Abstract: A sheeting device includes a column with two supporting surfaces in one guide channel. The second supporting surface is provided with an offset relative to the first supporting surface. The offset is both toward the middle of the column in the lengthwise direction of the trench and also in the transverse direction toward the wall of the trench, with one edge of an outer plate of the sheeting device abutting this second supporting surface. As a result of the two supporting surfaces that are offset with respect to one another in the lengthwise and transverse directions of the trench, the guide channel offers each of the plates support in extension of the lengthwise extent of the respective plate. Two inwardly projecting supporting edges on the outer plates are dispensable. Eliminating these supporting edges has the additional advantage that the stacked volume of the outer plates is reduced by approximately half.