"Broadback" wrote in message
...
I have remove an old airing cupboard from a bedroom. The plaster was
not existent. I put plasterboard over, thinking I could then skim on top
and make good. Sadly the plasterboard is well below the level of the
existing plaster,

How far under. If 10mm use another sheet of plasterboard then skim, else
use bonding coat then skim.