Repaired plasterboard wall needs skimming

[daveaspy]

I have removed a small shower room from a summer house (it leaked, soaking loads of the plasterboard walls and the floor, and was never going to be used again so ripped it all out) which left a lot of wall to repair.

The main wall is about 3m wide and is now about half original skimmed plasterboard (the left half, floor to ceiling) and half new plasterboard. Can/Should I just skim the new area and try to blend it into the old section, or skim the whole wall?

If I should really do the whole wall, what the process? Two layers on the new stuff then another layer over the whole lot? Or can I do a thicker initial layer to bring it close to the old level and the a second coat to cover the whole wall?

 

[Deleted member 292770]

fill the new board out with bonding coat or skim depending how much variation is in it.
then pva the whole area and 2 coat skim.
scrim the join between the old and new and any cracks.
chuck a handful of building sand in your pva and let it go off before skimming.