Moved into our house in may. There were some water marks on the walls in the kitchen which the home survey and also a separate plumber said we're essentially old and ok, just maybe a burst pipe previously that was now fixed. We painted the walls in October, put some stain protector over the water marks and all was fine.
Today I've noticed they are back! Also in places they look dirty and orange in colour. The water is not flowing out at all or even dripping. I will attached a photo. The wall they are on connects to the conservatory which has a very old underfloor heating system in which seems to work but we've only put on a couple of times.
Anyway I don't really want to call a plumber or engineer until new year if poss. But does anyone have experience or and idea of what's going on??
Thanks