During an inventory of Ör church’s roof structure in 2021, it was discovered that the roofstructure above the church’s nave contains a large amount of reused structural parts froman earlier roof structure. The reused structural parts are most likely originated from Örchurch’s early medieval roof structure.This thesis is an attempt to reconstruct the early medieval roof structure with the use of3D-laser scanning. The goal is to present a possible shape and 3D-model of the earlymedieval roof structure. The existing roof structure will also be documented. One aim ofthe thesis is to develop and evaluate the method of using 3D-laser scanning for thispurpose.The reconstruction resulted in eight different shapes and 3D-models of the early medievalroof structure. The documentation of the existing roof structure above the nave resulted inupdated section, plan and detailed drawings.The method of using 3D-laser scanning gave a detailed point cloud of the existing roofstructure. The point cloud had low density points in certain parts of the roof structurewhich is a consequence from the implementation of the 3D laser scanning. For thismethod a field study and planning in advance is recommended for best possible result.