A self-supporting wood panel system for a building comprising: - a plurality of self-supporting wall panels of engineered wood and adapted to support the building and; - at least one self-supporting transverse panel of engineered wood,wherein, each of the plurality of wall panels and each of the at least one transverse panel comprise two main surfaces (11,31) and a plurality of side surfaces (12,32), and the at least one transverse panel is adapted to rest upon at least two wall panels, and thereby forming a roof and/or floor of the building, and the plurality of wall panels are connectable at their side surfaces to the at least one transverse panel by a plurality of dovetail joints, whereby the dovetail joints are configured to fasten the transverse panel to at least two wall panels to secure the transverse panel to the wall panels in the extension directions of the transverse panels main surfaces, and characterized in that the system further comprising first dowels, and the plurality of wall panels comprises first dowel openings aligned with the extension of their main surfaces and arranged at the side surface of the wall panels comprising the dovetail joints and in between the dovetail joints, and the plurality of wall panels comprises corresponding first dowel openings arranged on an opposite side surface of the wall panels and aligned with the extension of their main surfaces such that the first dowels can be arranged in the respective first dowel openings to protrude inside the corresponding first dowel opening in a first wall panel and in a corresponding first dowel opening in a second wall panel arranged thereupon. - a plurality of self-supporting wall panels of engineered wood and adapted to support the building and; - at least one self-supporting transverse panel of engineered wood,wherein, each of the plurality of wall panels and each of the at least one transverse panel comprise two main surfaces (11,31) and a plurality of side surfaces (12,32), and the at least one transverse panel is adapted to rest upon at least two wall panels, and thereby forming a roof and/or floor of the building, and the plurality of wall panels are connectable at their side surfaces to the at least one transverse panel by a plurality of dovetail joints, whereby the dovetail joints are configured to fasten the transverse panel to at least two wall panels to secure the transverse panel to the wall panels in the extension directions of the transverse panels main surfaces, and characterized in that the system further comprising first dowels, and the plurality of wall panels comprises first dowel openings aligned with the extension of their main surfaces and arranged at the side surface of the wall panels comprising the dovetail joints and in between the dovetail joints, and the plurality of wall panels comprises corresponding first dowel openings arranged on an opposite side surface of the wall panels and aligned with the extension of their main surfaces such that the first dowels can be arranged in the respective first dowel openings to protrude inside the corresponding first dowel opening in a first wall panel and in a corresponding first dowel opening in a second wall panel arranged thereupon.