Method of retrofitting a bathtub drainage pipe

A method of retrofitting a concrete-encased drainage pipe adapted for a bathtub drain for use with a shower drain, comprising the steps of:

• removing a pre-existing bathtub drain to expose the concrete-encased drainage pipe without digging into the concrete encasing the drainage pipe;
• frictionally attaching a rubber gasket to an exposed end of said concrete-encased drainage pipe;
• and
• attaching a drain body adapted for shower use to said rubber gasket;
• threadably engaging a separate fastener with said drain body and said rubber gasket to interconnect said drain body and said rubber gasket to each other;
• wherein a top-most edge of said drain body comprises a radial flange;
• wherein said radial flange is of a width which is twice as large as a longest distance of said drain body which is perpendicular to a diameter of said radial flange.

A retrofit drain adaptor adapted for shower use, said drain adaptor comprising:

• a gasket;
• a radial flange;
• a drain body including a first end, a tapered second end, and a threaded borehole extending longitudinally through the borehole between the first end and the tapered second end, said drain body having a top-most edge which forms a unitary structure with said radial flange;
• a strainer, said strainer fixedly attached to said top-most edge of said drain body and placed concentrically within an area circumscribed by an outermost edge of said radial flange,
• wherein said gasket is sized to fit circumferentially around a drainage pipe and to slide partially through said drain body from above.