Dark spots on filigree ceiling

Wet concrete becomes evenly dark.

The pictures clearly show mold growth.

Wet concrete becomes evenly dark.

yes, if you wet it.. when concrete dries, then there is absolutely nothing even anymore....

The pictures clearly show drying concrete... and that is just how it looks...

I clearly do not see any spores!

Joking aside: clearly ... at least for me, erase that word.

Still, I do not see any spores in the photos. Maybe a close-up shot helps with a remote diagnosis, but only maybe.

Regards, Yvonne

Hello, I would like to bring up this topic because I also have stains on the ceiling that I cannot identify.
The filigree ceiling was delivered and installed about 1 year and 2 months ago. About 1 year and 1 month ago, the garage roof was sealed. Shortly before it was sealed, there was heavy rain and the ceiling was relatively wet. Since the garage door could only be installed 6 months ago, the ceiling was able to dry out relatively well. Screed was applied about 9 months ago and the garage remained open for about 2 more months.
I have been waiting for a few weeks now for the stains to go away so I can paint the ceiling, but they do not change. Compared to all other stains I see in the forum, it does not seem to be a leak, as they always look the same, regardless of whether it has rained heavily or not. Also, they are not stains, but rather stripes on the ceiling, and strangely not on all precast parts.
Does anyone have any idea what this could be?

Best regards, Philipp

To shed light on the matter :) Precast ceilings are cast in a mold at the factory and these are residues from the formwork oil. So nothing serious and completely normal ;)

I have been waiting for a few days now for the stains to go away to paint your ceiling, but they are not changing.

Paint over it, you won’t see them later. It was the same for me.