This paper will investigate how an existing office building can be transformed into a residential building in a demountable way. Firstly, an overview will be provided of existing demountability quantification methods. Secondly, a case study will be presented with connection details of an office building; De Knip in Amsterdam Sloterdijk, a building that is initially not designed to be demountable. The case study will be analyzed by two existing demountability quantification tools. Finally, the relation between demountability and the functional change from an office- to a residential building will be investigated on the basis of technical and architectural aspects (appendix 5a,b,c). In this paper the quantification of the demountable components of the building skin- & load bearing structure will be the focus points.