Thanks, completely agree you have to fix the moisture issue. I’ve definitely had plaster repairs fail in this way when leaks persist. I guess my point was that it’s been preferable in my experience to go the plaster route and deal with this rather than the effects of mold growth in the walls. You always “think” you fixed the underlying cause of a leak in an old building, but sometimes it’s less apparent or there are multiple causes. I’m getting PTSD thinking about managing this leased 120 room 1909 San Francisco nightmare.

I used to manage an old building and this is the way, but there is one problem: leaks. If there really is a leak issue, that drywall is going to mold, turn black, and stink up your apartment.

Old buildings have lots of leaks: old galvanized drain lines, internal roof drains, rainwater intrusion from rotted tin lintels, poorly sealed ancient windows, retrofitted shower pans on old ass flooors, etc. from my experience, catching the leak and fixing it was one thing, but ripping apart walls to find mold from old Sheetrock repairs and abating that was a nightmare (and potentially a reoccurring one).

Plaster doesn’t rot, just gets wet and dries out.