Why not just have to face during the repair of the apartment. Perhaps the most trouble delivers incorporation of small shells in concrete structures: have a long “RUB” the putty into every crevice. However, this work can be greatly simplified. First, you need to dissolve the cement-sand mortar and apply it in a thin layer on a pre-moistened surface. Then, a piece of moistened foam, remove excess cement them. After drying, the solution plane will be smooth without any cracks and sinks.