ᐅ Full Renovation: Is Dust Under the Plaster a Serious Defect?

Hello experts,

In some areas under our new plaster, there is dust—how critical is this?

We are currently having our apartment fully renovated. Recently, new plaster was applied, and the workers used a machine for this. Shortly afterwards, an independent tradesperson installed the kitchen connections, which required opening the wall. During this, the plaster partially came loose from the wall surface. The tradesperson pointed this out as a serious issue and advised us to contact the renovator. However, when we first raised the matter, the renovator dismissed it as a minor issue in an email.

Background information:
- Under the loose plaster, the wall is dusty. To me, it seems logical that the plaster won’t bond properly to this, and based on my initial research, this is a mistake.
- The wall was opened using a demolition hammer; could this have caused the plaster to come loose? And also the dust beneath it?
- The dusty layer is also present on the back (wall side) of the loose plaster, but not on the front side.

Questions for you:
- How problematic is this overall? Is repair work urgently needed?
- If it is critical, would it be worthwhile to consult a building surveyor?
- How should I address this with the main renovator?

This is our first condominium and our first experience working with tradespeople, so I don’t want to strain the relationship unnecessarily.

Thank you very much for your advice.

1. Has it been newly plastered? What can be seen in the pictures looks to me like filler compound only, not a 15mm (0.6 inch) thick layer of plaster on masonry.
2. If the plaster (or filler compound?) is peeling off over such a large area, then a defect claim should be submitted and it needs to be redone. The surface preparation might have been inadequate. This should not be your problem—unless it is not redone...

1. Yes, you are of course right. Filler compound. We are still learning.
2. Thank you. We will probably have to do it that way then.