Damp Chimney Breast

[Joe 90]

Large damp patches have been coming through at the top of an old chimney breast in our lounge to the extent that we had the chimney removed to below roof level. This has not eradicated the problem and the roof area and old chimney area in loft appears dry. We live in a detached bunglaow (circa 1930) with roughcast walls which appear ok. Have had several companies around with conflicting ideas. They have quoted for re tiling roof but this is not where the damp seems to be coming from. Any ideas?

[heathfield]

It's always recommended that an unused chimney should be ventilated. Rain on the outside can cause a buildup of damp air inside the chimney space. When the walls cool, the water in the air can condense on the inner wall, causing the damp patches.
It shouldn't be too hard to install a vent at top and bottom. Surprised none of the contractors has mentioned this as a possibility