Curtain walls are exterior walls or facades that do not provide any type of support to other sections of the structure. As such, the curtain wall does not bear any of the weight of the roof or any of the other walls. While a wall of this type is sometimes only decorative in nature, it can also serve a couple of important functions. One of the more important tasks of a curtain wall is to effectively function as a wind break for the remainder of the structure. Doing so helps to minimize the degree of erosion on the are of the building where the curtain wall is places, as well as helping to provide some degree of insulation from cold winds during a storm. The end result is that less stress is placed on the heating and cooling system of the building, thus keeping utility costs lower than they would be otherwise.

       Along with serving as a wind break, the curtain wall also can help minimize the buildings exposure to rain. By deflecting a portion of the rain, the deterioration of the building is delayed somewhat. In addition, the deflection qualities of the wall help to minimize the incidence of water collecting and draining into any small cracks that may be found along the building surface.

      To some degree, a curtain wall provides the same benefits as a storefront system. The main difference is that the storefront system usually spans a single floor, while a curtain wall may be constructed to provide protection for several stories. Curtain walls also tend to lend themselves more easily to homes than the systems designed to protect storefronts.

While it was not unusual for a curtain wall to be constructed with a steel frame in times past, aluminum is often the metal of choice for the frames and gridwork that make up the surface of the wall. Glazed windows are frequently utilized in order to allow the maximum amount of light to move through the structure and to the interior. However, there are examples of the curtain wall that include opaque panels of spandrel glass, a frosted window system that can be opened and closed at will, or even decorative metal panels.