Something on the door

[vcfromhk]

Hi any clue what this is? This is a new house we bought and not sure what this is

No but as a new house, there’s 2 years for all problems to be sorted by the house builder- give them a call

I mean it's a old house we just bought :) so no warranty

Something is response to damp? Does it move? I get something similar on the pot of an indoor plant. Perhaps there used to be a pot near there?

Looks like a form of mould to me, I see water marks, has the door been wet?

My guess is that the builders have used polyurethane expanding foam on the door frame, and a splodge got onto the door and wasn't cleaned quickly enough. So after it dried, they pulled off the main part of the foam, leaving the bit that was stuck to the surface.

Have a look at this:
https://www.pu-schaum.center/en/pu-in-practical-use/practical-tips-pu-foam/removing-construction-foam/#:~:text=Construction%20foam%20is%20easiest%20to,foam%20residues%20even%20more%20easily.
But do not use a blade as you risk scratching the surface of the wood.

Yes looks like mold. The door is not wet. This particular room has high moisture context. Fortunately I have called someone for damp proofing this room. I will show this to him