Hi,
one of our ceilings in our 1930s house has started to sag.
One way to repair this (as suggested by our plasterer) is to screw 9.5mm plasterboard over the top then replaster.
This saves all the filth of removing the ceiling, and all the toil of removing/knocking in the original nails.
We were about to start putting up the board this weekend, but noticed that the ceiling had sagged further (the original area which started to fail is held up by an old floorboard and a couple of props).
At least 50% of the ceiling has now sagged by over 2" and I am concerned that trying to push a large area back up with thin plasterboard will just end up with damaged thin plasterboard and a lumpy ceiling.
Waiting for the plasterer to drop by today for a look, but wondered what the worst L&P ceiling was that had been repaired in this way, or if anyone had a disaster story to share :-)
TIA Dave R