The interwar period was marked by a progressive urbanisation of the city of Belgrade and considerable residential construction works, which nevertheless could not respond to the high demand for housing caused by the rapid population growth. Large, luxurious apartments were built in buildings made of solid material, as well as small, courtyard flats in dilapidated houses intended for the poor working class. The paper explores construction achievements and techniques applied in the residential architecture of Belgrade during the interwar period, focusing on solid buildings that make up the housing stock of the city even to this day. From the perspective of the civil engineering development, the period between the two world wars saw the continual usage of massive structures and bricks as dominant masonry material, while the greatest number of changes and innovative solutions could be seen in the construction of floors, the development of which represented a significant breakthrough regarding the construction elements used in residential buildings. The novelty was a greater usage of reinforced concrete that was predominantly used for the construction of floors and foundations, while bricks remained the only wall-building material. That period saw a significant improvement of the technical legislation, primarily through the adoption of the 1931 Construction Law. The paper is part of a more comprehensive research covering a wider period of time that looks into the construction techniques applied in the residential architecture of Belgrade, and which was conducted for the purpose of setting up the typology of construction assembly elements with the general view to valorising the comfort in Belgrade residential buildings.