This paper presents the identified obstacles, needs and selected solutions for the study of the medieval castle of Franchimont, located in the province of Liège (Belgium). After taking into account the requirements from all the disciplines at work as well as the problems that would have to be tackled, the creation of a 3D point cloud was decided. This solution would be able to deal with the characteristics and needs of a research involving building archaeology and related fields. The decision was made in order to manage all of the available data and to provide a common working tool for every involved cultural heritage actor. To achieve this, the elaboration of an Archaeological Information System based on 3D point clouds as a common virtual workspace is being taken into consideration.

The major aim of my research is the application of tree-ring dating to the study of medieval and postmedieval buildings. An oak master chronology has been constructed for the period running from AD 672 to AD 1991 from 348 individual tree-ring series taken from buildings in the Meuse Basin, southeast Belgium. This sequence is useful for dating buildings in northern France or Holland that contain wood imported from Ardennes. Other oak chronologies are in preparation for northern France and northern Belgium. Tree-ring analysis for the study of roof-framing can provide dates of high precision when archives are not available. It then becomes possible to reconstruct the technical evolution of roof-framing between ca. 1000 and ca. 1800. I have identified some critical transitional periods: the influence of Gothic architecture ca. 1200-1250; the disappearance of common rafter roofs ca. 1490-1530 and the use of shorter and shorter timbers, or wood of poor quality, during the 17th and 18th centuries. Most of these changes are a consequence of deforestation, which is also identified in the tree-rings.