Damp chimney breast

[cbms]

Apologies if I am posting this in the wrong section feel free to move it moderators.

We live in a Victorian terrace, there is a big damp patch on the chimney breast in the dinning room at the top, I borrowed a damp meter reader and tested the chimney and the one up stairs and I can not find the direction this would be coming from. The problem is the chimney breast ends in the loft so it is a unusable chimney so I have no idea where this dampness is coming from. What I have found though that is when the builders would have taken the stack down from the room they have just left all the bricks and what ever else in the inside of the chimney.

I have had a look at the roof this seams fine no major leaks or anything so my worry is that for some reason there is some sort of damp in the chimney itself how can this be and can any one please help.

Kind regards

 

[Gobo]

I'm not a builder but I'm pretty sure if they've blocked it up and dropped it down into the loft there should be visible vents on the chimney breast in a least one of the rooms below.
This allows air to pass up and down the empty chimney preventing condensation and thus damp. What could of happened is that the chimney was left uncapped and unused, which was fine until it was dropped into the loft thus stopping any air flow, which the builder might of missed.

Hope this helps

Gob's

 

[cbms]

Thanks Gobo - after reading some of the other threads, I should have said that the dinning room still has an opening and the old fire place still in place so I guess that would be enough ventalation although it did does have an old black back filled with old newspaper in it to stop all the dust falling? and the bedroom one again still has a small original fireplace but I dont think this has been for any air flow. I dont know if this helps my worry is that all the rubble was put in to the stack in the loft and it had blocked a nice air flow in to the loft space.