If you have a plaster or drywall surface that’s beyond repair, you can either remove the existing wall surface or apply new drywall over top of it. To help you decide, here’s what’s involved with each.
If you remove the existing surface, you can apply drywall conventionally: direct to the studs. But you need to tear it off first. If it’s drywall, you can cut out big sections and remove them. But even if it was applied with screws, locating and removing them is difficult, so you’ll need to pry or tear the remainder off the studs. Then remove the fasteners or cut them with a reciprocating saw.
Removing drywall is heavy work, but removing plaster is messier. Plaster rarely comes off in neat sections, and you get a lot of dust.
Either way, you also need to dispose of the material.
Installing drywall directly over the surface may be a good alternative, but there’s extra work here, too. You need to remove bulges in the damaged surface by hammering or sawing out sections, and remove baseboards, ceiling trim, and door and window casing. You can install 1×3″ strapping across the studs to make the wall plumb and provide a big area to take screws. Then, with the power shut off, move any switch or outlet boxes out the level of the new surface.
Once you’ve installed your new drywall, build out door and window jambs to the new surface. Set these back to reveal the edge of the old jamb, as you normally would with door or window casing. This way the repair looks like part of the trim, rather than a patch job. Drill pilot holes before nailing this thin strip in place. If you watch your setbacks, you may be able to use the original casing.