Preparation for wall repair always begins with the fact that the old coating is completely removed from them. If we are talking about houses of Soviet construction, then the ceiling was processed with special lime whitewashing at that time. Today more modern times, and use for these purposes to paint water-dispersion. Rinse from the ceiling surface just such a paint, as in principle, and other types of enamels cannot.To prepare the ceiling surface, more than enough such an event as removing all those areas that have been exfoliated very much, and you need to use a regular spatula for such work. In addition, the spatula is extended by cracks on the ceiling if you have them. After this, the surface of the ceiling is treated with the most ordinary sandpaper — that is, in this way we remove the maximum possible enamel. All this is necessary solely in order to most enhance the roughness, and thereby improve the adhesion to the material that you will apply. A special plasterboard ceiling will save you from such troubles, because in installation and further maintenance it is maximum simple.
In the event that the ceiling is covered with lime, then it is washed off until there is only a layer of putty on the surface of the ceiling. This process is not at all difficult, but as you know, it is quite long. So, the better you do all these works, the much better and much better with the base will clarify the new coating.
To completely wash off the whitewash layer, you need to moisten the entire ceiling by the most thoroughly with water and therefore simply carefully remove it with a spatula. You will not be able to completely and everywhere get rid of the whitewash system, and therefore such actions are repeated until then until the ceiling is in the form in which we need it. All the remnants of the lime whitewashing, which will be, should be washed as thoroughly from the ceiling surface, and you need to use a wet sponge for this.