A spiral staircase comprises a mounting column extending along a longitudinal axis. A plurality of tread assemblies each having a tread portion attached to a mounting plate is also provided. The tread assemblies are axially and angularly offset from an adjacent tread assemblies along the mounting column. In this aspect, each mounting plate has a first face that engages a corresponding portion of an outer surface of the mounting column and a second face from which the tread portion extends. Each of the tread assemblies further have attachment hardware that secures the mounting plate to the mounting column. Prior to attachment to the mounting column and in an unstressed state, the mounting plate has a first radius of curvature and the corresponding portion of the outer surface of the mounting column has a second radius of curvature. The first radius of curvature is less than the second radius of curvature so that when the mounting plate is secured to the column with the attachment hardware and the second face of the mounting plate substantially engages the mounting column, the mounting plate is in an elastically deformed state applying tension to the attachment hardware 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 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 ceiling ladder having a plurality of sections that can be climbed by a user when in an unfolded position into an attic and that can be folded together into a retracted position to be stored above the ceiling. The ladder has a deep step, which has a width greater than the width of other steps of the ladder, in which is located between about 2-5 feet from the floor when the ladder is in the unfolded position so user can stand on the deep step in place objects into the attic without having to climb into the attic. A method. A deep step.

An open staircase is provided comprising a flight of stair treads and an uncut stringer. The treads have free opposing ends positioned on the stringer in a stepped apart relationship relative to one another and each are fixed to the uncut stringer at a position along the horizontal length of the tread such that the tread is cantilevered from the stringer.

An open staircase is provided comprising a flight of stair treads and an uncut stringer. The treads have free opposing ends positioned on the stringer in a stepped apart relationship relative to one another and each are fixed to the uncut stringer at a position along the horizontal length of the tread such that the tread is cantilevered from the stringer.

A ceiling ladder having a plurality of sections that can be climbed by a user when in an unfolded position into an attic and that can be folded together into a retracted position to be stored above the ceiling. The ladder has a deep step, which has a width greater than the width of other steps of the ladder, in which is located between about 2-5 feet from the floor when the ladder is in the unfolded position so that a user can stand on the deep step and place objects into the attic without having to climb into the attic.

A ceiling ladder having a plurality of sections that can be climbed by a user when in an unfolded position into an attic and that can be folded together into a retracted position to be stored above the ceiling. The ladder has a deep step, which has a width greater than the width of other steps of the ladder, in which is located between about 2-5 feet from the floor when the ladder is in the unfolded position so that a user can stand on the deep step and place objects into the attic without having to climb into the attic.

A stair system according to one illustrative embodiment comprises: a support body mountable in a wall and comprising a connecting region; a stair body; and a mounting apparatus. The mounting apparatus comprises: a connector connectable to the connecting region of the support body in any one of a plurality of different positions in the connecting region of the support body; and a holder configured to hold the stair body such that when the connector is connected to the connecting region of the support body, the stair body is spaced apart from the support body to permit a wall panel between the stair body and the support body. Wall assemblies comprising such stair systems are also disclosed.

A stair system according to one illustrative embodiment comprises: a support body mountable in a wall and comprising a connecting region; a stair body; and a mounting apparatus. The mounting apparatus comprises: a connector connectable to the connecting region of the support body in any one of a plurality of different positions in the connecting region of the support body; and a holder configured to hold the stair body such that when the connector is connected to the connecting region of the support body, the stair body is spaced apart from the support body to permit a wall panel between the stair body and the support body. Wall assemblies comprising such stair systems are also disclosed.