A method of manufacturing a customized shower pan or floor includes the steps in which the desired shower stall area is measured to determine an outer periphery with regard to the existing drain in situ and then a shower pan mold is constructed with both an outer and a drain periphery. In a first embodiment, a resin/filler is poured partway in to the mold and then pre-cut tiles are placed in a desired manner on top of the resin while it cures. In a second embodiment, a single slab is poured with a resin/filler mixed with crushed or powdered stone, metal, or the like. The set shower pan is then placed and the drain periphery is grouted to the existing drain and plumbed.