Sudden damp patch on bedroom wall

[ThisMellowLemonZebra]

Hoping for some advice on what to do next. We have lived in our house for 7 years and never had any damp in the bedroom but today I noticed a patch on the wall its not mould its definitely a damp patch. I checked outside and it is where an airbrick has been sealed. How do I resolve this, any ideas please?

If the sealed air brick needs breaking out and replacing with either a new air brick or a vent, it would need the right kind of chisel and hammer to break it out carefully, the old mortar removed, then new mortar applied and a new air brick inserted.

I'm guessing a builder or a brickie would do it.

You might also want to check that there's nothing else that could be causing the damp patch, other than the sealed air brick. When we had a sudden damp patch on our bedroom wall it was caused by water that was constantly running down the wall from wonky guttering outside.

Much more likely. The point of water ingress may be some distance from the damp patch as well. The sealant around window frames can also be a good entry point for water.