And first it must be scraped off with a sharp object to the main layer, if the plaster lies firmly, then you can put a patch on the damaged place, on the upper finishing layer. Before this, the surface must be cleaned and a binder is applied to it, in this case, PVA glue is taken. And apply it so that it captures the damaged place, when the glue layer dries, you can apply the finishing layer of plaster. At leisure it will not be superfluous to find out about the site .
