Steel is the most suitable material to use to support facades in circumstances where glazing has to be supported over distances of more than about four meters for commercial glass roof. The strength and stiffness of steel is such that supporting elements are of smaller section and therefore less obtrusive than would be the case with other commonly-used materials such as aluminium.
Tubular and tension elements are used in atrium roofs of commercial glass roof to form elegant and minimally intrusive support for glazing. Large deflections can be managed by careful detailing of fixings to glazing, such that local bending of the glass is avoided.
Atria are common features of office buildings where the layout involves large floor plates. In shopping centers, the external walls tend to have few windows and stores generally face onto an internal"street" which is extensively glazed at roof level. The roof glazing allows natural light to penetrate deep inside the building for the benefit of the users and to reduce the energy-consumption of artificial lighting.
The structural systems used to support these roofs are designed to maximize the amount of light entering the building, using members of the minimum width possible. Tubular members are often used and painted in a light color so as to absorb as little light as possible.