The builders of the Berlin Garden towns and large housing estates found the land they needed for implementing the housing policy at the quality needed in the rural outer districts of Berlin. The intense development in that part of the city required the existence of the city itself with its economy and strong infrastructure. The new housing estates were situated near the stations of the tightly knit, expanding Berlin commuter transport network. All nominated estates were built by cooperatives and nonprofit organisations. Closed tenements with densely packed structures were replaced by the concept of open housing, created as garden towns and cities. This new concept represents a radical break from urban development of the 19th century with its corridor-like streets and reserved spaces for squares.
The effect of World War I on social policy and the founding of the Weimar republic had a great impact on the development of the city of Berlin. For the urban development plan the transition to the republic in 1918/19 brought a major change to working conditions. The democratic electoral law for regional and local parliaments opened the way to a more socially focussed development and planning policy. The new order also made it possible to implement long overdue changes in the administrative structure. This created the precondition for applying uniform planning principles to the entire area. The economic expansion of Berlin, mainly through electrical engineering, supported by municipal investment, facilitated Berlin's rise to the rank of an acknowledged metropolis. Planning works were dominated by the Berlin central government. The guidelines for housing policy and urban development were mainly determined by two urban councillors: Ludwig Hoffman and Martin Wagner. Wagner was a social democrat and architect, who pushed for the construction of reformed housing estates. This was most significant as the lack of housing in Berlin had been further aggravated by war. The political and economic consequence of World War I, in conjunction with the new building laws of the Weimar Republic, ended entirely private housing construction. The demand for small flats was from 100,000 to 130,000 units. Housing construction was finally re-activated, after inflation and currency reform, by the introduction of a mortgage servicing tax in 1924.
The reform building regulation, which became effective in 1925, provided the basis for new social housing. It aimed to reduce the density of buildings in residential estates and to separate the functions of individual zones. It divided the entire area of the city into different development zones - starting in the city centre where buildings were allowed 5 storeys in density, it decreased towards the outskirts where larger housing estates were built. Here buildings were allowed to reach a maximum of two to three storeys. The density of buildings was much reduced in these areas, where cross buildings and wings were prohibited. Berlin now had the opportunity to implement housing development in accordance with the models of neues bauen. Within only seven years (1924-1931) more than 146,000 flats were built. Such volume of construction was never again reached, not even during the post-war period of the 1950s. Wagner played a central role in non-profit housing welfare in Berlin during the Weimar Republic. For the development of the city he created a polycentric model, dissolving the division between town and countryside. Inside the railway ring, which surrounded the dense Berlin inner-city area, residential quarters were built of open multi-storey design within greenery, to fill the remaining gaps within the city's structure.
During the early phase of the mortgage servicing tax era, the main focus of housing policy was on developing estates of small single-family houses in suburban areas. By this means the responsible politicians wished to counteract the effect of proletarian mass housing and to re-create the people's link with houses and nature, which had been lost. They also wished to give the inhabitants of these housing estates the opportunity of self-sufficient food production. When the income from mortgage servicing tax decreased in the late 1920s, the city of Berlin mobilised its own finance to alleviate the still pressing shortage of housing with further estates built in multi-storey ribbon form. Although the economic crises of 1928-29 had an impact on housing construction, the Berlin government was still able to erect two large estates on the city own-land in 1929-31. When the Nazis took power in 1933, the structures of organisation and personnel in the municipal administration of Berlin completely changed and ended the democratic housing development, which was largely influenced by social-democracy, left-wing trade unions and cooperatives. Martin Wagner had to resign from office. The Nazis' building policy was based on a different idea of the arts. Modernity and neues bauen were no longer sought. Bruno Taut, Martin Wagner, Walter Gropius and many other authors of modern housing had to emigrate.
In the 1930s and 1940s, no major changes were made to the housing estates and they suffered very little destruction during the war. Their appearance was occasionally altered by early repair works after the war, when in some cases the works did not re-establish the original design. From the 1980s, many of these changes were replaced by new works re-establishing the original monuments. Refurbishment and modernisation programmes were introduced from the 1950s to maintain the basic fabric of the housing estates of Britz, Schillerpark, Weisse Stadt and Siemensstadt in West Berlin. These programmes did not take into account the principles of restoration and conservation. In the estates on East Berlin territory (Gartenstadt Falkenberg and Wohnstadt Carl Legien) only occasional repair works were carried out. In the western part of the city thorough restoration works began in the 1980s. These works were carried out in close cooperation among authorities, conservation experts, resident communities and the architects hired for the project. This process began in the eastern parts of the city in the 1990s after the reunification of Germany.