Doing repairs yourself, quite oftenyou have to get rid of the old plaster. In some cases, you can limit yourself to partial repairs, but there are times when you have to completely get rid of the previous coverage. For example, if you want to align walls that have large differences. 
Cleaning of the wall from old plaster: a - cleaning with a scraper; b - smoothing by a cleft or a hinged grater; c - diagram of moving the working tool.
Cleaning of walls from old plaster
It will take:
- hammer and chisel;
- putty knife;
- perforator;
- garbage bags;
- glasses and respirator;
- spray.
The first step is to determine whetherget rid of old plaster or not. The wall is checked by tapping. If you find a muffled sound (in many places), then the plaster is unstable, and it is better to remove it. If there are cracks on the wall, then this is clear evidence of poor quality finish. It is necessary to get rid of the previous coating even when the wall has large differences. Since leveling irregularities is much more difficult than plastering the wall again. 
Scheme for removing old plaster. You can clean the wall of the plaster with a hammer and a chisel. This is dusty enough work, so the surface must be thoroughly moistened with water. Then the chisel is installed at a small angle, hit it with a hammer. Thus, pieces of plaster easily repel. It is important not to damage the electrical wiring. If you do not know where it is, it is best to unscrew the plugs while you work. There are cases when the plaster is held so firmly that it is impossible to cope with it using a chisel and a hammer. Then it is better to use a perforator, which is installed a chisel nozzle and switch to the chiselling mode. Do not forget about safety: wear a respirator, goggles and gloves. The puncher is put at an angle, the pieces of plaster begin to chip off, while the chipped pieces are constantly moistened from the spray gun. If the plaster contains a large amount of cement, then it is quite difficult to remove it even with a perforator. In this case, you need a Bulgarian with a nozzle to cut the stone, with it, plaster is cut lengthwise and across (in the form of a rectangle or square), after which it will be easily broken off by a perforator. Do not forget to immediately put the garbage in bags - then you do not have to clean the floors and spend valuable time on additional cleaning. It is also possible to clean the walls of the plaster with a layer-by-layer method (suitable only for a thin layer of finish). First, very well moisturize the surface, then grind it with an abrasive bar soaked in water (easily replaced with sandpaper and grater). This method is not very convenient, because you have to constantly wash the surface of the bar or replace the sandpaper. The task is greatly facilitated if the house has a grinding machine with an abrasive disc, with its help it is very easy to clean the wall from the old coating. But this is a rather dusty method, so plaster must be constantly moistened. You can clean the wall with a spatula, but on condition that the coating is loose and not very strong. This is a rather laborious process, requiring considerable effort and time. Therefore, the masters advise to use it only as a last resort. Given the recommendations outlined above, you can easily clean the walls of the plaster and cope with the task.
