Soundproofing an old lathe and plaster ceiling

Good morning

I wish to soundproof the ceilings in a Victorian conversion. The existing ceilings are lathe and plaster that have been either boarded over or skimmed. Using the cornice as a guide the thickness of plaster added is quite considerable on a couple of the ceilings. I have the height to add perhaps 4 inches but could not hang an independent ceiling using new joists and joist hangers. A couple of the rooms are quite large.  Continue reading