We had a phone cal from a landlord to say he had a ceiling issue where the Flat above had a leak and had come through the ceiling, as the tenant had been put into an Airbnb we treated this one as an emergency repair to get the tenant back in and her dog as soon as possible, we had to insulate the ceiling as there wasn’t any in place and because the ceiling had already been over-boarded before we had to take that away first as it was completely saturated with water and just crumbled on removal, we had to remove a section of lathes to get access to insert the rockwool insulation, as we couldn’t remove the full ceiling due to the gaps it would of created around the perimeter of the wall-ceiling.
We then plaster-boarded over the ceiling with 12.5mm plasterboard and screwed it into the joists, skrim taped the joints and plastered it over twice with multi finish plaster.