The difference in the quality and behavior of historical and contemporary trusses, inter alia, particularly in the way of cutting timber and making a selection for a specific location in the truss structure. Current truss construction - now prevailing truss systems are extremely sensitive to the position of grained structure in the beam. If the different beam behaviour with various ring positions is not accepted, then it leads to the deformation of individual elements and then to the deformation of the whole roof.