A stair box system made of a stair box core, stringers, risers and treads. The inner surfaces of the stringers have a discontinuous series of mortises positioned to engage only with the treads. Each tread is beveled from the front to back surfaces and each of the riser is beveled from the top to the bottom surface. Each tread features one or more notches cut into its back surface and each riser includes a complementary hook cut into its bottom surface. The hooks on the risers engage the notches on the treads forming an open-faced channel. Removable covers fit over the treads of the stair box core. These covers protect the stair box core and/or they feature decorative building materials like hardwood or tile. The system allows the user to upgrade their stairs by replacing the covers with covers featuring a different finished surface.

A stair box system made of a stair box core, stringers, risers and treads. The inner surfaces of the stringers have a discontinuous series of mortises positioned to engage only with the treads. Each tread is beveled from the front to back surfaces and each of the riser is beveled from the top to the bottom surface. Each tread features one or more notches cut into its back surface and each riser includes a complementary hook cut into its bottom surface. The hooks on the risers engage the notches on the treads forming an open-faced channel. Removable covers fit over the treads of the stair box core. These covers protect the stair box core and/or they feature decorative building materials like hardwood or tile. The system allows the user to upgrade their stairs by replacing the covers with covers featuring a different finished surface.

A stair box system made of a stair box core, stringers, risers and treads. The inner surfaces of the stringers have a discontinuous series of mortises positioned to engage only with the treads. Each tread is beveled from the front to back surfaces and each of the riser is beveled from the top to the bottom surface. Each tread features one or more notches cut into its back surface and each riser includes a complementary hook cut into its bottom surface. The hooks on the risers engage the notches on the treads forming an open-faced channel. Removable covers fit over the treads of the stair box core. These covers protect the stair box core and/or they feature decorative building materials like hardwood or tile. The system allows the user to upgrade their stairs by replacing the covers with covers featuring a different finished surface.

A stair box system made of a stair box core, stringers, risers and treads. The inner surfaces of the stringers have a discontinuous series of mortises positioned to engage only with the treads. Each tread is beveled from the front to back surfaces and each of the riser is beveled from the top to the bottom surface. Each tread features one or more notches cut into its back surface and each riser includes a complementary hook cut into its bottom surface. The hooks on the risers engage the notches on the treads forming an open-faced channel. Removable covers fit over the treads of the stair box core. These covers protect the stair box core and/or they feature decorative building materials like hardwood or tile. The system allows the user to upgrade their stairs by replacing the covers with covers featuring a different finished surface.

The step for modular staircases comprises a portion of tread (2) associated with a support body (3) suitable for permitting the reciprocal assembly of the adjacent steps (1). The support body (3) comprises a pair of beams extending substantially vertically, suitable for being arranged facing one another in mounting position so as to define respective sides (40) of the step (1). Protruding perpendicular from the sides (40) are a respective upper bracket (5) and a respective lower bracket (6), suitable one for supporting in support said portion of tread (2) and the other for being secured to an opposite bracket (5) of an adjacent step (1).

The step for modular staircases comprises a portion of tread (2) associated with a support body (3) suitable for permitting the reciprocal assembly of the adjacent steps (1). The support body (3) comprises a pair of beams extending substantially vertically, suitable for being arranged facing one another in mounting position so as to define respective sides (40) of the step (1). Protruding perpendicular from the sides (40) are a respective upper bracket (5) and a respective lower bracket (6), suitable one for supporting in support said portion of tread (2) and the other for being secured to an opposite bracket (5) of an adjacent step (1).

A curved pathway including a double helix form with no center support column includes a plurality of segments, wherein each of the segments is formed from a plurality of rods coupled to a plurality of connecting nodes. The plurality of rods are arranged in a skewed tetrahedral geometry, which causes the plurality of stair segments to form a helical structure when the plurality of segments are coupled together. The plurality of rods form a spine on an underside of the plurality of stair segments. A pathway surface is coupled to each of the segments. In alternate embodiments, the curved pathway may be formed from sheet metal creased to form a plurality of linear support locations and connecting nodes.

A curved pathway including a double helix form with no center support column includes a plurality of segments, wherein each of the segments is formed from a plurality of rods coupled to a plurality of connecting nodes. The plurality of rods are arranged in a skewed tetrahedral geometry, which causes the plurality of stair segments to form a helical structure when the plurality of segments are coupled together. The plurality of rods form a spine on an underside of the plurality of stair segments. A pathway surface is coupled to each of the segments. In alternate embodiments, the curved pathway may be formed from sheet metal creased to form a plurality of linear support locations and connecting nodes.

A pre-cast concrete stair tread is provided where the stair tread has reinforced corrugated metal embedded within the core of the concrete stair tread. The corrugations are lined up along the elongated direction of the stair tread. Concrete is poured and cured over at least one side of the corrugated metal. Additionally, the pre-cast concrete stair tread may have one or more metal straps fixed on the reinforced corrugated metal in a direction perpendicular to the corrugations and the elongated direction.

A pre-cast concrete stair tread is provided where the stair tread has reinforced corrugated metal embedded within the core of the concrete stair tread. The corrugations are lined up along the elongated direction of the stair tread. Concrete is poured and cured over at least one side of the corrugated metal. Additionally, the pre-cast concrete stair tread may have one or more metal straps fixed on the reinforced corrugated metal in a direction perpendicular to the corrugations and the elongated direction.