Probably stupid question - damp

[JustJani]

Which professional do I need to call for a damp patch that has suddenly appeared on an internal upstairs wall? I've got no real idea what's causing it, it's near the bathroom but not in an actual bathroom wall so best guess is a bathroom leak but far from sure.

I live alone and there's no way I'd attempt DIY, I'd have no clue.

Do I get a plumber or a builder or a.n. other?

Have you thought about buying a dehumidifier. They are v effective

Thank you, it's appeared and spread fairly quickly, I first noticed it a couple of weeks ago and since then it's also appeared further up the wall. So the speed makes me think it must be more than condensation.

I would guess a plumber to look for the leak. Do you have emergency cover on your home insurance, it sometimes covers searches for leaks, as it can be quite costly.

Definitely start with a plumber. You need to identify the cause and they’ll be your best bet.

As far as I’m aware, damp experts would get involved with remedial work for properties where damp is widespread and less obviously caused.

Okay thank you, I'll be checking my insurance and attempting to find a plumber tomorrow!

Is the damp patch on the same wall where the shower is in the bathroom? If so, could be a leak with the shower pipework.
If the damp patch is high up the wall, it will likely be from the roof (assuming its a 1st floor bathroom in a house). Have you noticed it worsen with rainfall?
Looks like you found the symptom, there will always be a cause.

I had a leak! Get a plumber to fix the problem and then a roofer if it's the roof. Once it's dry and assuming the plaster is okay you can paint it with damp proof paint and then ordinary paint. Often damp patches look worse than they are because it spreads