It is not too hard to repair lath & plaster with original materials. They can still be obtained, but you will have to do some searching to find them. The lath can be repaired and/or replaced, it is simply rough sawn cedar strip, nailed to the vertical wall supports, called studs. Basecoat plaster can be purchased from a building supply company, the local hardware store will not have it in stock. It is quite simple to spread and smooth basecoat, because the final surface does not have to be smooth. Finish coat plaster is the more difficult part of the process. The materials must be of good quality, and in particular the gauging plaster must be dry and free of lumps. You will have to locate a source for finish lime, preferably lime that contains significant magnesium, also known as "dolime". The mineral used to make the best finish lime is dolemite. Be sure to pick up a pound or so of retardant when you purchase finish lime. You will be successful with finish coat plaster if you begin with a small repair, on the order of one or two square feet. Eventually you will acquire confidence in your skills, and be able to do a larger wall repair, say 50 square feet. Plastering a large ceiling will require a combination of skill, strength, and conditioning. Anyone can get the plaster up there, but not everyone will be able to produce an acceptable finish. If you have to do ceiling work, it should be put off until you have gained experience and success at wall repairs. As others have pointed out, your existing plaster might be coated with paint that has lead pigment. Getting this material off the walls, bagged, and into a landfill without exposing yourself to lead dust is possible, but it requires thought and planning. Be aware that vacuum cleaners have an exhaust outlet, and that very fine particles will be ejected from the outlet when the vacuum is in operation. To remove old plaster safely, you must be concerned with the large visible pieces, and also the dust that is too fine to see. Cleanup must be thorough. Young children could pick up the fine particles on their skin, and end up ingesting it when they put their hands in their mouths. The good news is that the raw materials used in plaster repair are not too expensive. If you can supply the labor, the total overall cost might well be under 1000 dollars, even for the extensive repairs you describe above.

I've removed many slat and plaster walls and this is the most efficient\minimal mess technique I have discovered. The fact is, this is a messy job and "bashing walls" is out of the question if you want to minimize the spread of dust and cleanup time. Here's what you need and how to do it: 1. Quality respirator mask (no exceptions). I recommend a $19 dual filter mask from Wal Mart. 2. Thick durable work gloves. 3. Protective plastic goggles (Wal Mart). 4. 1 Large black marker. 5. 10 X 12 thin plastic drop sheets (Wal Mart). 6. 1 flat pry-bar. 7. 1 Drill with half 1/2 inch bit. 8. Reciprocating Saw (any reliable brand will do) with extension chord. 9. 1 stud finder. 10. 1 ladder. 11. Large 96 gallon square trash bin with wheels or durable plastic storage container with wheels (preferably). 12. 1 Shop vacuum. 13. 1 Broom & dustpan 14. A partner to help (needs items 1, 2, & 3). Step 1) Turn off the power in the room that contains the wall you plan on stripping. You do not want to electrocute yourself! If other rooms have power receptacles on a separate fuse you can run an extension chord into the work room to power a flood lamp. Or if it's daylight you're all set ;) Step 2) Remove all wood trim from wall. Using the ladder, stud finder, and the black marker, start about 5" down from the wall\ceiling crease and locate and mark all the wall studs on the wall you plan to strip plaster slats from. Make your stud marks horizontal and 4" wide. Have your partner mark where the stud finder began beeping and where it stopped. Make note of all electrical switches and outlets. If you have multiple plugin outlets on a single wall chances are the wiring will be horizontally ran inside the wall to join the outlets. Use the marker to draw a horizontal line between outlets. You will not cut below or within 5" of the top of this line. Step 3) Cover the floor of the room where you're working with the 10 X 12 plastic. I like to "booth off" the room with plastic by taping 10 X 12 sheets from the ceiling to the floor using blue painters tape as it will not rip your drywall paint\paper when you remove the tape. I tape all joining plastic sheet seems from ceiling to floor and allow a slit for me to walk out during breaks. Step 4) Put on you respirator, goggles and gloves. Make sure your respirator is tight enough not to let air in and the nose bridge is snug on the bridge of your nose. You do not want ancient dust creeping in your mask! A hat is optional if you don't want dust in your hair (ladies). Position the 96 gallon trash can by the ladder and have your partner waiting for you to hand them square slat and plaster section to put into the garbage can. Step 5) Start at the left hand side of the wall. At the top of the ceiling, using the drill and the 1/2" bit, drill a hole on the right end of the 4" stud marking. Only drill a hole in the section your are currently working on. Step 6) Place the blade of the reciprocating saw half way in the 1/2" hole you drilled earlier and begin sawing downward. gently add downward pressure to the saw, don't force the saw, let the saw do the work. It should cut through like butter. Keep your cut line as straight up-and-down as possible. You can also steer the saw close to the parallel wall stud for a closer cut. If the saw blade pops out or is hard to move, chances are you're cutting into a wall stud. Stop, evaluate the situation (using a flashlight), and reposition and continue to cut just the slats and plaster. Stop cutting when you're about 2" from the floor. You should now have a semi-straight vertical cut line from ceiling to floor. Step 7) On the ladder, using the pry bar, at the top of the wall, you will pry off your first single square section of wall by using the following technique. At the top of the wall, from left to right, diagonally slide the pry bar (hook end towards you) behind the cut plaster panel and leave the very end of the pry bar(flat end) sticking out at the lower bottom left. With your right hand, firmly grad the upper right of the plaster section, holding the hook end of the pry bar against the back of the plaster wall section. With your left hand, firmly hold the flat end of the pry bar behind the lower left corner of the plaster wall section. Slowly pull the entire panel of plaster towards you keeping the pry bar firmly pressed behind the plaster section you are removing. If you do it correctly you will keep 98% of the plaster in tact and all nails joining the wood slats to the 2 X 4 beam will be pulled out at the same time. Hand the square plaster section to your partner to place in the bottom of the 96 gal plastic trash can. Continue this technique all the way down the cut in the section you are working. You should get the hang of it by the time you're done with the removal of your first section. Step 8) Repeat steps 5 through 7 until the wall is stripped. You may have some remaining nails to remove with the pry bar when you are completely finished with the entire wall. Step 10) Pick up stray pieces of plaster and slats when you're finished. Gently roll up the plastics sheets being careful not to spread the dust; dispose of the plastic. Sweep and vacuum and remaining dust and debre that escaped the plastic. You may need to make several trips to the waste transfer station with the trash can to dispose of the slat and plaster or you can pay someone to pick it up. I have this technique down to where I can strip a 10 x 8 wall in 60 min with little or no mess on the floor. Have fun, be safe.

Use Durbond90, or if you are not experienced with plaster reapir yet, Easysand90. These are 'setting type' joint compounds that come as a powder and are mixed with water. Mix them as thick as peanut butter for larger cracks, a little thinner for smaller cracks. The less water you use the less shrinkage on setting. They do not harden by drying like pre-mixed mud. The number is the approximate hardening time in minutes. Both longer (240 Min) and shorter (20 min) with some additional steps available. Durabond is as hard as plaster and cannot be sanded well at all, so be careful.

To get access to the defective lath & plaster, you will have to detach the cabinet and move it out of the way. But, before you move the cabinet, you will have to turn off the hot and cold water, and then disconnect the plumbing, as necessary. There should be shut-off valves under the sink. It is possible to remove the soft and cracked plaster, and replace it with fresh plaster. After moving the cabinet back into place, you can put up some new tile, and do a thorough job of sealing the tile and cabinet, so water does not get to the wall. All of this is doable, but it sounds like quite a project. The kitchen sink could be out of commission for a few days...