Abstract: Floor drainage systems in locations using a relatively large amount of water are usually covered with expanded metal gratings which easily become blocked and do not allow sufficient support for relatively heavy vehicular traffic to pass thereover. The present device utilizes a culvert section having spaced apart upper angle members and a sheetmetal culvert depending there below, the depth of which gradually increases from one end to the other. Location tabs extend from the sides of the culvert along the length thereof and these are all spaced the same distance downwardly from the upper angle members so that the sections are all readily supported upon pegs placed along the trench at the same depth from the surface. Concrete may then be poured around and under the culvert and the floor surface finished flush with the upper surface of the angle members so that only an elongated slot is seen when the installation is completed.