Can anyone recommend: Surveyor

Our roof terrace was worse and we had "damp stains" all through the bedrooms and living area where the ceiling met the walls. We got the whole roof terrace retiled and unfortunately, the dampness continued (due to more bad tiling work). This may have been caused by "wells" in the tiling which accumulated water every time it rained. Parts of the ceiling "got soft" where we could remove damp plaster by hand which felt like loose mud when handled. 

We got the roof terrace retiled a 2nd time three years ago where I oversaw the work myself and it now it appears to be fine.

From the picture I can't say if your roof terrace needs retiling. But, if I were you I'd treat the side tiling* with waterproof solution (available in most paint shops) and monitor its effect. (Cost around €15 - €20 euro). I would advise you clean the internal black marks with cleaning agent and perhaps pain the affected bits. I wouldn't repaint the whole ceiling until I'd be sure all is OK.

*The upright tiles onto the wall of the terrace.

I am no expert, I hasten to add, but after it rains have a look at your tiling and see if the water is coming up through the grouting in the tiles. If it is, I think you'll have to get professional advice as it may be your waterproof "membrane" is leaking.

Another Observation:- It may be your neighbours leak is infecting your premises or vice versa. 

Just to reiterate:- I have no professional qualifications in the building line and what I posted is my opinion only.

This is not an uncommon occurrence here and the most common cause is condensation particularly if its in a bedroom?

Hi the room is my lounge and there is a flat roof above it which is the patio of penthouse. 

Is there a paint which will stop this happening in future ?  I also think it is due to the cold wall/ ceiling as my room faces north which is great in summer but cold in winter.

either a leak in the patio above or,what type of heating do you use in this room,if it is a portable gas heater that could be the problem,each gas bottle puts apx 25litres of water into the atmosphere