I recently moved into a mid-terrace house, built c 1885, which had a lot of refurbishment work done a year ago. Over the past few weeks a small damp patch has appeared on the hall wall about 1.5 feet from the front door and roughly a third of the way up (just above the dado rail, I'm not sure if this was new last year or was already there). I have checked with my neighbour and their wall is completely dry. The patch gets worse when it rains so I thought it may be to do with the roof, however the patch is isolated right in the middle of the wall and if it was the roof surely it would appear at the top or the whole way down?
Any suggestions? Should I call in a damp specialised or a roofer?
Thanks!