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 returned stair tread assembly comprises a tread plate, a front nosing and a return nosing fitted flush against each other to form an exposed joint between the front and return nosings, and a device for securing the return nosing to the front nosing and the stair tread plate. The tread plate has a side tongue. The front nosing has a front nosing tongue spaced from a forward end of a side edge surface of the front nosing. The return nosing receiving the front nosing tongue of the front nosing and the side tongue of the stair tread plate therein. A front end of the side groove is spaced from a forward end of the return nosing. The front nosing tongue and the side tongue are disposed in the side groove and configured to slidably connect the stair tread plate and the return nosing.

A returned stair tread assembly comprises a tread plate, a front nosing and a return nosing fitted flush against each other to form an exposed joint between the front and return nosings, and a device for securing the return nosing to the front nosing and the stair tread plate. The tread plate has a side tongue. The front nosing has a front nosing tongue spaced from a forward end of a side edge surface of the front nosing. The return nosing receiving the front nosing tongue of the front nosing and the side tongue of the stair tread plate therein. A front end of the side groove is spaced from a forward end of the return nosing. The front nosing tongue and the side tongue are disposed in the side groove and configured to slidably connect the stair tread plate and the return nosing.

Surface laying unit (100) for laying with other surface laying units (100) on an underlying surface (300), wherein the surface laying unit (100) has a useful layer (102) and a connecting structure (104) which is provided directly on an underside of the useful layer (102) and which is designed for connecting to the underlying surface (300).

Surface laying unit (100) for laying with other surface laying units (100) on an underlying surface (300), wherein the surface laying unit (100) has a useful layer (102) and a connecting structure (104) which is provided directly on an underside of the useful layer (102) and which is designed for connecting to the underlying surface (300).

A tread for a steel-pan staircase. The tread includes a lattice structure comprising a top side, a left side, and a right side. The tread further includes a top surface integrally formed on the top side of the lattice structure, a first tongue-and-groove structure disposed on the left side of the lattice structure, and a second tongue-and-groove structure disposed on the right side of the lattice structure. The lattice structure comprises a plurality of lateral members and a plurality of crosswise members. The first tongue-in-groove structure may include a wall descending from the top surface. The second tongue-in-groove structure may include a first wall extending outwardly from the right side of the lattice structure. Extending upwardly from the first wall may be a second wall or a plurality of teeth. The placement of the first and second tongue-in-groove structures may be reversed.

A tread for a steel-pan staircase. The tread includes a lattice structure comprising a top side, a left side, and a right side. The tread further includes a top surface integrally formed on the top side of the lattice structure, a first tongue-and-groove structure disposed on the left side of the lattice structure, and a second tongue-and-groove structure disposed on the right side of the lattice structure. The lattice structure comprises a plurality of lateral members and a plurality of crosswise members. The first tongue-in-groove structure may include a wall descending from the top surface. The second tongue-in-groove structure may include a first wall extending outwardly from the right side of the lattice structure. Extending upwardly from the first wall may be a second wall or a plurality of teeth. The placement of the first and second tongue-in-groove structures may be reversed.

A staircase kit, device, and method that uses precut, fixed-sized components capable of producing building code-compliant staircases that can accommodate foot or more differences in home story heights. The design uses fixed-length stringers and adjustable height risers. The angle between the stringers to the floor changes depending on the height of the adjustable height risers and story height. The angles of the steps, stringers and banisters/handrails are configured to adjust with respect to the other components with the aid of turnbuckles and movable joints or bolts, thus keeping the steps and landings level at different story heights. This enables homeowners, generally exempt from contractor license requirements, to use a prefabricated kit to build code-compliant stairways in their homes with little or no staircase cutting or part modification.

A device for making a molded stair tread is described. The device can have: a base; a pivoting assembly; a molding template connected to the pivoting assembly; a holding device connected to the molding template, the holding device having a clamp jaw and a pivot configured to rotate the holding device relative to the molding template; and a locking mechanism configured to hold the molding template and the holding device in an open configuration such that the holding device can accept a first part of the plastic sheet and configured to release the molding template and the holding device such that the holding device is in a securing configuration that secures, via the clamp jaw, the first part of the plastic sheet to the first side of the molding template at the first longitudinal edge of the molding template. Methods for making the stair tread are described as well as the molded stair tread.

A device for making a molded stair tread is described. The device can have: a base; a pivoting assembly; a molding template connected to the pivoting assembly; a holding device connected to the molding template, the holding device having a clamp jaw and a pivot configured to rotate the holding device relative to the molding template; and a locking mechanism configured to hold the molding template and the holding device in an open configuration such that the holding device can accept a first part of the plastic sheet and configured to release the molding template and the holding device such that the holding device is in a securing configuration that secures, via the clamp jaw, the first part of the plastic sheet to the first side of the molding template at the first longitudinal edge of the molding template. Methods for making the stair tread are described as well as the molded stair tread.