From the garden-cities in the 1920s, via the high rise blocks in the post-war period, to the urban renewal in the 1970s, one of the great achievements of the 20thcentury is the concept and realisation of social housing. Nowadays however, the heritage value of these everyday dwelling spaces is contested and under threat. In order to align the on-going energetic renovation programme with heritage values, the Flanders Heritage Agency is -in collaboration with the Flemish Social Housing Company- carrying out a typologically based inventorisation of the social housing stock built before 1985. This assignment however, ultimately resulting in a policy- oriented evaluation, raises a lot of methodological questions ranging from substantive ones such as the relation between heritage and issues like uniformity, street patterns, or contemporary dwelling quality, to more practical ones such as the use of GIS- and online applications.