i have damp patches appearing at the top of the chimney breast and on the ceiling above -the chimney stack has been removed but not capped off. Air can flow through into the loft space. The roof has been refelted and retiled above the area of the chimney. There is no visable sign of water ingress in the loft space and the area directly above the chimney in the loft is dry?? this has been like this with no improvement or deteriotation for almost a year now - there is no staining or discolouration to the wall just damp patches. I have checked the area with a protimeter and it gives high reading where the ceiling meets the coving and reduces as it gets lower. The ground floor fireplace is also open and so is the bedroom fireplace allowing a free flow of air. ive covered the loft space in plastic sheeting in an attempt to trace any leaks but this is dry even after rainfall. any help or advice ??? its driving me insane !