I'll try the airbrick just in case but from what you've said the blocked cavity sounds about right. There's no immediately obvious source of any condensation.
Thanks for the advice.
I have a terraced house set back from my left hand neighbour by 8 feet so obviously my living room hangs out the back of their house by the same amount. From the back corner to my patio doors is another 8 feet.
I am suffering from black markings on the walls although the they feel dry if I...
to reply to all, sorry for the delay I forgot to note my password and threw a tantrum.
It's an age thing.....
The three sockets are an addition to the ring and I changed the wiring to match the diagram. There's a lesson there somewhere I suppose.
Thanks a lot to all for the responses.
I now...
I just finished inserting 3 double sockets into a ring main in a kitchen. They were a slimline socket with 2 earth terminals. I wired them up with the back-box earth and incoming earth in one terminal and the outgoing earth in the second. (It seemed reasonable.) Is this OK as I've since seen the...