Have you found the studs, using a stud finder? If your building has them, that's what you want--the studs. also, to throw another idea into the mix, my 1921 apartment building (a co-op, which means I own my apt, which means i don't need my landlord's permission to put holes in the wall) does not have studs OR wood lathe. It's plaster (about 3/4" to 1" thick) over metal, over brick. No brick on the INSIDE walls; I think those are either true plasterboard or plaster brick, and they hold themselves up; again, no studs. Don't ask me why, or how it all hands together, but it's been standing quite sturdily since 1921 and there are NO studs. Framing around doors, but no studs. To install Elfa-type shelving, we used a hammer drill to drill into the brick (about 3 inches below the surface of the plaster) and Tapcon screws (intended for installation in concrete) to fasten things to the brick itself. (I thought I had found a stud, drilled into it, and discovered it was the BX cable for the electrical wires--fortunately, I was acting sort of gingerly and didn't pierce the BX) I *did* however hit a gap and the brick (which I couldn't drill through w/ my wood bit). what helped us a lot was that someone else in our building had renovated, and had pictures of the "inside" of the walls (there isn't an inside, really). And, that my "uncle" had run into this construction before as well; fortunately I called him for advice, or happened to speak to him on the phone as we were trying to figure out where the heck the studs were. Ask around the building and see what other people have done, and what they know about its consstruction. (if you're renting, you could ask your landlord,) Also call anyone you know who has done DIY in a SIMILAR AGE of building. I will say that our kitchen cabinets are mounted in the plaster-brick or plasterboard walls w/ anchors, and they're very very sturdy.

I have a single very expensive stud finder that works on plaster, but it will mess up if expanded metal is present. Expanded metal was used to strengthen interior corners, hold metal bead on exterior corners, and even as the entire lathe in place of wood strips. By a couple 1/16 inch drill bits and start hunting. While nominally on 16 inch centers, older house often wander a little. Measuring can give you a place to start drilling, but you need to verify the stud location at the exact height you want to anchor. The lightweight spackling putty makes short work of filling the small holes. the drills will quickly be dulled, and not be useful for anything else without sharpening. Save them for future use. They can be pretty dull and still work in plaster. The plaster will

latest thought is to rough up the plaster with sandpaper and use liquid nails to glue the furring strips to the wall, without screws. liquid nails doesn't dry hard so I would think it would not be great at conducting sound. That, in combination with the Green Glue between the drywall layers, should suffice, if I caulk everything well. Yes some sound will go up through their ceiling and down through mine, and a little bit from below the floor, perhaps, but not much. I'll get short enough screws so they don't go through to the plaster. I'm going to seat the bottom course of drywall in a strip of foam pipe insulation and then cut the excess. That should also take a little weight off the wall.

Four Toggle Bolts properly installed would be fine to hold up the right cabinet without screwing into a stud at all. The problem is the "properly" part as there is some skill in drilling the correct size hole and not tearing up the paper on the back of the drywall. Hitting the stud on the left with good quality hardware makes this easy. Again, good quality hardware like GRK Cabinet screws going into the studs 1.5" will be plenty strong. If you can get 4 vertical on the left, the limiting factor with 150 pounds in the cabinet will be the strength of the cabinet. Add a couple toggle bolts on the right and you are solid. Add a couple longer screws driven in at an angle to hit the stud off the right side and the limiting factor again will be the cabinet. With a big assortment of hardware and tools, I could hang a cabinet that size and be comfortable putting 500 pounds in it. Cutting a large hole to attach lumber to the existing stud is a lot of work with plaster covered drywall. If you do that don't use plywood unless you want to glue it to the back of the drywall. Plywood does not take screws in the edge very well unless you buy high quality baltic birch ply. Doug Fir or even "whitewood" is the way to go when using screws at right angles.