damp walls

[cgs2204]

my lounge internal wall has become damp. the lounge floor is wooden and the kitchen floor is concrete.what could be the cause of this. recently my adjoining neighbour has fitted a bathroom in the opposite corner to my damp wall, could this be a cause or could it be a more serious problem and how can i find out.

[Wak]

If the damp is at the bottom of the internal wall then I would have a quick word with the neighbour as the plumbing underneath his new bath could be leaking and he wouldn't know as it will all be boxed in.