If the balcony is warm, then the floor must be equipped in the form of a sandwich. The lower layer should be laid slabs from insulation material, most often from polyurethane foam. Then a series of bricks on a cement mortar is laid, and a cement screed is already made on it, you can also use silicate brick. This screed will act as the basis for the system warm floor. And already this system is covered with flooring, for example, tiles, tiles, laminate, etc. D.