I used to pick up a lot of these jobs in the Norfolk Va. area. (Ghent) I pass on most of them now unless they agree to rip out, or let me laminate some 1/4" over the old work. They also get really pizzy with me when refuse to warranty any work done on loose plaster lathe walls.
But in your case if the plaster is still solid to the lathes:
1. Walk the walls with a 4-6 foot level and mark off the high spots with a marker
2. You can knick off smaller high spots with a sharp drywall hammer or a 1 1/2" sharp framing chisel by keeping the tools at a very low angle. Don't use any sort of grinding unless you have tested for lead paint.
3. Plaster weld the wall and let it dry. The stuff I use can be applied with a roller.
4. Mix up a bag of (45 or 90) minute hot mud at a time (
sometimes 2)
5. You have already indicated the high spots when you walked the wall.
6. Apply the mud to the wall at shallow areas as thick as you can to the point where it looks like its going to fall off.
7. Use a 3-4 foot spreading tool to fill the shallow areas. I use a hard rubber squeegee that I got off a concrete finishing guy. You can use anything that works though. I even used a piece of baseboard one time.
8. Use a dragging motion to spread the mud. I work from the floor to the ceiling to keep the excess mud on top of my spreader while I'm working it. Don't fuss over any voids.......you can fill them later.
Keep in mind that this is only for killing off the shallows, and you will still need to fine tune the wall with a with a finishing knife or trowel. The whole idea is to give the wall the
appearance of being flat. Old plaster walls were never really flat to begin with. Once you get up to speed, you can easily do a 12' x 14' room in a couple hours.
I like to use USG Diamond veneer over repairs like this. You can lay it on smooth, swirl, stomp, and with or without sand. Just add a little retarder or it will cook off fast. It will brown out after a couple days but don't let that scare you.
http://www.usg.com/content/usgcom/e...products/finishes/plasters/diamondveneerfinishanddiamondveneerfinishsanded.html