The interfloor overlap is done with beams and reinforced concrete slabs, roof insulation is 200/250mm. Architecture varies from simple to complex, often panoramic windows, ”second light” or roof skylights are used. A full second floor provides more opportunities in terms of organization and living space.  The price form one sq.m. is lower than for a standard one-story house, due to the common foundation for both floors and the roof, with a smaller area. This kind of house is commonly used to save land area in densely built areas.