Water damaged ceilings can cause a lot of mess and disruption and prior to plastering it is essential that the water coming through the roof or from a leaking pipe is properly repaired.
A slow water leak over a period of time can cause wooden timber joists to rot and sections of the joist may have to be replaced.
Our preference is to repair the ceiling using new plasterboard. The damaged section should be removed and the joists need to be located in order to screw in the new plasterboard. If the original surface is lathe and plaster, it can be an inch thick and sometimes two layers of plasterboard are required to level with the ceiling.
If necessary, bonding can be used to fill any gaps and acts to join the old ceiling with the new plasterboard. Once this has dried the normal preparation for skimming over the ceiling can be carried out.