Roofing help

Hi all.

I was wondering if you may be able to help me with something, our house was built in the 1940's. The roof tiles as far as we know are asbestos.

A few years ago we got the attic converted to a velux, the roof itself doesnt have any plastic sheeting, although it does have insulation. A few days ago I was in the attic and I noticed that there was water running down both sides of the walls.

The problem is that the room is now a bedroom for my son, he has two cats which jump onto the roof alot and play about, I went around the back and it looks like some of the moss has been removed and the slates are exposed, most likely because of the cats kicking it off, just wondering would this have caused the damage at all?

did your loft conversion conform to building regulations with the appropriate insulation/ventilation installed?

its unlikely cats dislodging moss from a roof would cause water ingress!

condensation would be your best bet.

Has it been your sons bedroom for very long?

If it's in the last year then I agree wholeheartedly with the Alastair, bear in mind that he probably doesn't have the window open now as prob would have done in the summer and of course the central heating is now very likely on and the air will be quite moisture laden

does your roof have ventilation ie soffit vents, slate vents, dry ridge system?sounds like condensation to me, sorry alister didnt read your reply

Your slates are likely to be porous after 69 years... the more wet weather we get the more likely it is your notice the problem.

Reroof , with breathable underlay..etc