repairing plasterboard

[Kit Jackson]

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.

[Andy Burns]

I'd say use the 12.5mm tapered board (or taper it yourself with a surform), use the self adhesive fibreglass scrim tape to prevent cracking, apply joint filler and spread it over about 8", sand to 240 grit and nobody will notice the odd millimetre.

[The Natural Philosopher]

No need to go that far.

simply cut bits to fit the holes toughly, screw up newspapres and slide in a bit of card behind the existing board so the card holds it in place, and use a bit of bonding plaster to glue it in.

Then skim once its set.

bonding plaster is your glue asnd your filler. Then sand back. Then skim a finsihing coat on, or use backing paper over the whole wall.

[tabbypurr]

I might put something solid behind the socket to bond it to the other side as well, like a nice big lump of bonding plaster. Otherwise the repair will be weaker. You could use a bit of bent cardboard encased in a sandwich bag to hold the filler until it sets.

NT

[Dave Plowman (News)]

Square up the hole with a padsaw, etc. Cut a bit of plasterboard that will fit through the new hole but longer. Glue that to the back - if you leave a bit of a gap with the new bit you could get some g-clamps in. Once set cut a patch to fit and glue in place. Then fill the joints.

The socket probably pulled out because it was badly fitted as can happen with dry line boxes.

[RJH]

I've had some success (by my standards) with drylining paper joint tape and joint cement. it sounds unlikely - you'd think it'd stand proud of the plasterboard. But after 3 coats sanded it's very difficult to see the joins.

[John Rumm]

I usually go for thinner patching material (even if its the same thickness notionally but has had a bit of the back scraped away).

Leave a gap all round to allow it to be stuck in place (decorators caulk, no more nails etc). Then use a low denisity quick drying filler to skim it flat (use a wide taping knife to fill and its easy to get a good finish)