I own a flat that tenants have made a bit of a mess of. The stud walls are covered with 12.5mm plasterboard which has been directly painted - no plaster skim coat. One of the sockets has been ripped out and there's a couple of holes kicked in the plasterboard near the floor as well.
I'll have to cut the damaged plasterboard out to the centre of the adjacent studs, put some noggins in and screw in replacement board. Should I use 9.5mm plasterboard and skim over with plaster to get the same level as the surrounding board or use 12.5mm?
If I use 12.5mm how do I get a neat join? I can't use scrim tape because that will stand proud on the surrounding board. Should I try to cut the replacement board to a tight fit in the hole or should I deliberately leave a few mm all round to take some filler. If so, how wide should the gap be? Should I leave square edges on the replacement board or should I chamfer edges on the existing and replacement board to leave a Vee for the filler.
Thanks for any suggestions.