ᐅ Gray spots appearing on the ceiling after moving in

Created on: 25 Mar 2025 07:49
H
Hafenstraße
H
Hafenstraße
25 Mar 2025 07:49
Good morning everyone!

After some of you experts patiently dealt with my silly questions during our construction phase (thanks again!!!), we are now moving on to the first maintenance-related questions.

We have been living here since October 2024. For a few days now, we have noticed small gray spots on two closely located areas on a wall and the ceiling that were not there at the handover. I’ve attached a photo of the ceiling. Directly above the ceiling is our shower, which of course immediately raises the worst-case scenario. The builder has already been informed, but just like during the construction phase, I would like to hear the opinions of uninvolved professionals. What could this be? Is it realistic that this is just the tip of the iceberg and the ceiling is already molding due to a leak above? Or could these be efflorescent contaminants in the paint?

The ceiling is drywall, plastered, wallpapered, and painted. Above it is a hollow space, a beam ceiling with battens and insulation. The house has a controlled ventilation system, with humidity consistently around 30-40 percent. Ideally, the ventilation’s humidity sensor is located right next to the affected area, so it can be confirmed that the room never gets too humid.

We have not painted over or treated the spots in any way yet, to monitor any development. Maybe someone is familiar with this phenomenon, and other explanations besides the described scenario might be possible.

Thanks for your efforts!
Tape measure on white wall during interior construction, small spots visible.