Abstract: Edge rails for a mattress core are combined with an upholstery layer to provide a pre-assembled work piece that provides a perimeter about a mattress core. The edge rails, which may be foam, may be attached to the upholstery layer with hinges that permit each edge rail to rotate relative to the upholstery layer between an unassembled, flat position and an assembled, upright position. In the unassembled position, the work piece may present a relatively flat profile for more convenient bulk storage. In the assembled position, the edge rails are positioned to closely surround a mattress core of suitable size.