Returned stair tread having moisture compensating joint and method for making the same

A method for making a returned stair tread assembly for use on an open stairway or an open portion of a stairway, the method comprising the steps of:

• providing a stair tread plate having a front edge surface and a side edge surface;
• providing a front nosing having a front edge surface, a rear edge surface and a side edge surface, the front nosing having a rear groove formed along the rear edge surface of the front nosing;
• providing a return nosing having a side groove formed along only a portion of an inner surface of the return nosing, a front end of the side groove spaced from a forward end of the return nosing, the side groove having a forward portion formed in a front portion of the inner surface of the return nosing and a rearward portion formed in a rear portion of the inner surface of the return nosing;
• forming a side tongue along the side edge surface of the stair tread plate and a front nosing tongue along only a portion of the front nosing so that the front nosing tongue is spaced from forward and rearward ends of the side edge surface of the front nosing;
• attaching the front nosing to the stair tread plate so that the rear edge surface of the front nosing engages the front edge surface of the stair tread plate;
• and
• mounting the return nosing to the front nosing and the stair tread plate by inserting the front nosing tongue into the forward portion of the side groove of the return nosing and the side tongue of the stair tread plate into the rearward portion of the side groove to form an exposed joint between the side edge surface of the front nosing and the front portion of the inner surface of the return nosing, the side tongue of the stair tread plate and the rearward portion of the side groove of the return nosing slidably connected to one another along at least rear portions thereof rearward of the exposed joint.

A staircase, comprising a side stringer having a plurality of horizontal tread receiving surfaces and a plurality of returned tread assemblies, wherein each returned tread assembly comprises:

• a stair tread plate having a front edge surface and a side edge surface;
• a front nosing having a front edge surface, a rear edge surface and a side edge surface, the rear edge surface of the front nosing fitted engaging the side edge surface of the stair tread plate;
• and
• a return nosing engaging the side edge surfaces of the stair tread plate and the front nosing to form an exposed joint between the front nosing and the return nosing along the side edge surface of the front nosing and a front portion of the return nosing;
• a side tongue formed along the side edge surface of the stair tread plate;
• a front nosing tongue formed along a portion of the side edge surface of the front nosing spaced from forward and rearward ends of the side edge surface of the front nosing;
• a side groove extending along a portion of an inner surface of the return nosing and receiving the front nosing tongue of the front nosing and the side tongue of the stair tread plate;
• the front nosing tongue and the side tongue disposed in the side groove and slidably connect the stair tread plate and the return nosing along at least rear portions of the return nosing.