The Smithsonian Arts and Industries Building (AIB) features an array of functional and decorative ironwork, both inside and out. Wrought-iron trusses support the roofs of the building; the staircases within are constructed predominately of cast iron, though some original wood stairs remain (particularly in the towers). Many of the rails along these iron stairs have decorative motifs, as do the gallery railings designed by architect Victor Mindeleff (1860-1948) during the Hornblower and Marshall era of National Museum renovation.
The exterior of the AIB is adorned with decorative vents and acroteria (architectural ornaments); these decorative elements were originally made of galvanized steel, and were reconstructed in the 1980s of coated stainless steel. There are various ornamental accents at the Rotunda, over the court monitors, as well as the towers and pavilions. The ornaments over the slate roof at the towers have decorative edging; the original finish included gold leaf, which was not replicated in the 1980s restoration. Other decorative metal features include the cast iron gates at the north, west, and south entrances of the building.
All the windows at the basement and first floor of pavilions and first floor towers feature metal grilles, which is as much for museum security as it is for design.