on a small spot first and go from there. I appreciate your reply.
M

 

[FibaFuse]

Recently purchased a 200-year-old church that has plaster on brick walls. As shown in the pictures, View attachment 41605 View attachment 41606 there are many spots where the topcoat appears to have peeled off. Previous owners just painted over it and I was wondering how to repair this and what materials would I use.

Have you heard of FibaFuse Wall Repair Fabric? It comes in 36" x 75' or 150' rolls and is ideal for resurfacing damaged plaster walls. It looks like you could benefit from using it on this job.

Check out this video for more details.
https://www.youtube.com/watch?v=2wFcOkOCogE

 

[endo_alley]

It looks like you have some effloressence from ambient moisture pulling salts to the surface. Doesnt hurt to wash this off with proper solution prior to priming and repair.