I had a leak last year from my hot water tank in the loft that flooded through the bedroom ceiling. The tank is fully repaired but I now want to get the ceiling fixed. I have several long cracks along the ceiling and I have gently pulled away some of the (what I presume is) plaster and it looks beyond repair. Do I need to get all the existing plaster on the ceiling removed and then replastered? Is this 3-4mm layer actually plaster? I want to know what I'm talking about when I phone up for quotes and would like to know what I actually need done as I would like to get a proper job done. Any help and advice would be greatly appreciated.