Abstract: A device in which wall elements are jointed together by corner joints to form house walls, partitions, frames, boxes, etc. The wall elements are formed identical, and the wall elements (1,2, FIG. 9) preferably at both ends having a recess determined by an edge surface of the wall element and a projection. The projection, in the transverse direction of the wall element, has the same width as the length of the edge surface. The projections have two sides. One side is provided with a guide groove extending in the transverse direction of the wall element for receiving an edge surface of another wall element. On the other side the projections are provided with a support groove also extending in the transverse direction of the wall element for engaging with a corner post.