Stairway tread and riser assembly

A method for assembling a stairway comprising:

• providing a one-piece, unitary gusset having an upper surface, a lower surface, an integral tread attachment structure, an integral riser attachment structure and a line of weakening between the tread attachment structure and the riser attachment structure, the line of weakening enabling bending of the gusset between a flat position and a bent position;
• providing a tread panel having an upper surface, a lower surface and a side edge, the tread panel defining a tread thickness between said upper surface and said lower surface;
• providing a riser panel having an upper surface, a lower surface and a side edge;
• positioning the tread panel at a predetermined position with respect to the tread attachment structure;
• positioning a riser panel at a predetermined position with respect to the riser attachment structure and at a predetermined spacing from the tread panel, wherein the predetermined spacing is greater than the tread thickness;
• attaching the tread panel to the gusset at the predetermined location with the tread attachment structure by pressing the tread attachment structure into the tread panel with the gusset in the flat position;
• attaching the riser panel to the gusset at the predetermined location with the riser attachment structure by pressing the riser attachment structure into the riser panel with the gusset in the flat position;
• bending the gusset into the bent position with the tread panel and the riser panel attached to the gusset at the predetermined spacing, into a position in which the side edge of the riser panel overlaps and faces the upper surface of the tread panel and a portion of the gusset between the line of weakening and the riser attachment structure overlies a side edge of the tread panel, wherein the upper surface of the tread panel is perpendicular to the upper surface of the riser panel.