Abstract: To exclude odors, drafts, insects and rodents from the necessary opening in a bathroom floor surrounding the tub drain, an open top dry enclosure box for the tub drain is placed in the floor opening in surrounding relationship to the drain components and includes an upper three-sided narrow suspension flange resting on the top floor surface. The enclosure box is provided in three of its side walls and its bottom wall with knock-out discs to provide a passageway through the enclosure box for either a horizontal or vertical drain pipe downstream from the drain trap, thereby rendering the drain box universal in its application to tub drains.

Abstract: A prefabricated metallic open top box with attached top flanges and bottom wall threaded nipple surrounds the tub drain components and excludes insects and mice from the space beneath the tub. Odors are also excluded from this area by the enclosure. The threaded nipple is readily coupled to the tub drain and descending pipe. The use of the enclosure eliminates the need for constructing a form around the tub drain prior to pouring the concrete floor.