gap between ceiling and wall

[sarahj]

i should have added this to the other post, but there is a centimeter gap between the ceiling and the wall all the way round the bedroom - the ceiling is a modern gypsum and two of the walls are lime plaster: what should I use to fill the gap, I think the cottage is too simple to take coving.

 

[Gervase]

Is the gap a gaping void - by which I mean is it a lath wall - or is there something solid at the back of it? If it's solid, just use whatever you intend to use for filling the cracks. If there's a void you may have to use something like stiff papier mache or galvanised chicken wire scrunched up to provide a base for the filler.

 

[sarahj]

thanks gervase, its a stone wall, and I think the gap goes upwards into the roof void because on the chimney breast side there is some black sooty stuff coming through. i think the ceiling is plasterboard.