Office vacancy is an ever dominant problem in the Netherlands and abroad. While there are still a lot of issues unresolved, we might be overwhelmed with ideas, concepts and suggestions on how to tackle this vacancy. This graduation project tried to give a different perspective on this vacancy by introducing the concept of OPEN BUILDING and link this phenomenon with the mid-income housing shortage situation. The project will stress the problem with a design strategy in steps. In the first initiative part, the architect will work together with the developer or housing company to assess the transformation possibility to find a matching target vacant office building. The target building’s location characteristics and physical building characteristics will be assessed.