The open stairs have a bearing structure in view located under the staircase itself (single or double beam, modular central structure) or lateral (double side band, even modular).
In most cases these stairs are made of metal, with iron or stainless steel bearing structures. Their construction is based on their work up and flight, in order to assure the best payload: they are fully pre-assembled at the factory before being delivered to the installation site.
The metal open stairs can also be modular, with single central beam, with straight or helical work up and different colors.
Special finishing are also available: rust oxidizing, treatment, metal burnishing and brushing. Treatments giving a touch of originality to every open stair.
The steps of the metal open stairs can be made of wood (any wood), plate glass or marble; the railings can be made of a mix of steel and iron (to fit with iron structures), of pure steel, of plate glass (float or extra-clear etched glass) with or without pillars and handrails.
Sometimes the open stairs have wooden bearing structures: thus the stair will result to be fully made of wood.