It is disclosed a building element (24) for a floor construction and/or roof construction in a building (10), which building element comprises an upper side (25), a lower side (26), at least one first lateral face (27), and at least one first end face (28), wherein the at least one lateral face is formed with a longitudinal lateral groove (30) such that a longitudinal upper grove edge (32) and a longitudinal lower groove edge (31) are formed, which upper groove edge has a toothed shape. Also disclosed is a building (10) comprising one or more load bearing elements (12), and a plurality of building elements (24) connected to respective load bearing elements, and a method of joining building elements and load bearing elements in a building.