A stair stringer includes a pair of joists each including an upper wall, a first lateral wall extending from the upper wall, and a second lateral wall extending from the upper wall. At least one stair step support bracket includes a tray support wall, a first side wall extending from the tray support wall, a second side wall extending from the tray support wall, and a front wall extending between the first side wall and the second side wall. The at least one stair step support bracket is configured to set on the upper wall of one of the pair of joists and the first side wall extending downward beyond the upper wall of the one joist in position to receive a first fastener through the first side wall and into the first lateral wall of the one joist, and the second side wall extending downward beyond the upper wall of the one joist in position to receive a second fastener through the second side wall and into the second lateral wall of the one joist, wherein the tray support wall is level.

A temporary tread insert and method for installation in a stairway framework during building construction. The temporary tread insert includes an insert body having an upper tread surface, a bottom surface and opposed side surfaces. A front end of the insert body has a substantially bullnose shaped curved surface. The upper tread surface has a notched surface extending along the upper tread surface. Also disclosed is the method of inserting the temporary tread insert into the stair pan of a stairway framework, where the stair pan includes a bullnose at a front end of the stair pan, and the bullnose has a portion extending laterally a distance into the stair pan. The temporary tread insert includes a notched surface. The method includes positioning the temporary tread insert above a bottom of the pan, inserting the notched end of the temporary tread insert beneath the laterally extending portion of the bullnose, and moving the rear end of the temporary tread insert downward until the notched end of the temporary tread insert engages the underside of the portion extending laterally from the bullnose.

A temporary tread insert and method for installation in a stairway framework during building construction. The temporary tread insert includes an insert body having an upper tread surface, a bottom surface and opposed side surfaces. A front end of the insert body has a substantially bullnose shaped curved surface. The upper tread surface has a notched surface extending along the upper tread surface. Also disclosed is the method of inserting the temporary tread insert into the stair pan of a stairway framework, where the stair pan includes a bullnose at a front end of the stair pan, and the bullnose has a portion extending laterally a distance into the stair pan. The temporary tread insert includes a notched surface. The method includes positioning the temporary tread insert above a bottom of the pan, inserting the notched end of the temporary tread insert beneath the laterally extending portion of the bullnose, and moving the rear end of the temporary tread insert downward until the notched end of the temporary tread insert engages the underside of the portion extending laterally from the bullnose.

A stair assembly includes at least one joist comprising an upper wall, a first lateral wall extending from the upper wall, and a second lateral wall extending from the upper wall. At least one stair step support bracket includes a tray support wall, a first side wall extending from the tray support wall, and a second side wall extending from the tray support wall. The first and second side walls define a pair of first front aligned positioning holes configured to receive a first set pin and a pair of first rear aligned positioning holes configured to receive a second set pin. The pairs of first front and rear aligned positioning holes disposed such that when the first and second set pins received therethrough contact the upper wall of the at least one joist, the tray support wall is positioned at a first rise dimension.

A method is disclosed of attaching a tread assembly of a spiral staircase to a vertical support column. One step of the method involves providing a tread assembly having a tread portion attached to an arcuate mounting plate defining at least one hole through which extends a fastener defining external threads, the mounting plate having a first face defining a first radius of curvature. Another step involves providing a support column extending along an axis, the support column having a plurality of axially and angularly spaced apart tread attachment locations, each of the tread attachment locations having an arcuate outer surface defining a corresponding aperture for receipt of the fastener, the arcuate outer surface defining a second radius of curvature that is greater than the first radius of curvature. According to another step of the method, the tread assembly is loosely connected to one of the tread attachment locations of the support column. According to another step, the fastener is tightened such that the arcuate mounting plate of the tread assembly is elastically deformed to be in substantial engagement with the tread attachment location and applies tension to the elongate fastener to inhibit loosening thereof.

A method is disclosed of attaching a tread assembly of a spiral staircase to a vertical support column. One step of the method involves providing a tread assembly having a tread portion attached to an arcuate mounting plate defining at least one hole through which extends a fastener defining external threads, the mounting plate having a first face defining a first radius of curvature. Another step involves providing a support column extending along an axis, the support column having a plurality of axially and angularly spaced apart tread attachment locations, each of the tread attachment locations having an arcuate outer surface defining a corresponding aperture for receipt of the fastener, the arcuate outer surface defining a second radius of curvature that is greater than the first radius of curvature. According to another step of the method, the tread assembly is loosely connected to one of the tread attachment locations of the support column. According to another step, the fastener is tightened such that the arcuate mounting plate of the tread assembly is elastically deformed to be in substantial engagement with the tread attachment location and applies tension to the elongate fastener to inhibit loosening thereof.

A modular platform system utilizing a number of components including a platform. The platform is configured so that each of the components may interchangeably connect to any side of the platform. The components include, for example, handrails and stairways, as well as other platforms. The platform and most of the components are formed from single, continuous pieces of metal.

A method for building modular stair system comprises assembling a plurality of modular stair units, each of the plurality of modular stair units associated with a single story of a construction, each of the plurality of modular stair units further comprising a self-supporting structure supported by a plurality of corner columns. A first modular stair unit is located on a foundation of a structure. The first modular stair unit is secured to the foundation of the structure. A second modular stair unit is stacked on top of the first modular stair unit, wherein a first plurality of corner support columns engage of the first modular stair unit engage a second plurality of corner support columns of the second modular stair unit. The second modular stair unit is leveled using a connection sleeve that slides within the first plurality of corner support columns and the second plurality of corner support columns. The second modular stair unit is connected to the first modular stair unit to maintain the leveled second modular stair unit using the connection sleeve.