Plaster over concrete - how to patch?

[ekstrom]

I have a 1906 home with a foundation that is composed of poured concrete and granite blocks -- concrete below ground level, and granite above. I would like to fix up an area of the basement to use as a laundry room.

Right now, the basement walls in the laundry area are lined with plaster applied over the concrete. The plaster is broken and crumbling in some areas, but in good condition in other areas. Near the bottom of the wall, there are areas where the concrete has started to crumble and break away. My basement is very dry, so this isn't a water issue.

I'd like to fix up the plaster to get a strong, relatively even and attractive surface. How should I do this? Should I first fix the crumbling concrete? If so, with what kind of cement? How do I apply it to a vertical surface? Then, what kind of plaster should I use? How should I prep the existing plaster before applying the new plaster coat? Any tips or suggestions?