A growing trend in construction is the use of masonry walls with pre-engineered metal building systems. While masonry walls remain the first choice of designers and builders for fire, sound and impact resistance; security; durability; energy conservation and aesthetic appeal, metal building systems have certain advantages. For example, metal building systems are one of the most economical ways to create wide-span structures that allow interiors to be laid out without regard for column locations. Metal roofs have improved considerably since the days of corrugated galvanized iron, and modern standing-seam metal roofs now provide exceptional value and service life. When designing or constructing a masonry-metal hybrid, the differential movement characteristics of the two building systems must be considered. The thermal expansion and contraction of steel is much greater than that of masonry and is of special concern in long-span structures. The ductile nature of steel allows pre-engineered metal buildings to deflect or "sway" in the wind and under the influence of earthquakes or other horizontal live loads. Masonry structures, on the other hand, can accommodate relatively little horizontal movement without cracking. Additionally, the shrinkage of concrete masonry and expansion of clay brick does not occur in a metal building and must be considered. The most practical way to accommodate these differential movements is through careful detailing of the masonry rather than by trying to restrain the metal frame. Partial-height masonry walls, or wainscots, are commonly used on metal buildings. Even when metal panels are used on the upper reaches of the wall, a masonry wainscot provides increased security and damage resistance at the base of the wall. The combination of the two materials also reduces the visual scale of a large building and improves its overall appearance. The simplest way to construct a wainscot is as a freestanding cantilevered wall. A cantilevered wall must be built without structural connections to the metal building frame and located far enough from the building frame to accommodate any anticipated deflection. While a structurally independent wall may be simplest, it is not necessarily the most efficient method. Part of the economy of a metal building is that all its components work together to form an integrated structural system. To optimize the masonry-metal hybrid, it may be wise to look at ways to integrate the two materials.