You talking about old pipes that aren't in use any more?
Water supply comes in from our kitchen and we use to have old CH pipes under the ground but they were made redundant and they all run above ground now. The floor was tested for moisture last year and it passed as dry
only thing I could think of would be CH pipes but theres no leak, boiler hasn't lost any pressure.
Floor next to it is concrete/screed and thats bone dry :unsure:
No, existing internal wall between two rooms bang in the middle of in a Victorian home. Just been knocked through in the past. No signs of the same damp patch anywhere else it seems