This thesis tries to describe the social, economic and political conditions in Graz during the second part of the 19th until the middle of the 20th century, as illustrated by its buildings regulations. These regulations not only reflect the living conditions, they also show the struggle between the legislative instruments and the citys political administration for the best solution. This thesis tries to describe the efforts of the persons responsible for a better law or new buildings regulations for this city, it deals with the question of political influence in a time, when the population grew three times, after the city territory changed its size, four times.Special attention was given to the basements flats and attic flats, lodges destined for socially disadvantaged people. Within the borders of the Habsburg Monarchy, the highest rate of this kind of poor flats could be met above all big cities in Graz.Beyond these specific aspects, the thesis shows further important details for the citys development, like authorized buildings heights, the dimensions of inner courtyards and problems of road regulations. It also shows the possibilities for construction departments, to request sides and work from investors for new or broader streets or even to expropriate them. The critical question is to what extent private property can be cut down on behalf of traffic needs for everybody. These questions had different answers every time. A temporary conclusion confirms the fact, that the heavy growth of cities in Middle Europe from the 19th Century until World War I did not lead in Graz to a massive building up of inner courtyards with a high number of backyard lodgings (?Hinterhauswohnungen?). Instead the immigrants often shifted to basement flats or flats under the roof, the city authorities were aware of health problems, and for a longer time they expressed their antipathy against it.