1950's Flat Roof House - Damp upstairs

bonnieprince

Hi

I have a 1950’s built house which is mass concrete and has a flat roof. We refurbished around 10 years ago with internal insulation which was fastened to the batons of the previous plasterboard, I think we used insulated plasterboard (50mm I think).
I have since replaced all windows with triple glaze and the house is well insulated.
My problem is the issue of damp on the walls of the south westerly facing rooms upstairs. The aspect of the house is south facing.
The main bedroom has damp in the south westerly corner at the ceiling and floor level and the box room has damp in the same on the opposite wall and also some damp in the reveal of window.
I have noticed one or two leaks at the front and back of the house which only leak during certain weather conditions (horizontal type rain is the best way of describing it).
My question is this, with the issues I am having do you think the roof would be the source of the damp if water is leaking inside the plasterboard insulation? Any ideas or opinions are very welcome.
thanks

greasepalm

Not a builder but would/could imagine subsidence or a slight crack might have happened.Whats on the flat room?

Unsure if fibreglass roofing could be used as that is easily repairable.

bonnieprince

The roof has felt laid on it, it was on before we bought the house and our neighbour advised that the roof had been done in the previous few years before we bought so could be 15 years plus.
Very possible some cracks in the felt are causing the leaks.
thanks for the input.

greasepalm

Yea coming near end of life as looking at a sloping garage roof with the smooth felt and getting the odd drip depending on direction of wind.

Extension roof can see bubbles and wondering how long before that goes also.