The renovation of the housing project from 1967 on the Siersteenlaan in Groningen demonstrates that in an integrated approach a wide range of objectives to improve existing buildings can be reached. In this project the goals were the improvement of the urban situation, the architectural appearance, the social control, diversification of dwelling types and a higher functional quality. The solution of the problems was specifically adapted to the existing ‘Rottinghuis’ building system. Large one- and two-floor apartments were created on the ground floor, and the accessibility of the remaining smaller apartments on the upper floors was improved by adding elevators. With diverse additions to the existing buildings different problems were solved. By making as little changes to the structure as possible, the intention to develop more diversification was reached at acceptable cost.