The special value that is attributed to historic buildings and structures is the foundation of built heritage conservation and preservation. National guidelines and international charters state that the cultural-historical values attributed to a monument must be leading in drawing up and assessing preservation plans for a monument. To indicate the values, an art-, architectural-, cultural-historical or building archaeological research is carried out and a value assessment is drawn up. Recent social-cultural, political, economic and scientific developments, in and outside the field of conservation, call for a new organization and multidisciplinary approach of conservation and preservation and for an adjustment of the notion of value and the process of valuation. This research presents a description and analysis of the emergence and development of value assessment and of the part a value assessment plays in drawing up and assessing preservation plans. This gives insight in the requirements for a value assessment, in terms of content and process, that result from the recent changes in conservation and preservation theory and practice. The conceptual approach of ‘values-centered preservation’ in combination with the approach developed within the field of art conservation, offers interesting points of departure for a new set-up for value assessment. A combination of literature studies and a multiple case study led to the development of a model for a customized manner for value assessment. This model encourages to broaden the scope of value assessment and to transcend disciplinary boundaries, thus supporting a multidisciplinary approach for built heritage conservation and preservation.