A one-part vehicle side wall and the method of its formation. On the longitudinal upper and lower edges of the wall there are formed from the material of the side wall an upper border and a lower border that during the assembly of the side walls complement each other in form. The upper strengthening border is provided with a concave formation into which the lower strengthening border fits and in which it is adjustable in steps. The method is characterized in that the side wall is made of a sheet steel strip by means of rolling on a rolling train in a single working pass in which there are partly formed the needed strengthening formations and partly also the bending of the strengthening borders into a final closed form.