My friend's condo was built in 1960 and renovated before she bought it, in 2010 or so. Not long after she moved in, a chunk of plaster on the kitchen ceiling fell off, then a little later the same thing happened to a bit of wall. In both cases, the amount of material that fell off was only ~1-2 mm thick. But it was a fairly large area -- a couple of square feet in both cases.

Here is the bit of ceiling: bad ceiling

And here is the damaged wall: enter image description here

Other interesting factoid: the damaged wall is about 2" thick: it is not a conventional drywall-on-studs construction. Feels and sounds like concrete, but it's not cinder blocks since it's only 2" thick. The ceiling also looks and feels like concrete, but I'm not positive.

Oh, here's a detail of the wall where I think we need to chip away more plaster before doing repairs: wall detail

Any idea what went wrong here? And, more importantly, how do we fix it?

  • what season did this happen? What are the average temperature and humidity in the condo? Are these exterior walls? Is the ceiling below another unit, or is attic above? How well is the place insulated?
    – noybman
    Oct 27, 2018 at 19:15
  • Looks a lot like the original walls and celings in my mid-50's rancher. Plaster over two layers of some sort of cement board. Total wall thickness is ~3/4".
    – SteveSh
    Jan 3, 2020 at 11:47

1 Answer 1


It looks like the skim coat released , this can happen for many reasons the most common is getting wet. On the ceiling it may have been caused from poor prep work when the remodel was done. I don't see evediance in that 1 section that the new coating stuck to the base surface at all. So making sure the surface is clean will be important, I used to always wash walls in kitchens with TSP, trisodiumphosphate, I think a safer type is available than what I used to use but it is a very strong cleaner that removes grease and other surface contamination prior to resurfacing or painting. I think this is what wrong but it could also be from being wet, or if the skim coat was two dry when applied. In any case remove any loose areas clean then recoat if moisture is not found, if moisture is found the leak needs to be fixed first.

  • +1 on your comment. But I would be surprised if the 2010 reno involved new plaster work. Tradesman that can do that kind of work today are rare and expensive. Unless you are unconstrained money-wise, or are trying to preserve some historical significance, don't most renos replace plaster with sheetrock?
    – SteveSh
    Jan 3, 2020 at 11:44
  • I have skim coated several times it is much cheaper and quicker than replacing It also provides a new look and hides repairs in the area as matching texture is difficult at times so a skim coat will do the trick.
    – Ed Beal
    Jan 3, 2020 at 16:23

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