Wohnbaugenossenschaft Siedlungsunion is a non-profit housing cooperative based in Vienna, Austria, with its headquarters at Mergenthalerplatz 10, in the 22nd district. The organization operates as a limited-profit entity under Austrian law, focusing on the development, management, and rental of residential and mixed-use properties primarily in and around Vienna.
Siedlungsunion’s origins trace back to the early 1920s, a period marked by severe housing shortages in Vienna. The cooperative was established to address the pressing need for affordable and quality housing during the rapid urban expansion following World War I. As a member of Austria’s sector of gemeinnützige Bauvereinigungen (non-profit housing associations), Siedlungsunion is embedded in a tradition of communal housing efforts, which have significantly shaped Vienna’s social housing landscape.
The organization’s portfolio includes a wide spectrum of projects from traditional multi-family dwellings to modern mixed-use developments. A recent project celebrated its topping-out ceremony in September 2025 on Tamariskengasse 43/Wulzendorfstraße 32 in the 22nd district of Vienna. Another notable collaboration is the “Fünf Freund*innen” social housing project, realized with architectural partnerships and supported by public housing initiatives.
Siedlungsunion’s core activities span from property development and construction management to long-term maintenance and tenant support. The cooperative is distinguished by its aim for durable housing quality, financial sustainability, and stable tenancy arrangements, directly managing the dwellings it builds. Its ongoing projects continue to contribute to Vienna’s extensive social and cooperative housing stock.