damp walls & plasterboard

[fredinitaly]

I'm turning a storeroom into a living room - usual pre damp course stone walls and floor of a couple of inches of cement on mud. I've put down Visquene and 3 inches of concrete to stop damp coming up through the floor but there are a couple of places where damp comes a few inches up the walls and (at the moment) evaporates. One of the places is in an internal wall and the house is surrounded by concrete so the damp is coming up from the bottom of the walls, not the sides.

My original plan was to put up plasterboard with wooden battens and leave a small gap at top and bottom to provide ventilation. The drawbacks are that the gaps will look pretty strange and also that the convected moist air will collect in the room and perhaps require a dehumidifier.

Plan B is to seal the plasterboard top and bottom and put a grille in the plasterboard at one end of the room and an airpump, like in a bathroom, on the outside and at the bottom of the opposite wall. If I switch this pump on periodically it should draw dry air behind the plasterboard, past the damp spots and out of the room. I realise this sounds a little unusual but it seems a better way to provide ventilation.

I would be grateful for any comments and suggestions.

Thanks