A superstructure for a drain located in the floor area of a washing or showering area, which is to be installed in a wall element, comprising: - a cover box to be placed over the drain and having a rear wall, a top wall and side walls (18, 18'; 118, 118') connected thereto, wherein the cover box has an underside open towards the drain and a front side open towards the interior of the washing or showering area, for receiving a panel-shaped cover flap of the superstructure, - wherein the cover flap has a first visible surface pointing outwards in the direction, a second visible surface (24; 24') pointing inwards in the direction and a bottom edge and, when mounted, is aligned approximately perpendicular to a floor surface of the washing or showering area and arranged in such a manner that a drain slot remains below the bottom edge, - and wherein cover flap and cover box are detachably coupled to each other via a mounting of the superstructure and the cover flap is movable about an axis of rotation, - and wherein mutually compatible guide elements (31, 32; 131, 132) are provided on the side walls (18, 18'; 118, 118') of the cover box or on the cover flap, which guide elements (31, 32; 131, 132) are in each case arranged in a plane running perpendicular to the rear wall and/or top wall of the cover box and can be fixed to the cover box or to the cover flap by means of an adjusting element of the superstructure, - and wherein the mounting can be displaced via a first element of the guide elements (31; 131) in a direction perpendicular to the top wall and via a second element of the guide elements (32; 132) in a direction perpendicular to the rear wall, so that the position of the cover flap with respect to the cover box can be pre-defined both with respect to its distance from the top wall and with respect to its distance from the rear wall and can be fixed with the adjusting element, characterized in that the first guide element (31; 131) is a first guide carriage (41; 141) led along a U-shaped depression in the side wall (18, 18'; 118, 118') of the cover box, by means of which the position of the cover flap in relation to the cover box can be adjusted with respect to its distance from the top wall or to the rear wall. - a cover box to be placed over the drain and having a rear wall, a top wall and side walls (18, 18'; 118, 118') connected thereto, wherein the cover box has an underside open towards the drain and a front side open towards the interior of the washing or showering area, for receiving a panel-shaped cover flap of the superstructure, - wherein the cover flap has a first visible surface pointing outwards in the direction, a second visible surface (24; 24') pointing inwards in the direction and a bottom edge and, when mounted, is aligned approximately perpendicular to a floor surface of the washing or showering area and arranged in such a manner that a drain slot remains below the bottom edge, - and wherein cover flap and cover box are detachably coupled to each other via a mounting of the superstructure and the cover flap is movable about an axis of rotation, - and wherein mutually compatible guide elements (31, 32; 131, 132) are provided on the side walls (18, 18'; 118, 118') of the cover box or on the cover flap, which guide elements (31, 32; 131, 132) are in each case arranged in a plane running perpendicular to the rear wall and/or top wall of the cover box and can be fixed to the cover box or to the cover flap by means of an adjusting element of the superstructure, - and wherein the mounting can be displaced via a first element of the guide elements (31; 131) in a direction perpendicular to the top wall and via a second element of the guide elements (32; 132) in a direction perpendicular to the rear wall, so that the position of the cover flap with respect to the cover box can be pre-defined both with respect to its distance from the top wall and with respect to its distance from the rear wall and can be fixed with the adjusting element,