Repairing wall prior to putting on skirting!

good evening all,

Removed some skirting from a room in my new house and most of the plaster behind has fallen away to reveal the timber frame, I believe I need to bring this out so I can fix the replacement skirting in place when the time comes... Should I use bonding plaster for this?

Secondary where the plaster is damaged above the board line (not back to the timber frame) what's the best way to repair this?

Thanks in advance
Dean

Where the plaster has dropped off below the board line- don't worry about it. If there are gaps between floorboards and walls then stuff some Rockwool down them then fix something the same thickness as the plaster was (probably 12mm or so so OSB or ply strips) to the verticals in the timber frame so your skirtings go back on and sit true.

Where you've dinked the plaster above the board line (presumably with your wrecking bar)- depends how severe the damage is. Worst case is cut out and put a new patch of plasterboard in and skim, most likely is use any old powder filler and sand back to flat.

Thanks