Chimney breast damp issues

[stevepalace]

Hi if anyone has any help or suggestions i would be really grateful. We have two chimneys,one is in use and one is not. The roof was re tiled last summer. At the moment we are noticing more and more damp patches in the bedrooms on both chimney breasts (see the photos). I'm not sure if it is a flashing issue, condensation, or something else? What could be causing the problems?

 

[^woody^]

If the damp is full width or there abouts and just on the upper floor it's the flashing.

If it's in a defined area which aligns with the flue locations (one side upstairs, the other side downstairs) then it's flue condensation or vertical damp from the open end.

 

[bobasd]

OP,
i assume that no portion of any chimney breast has been removed?
reading the Related Threads below will help you.

pics showing the chimney stacks, stack flashing, and any external chimney breasts will help?
also pics of the active fireplace(s) and the redundant fireplace(s)?

typically,you might have leaking flashing esp at the back gutter or possibly, if they are fitted, with your soakers.
the stack flaunching and pointing are sometimes causes of leaks.

the closet with the clothes - remove all clothes & belongings, & leave the doors open until your difficulties are sorted.
keep stripping all suspect wallpaper.
do you have access to see the chimney breasts in the tight loft space?

there's also the possibility that soot chemicals from unswept/unventilated flues is coming through the chimney breast brickwork and showing as damp signs.?

 

[stevepalace]

HI thanks for all replies. I've had a good look in the attic and there doesn't seem to be any water coming in and the plasterboard above the water mark is bone dry and shows no sign of water. The damp just seems to be on the left hand side of the chimney when looking at it from the inside, however i'm not sure which is the flue side as that chimney has been blocked up. We have vents at the bottom of the chimney and vented cap at the topc. THe house is rendered and no clear signs of cracks etc.