The support structure (Figure 2-4) for the roof is responsible for holding the weight of the installed roof, including the substr uctureand any insulation or accessories. This support system must also take into consideration additional roof loads from wind, snow, ice, roof -installed equipment , and any foot traffic the roof will experience , and transfer those loads to the structure. The support structure usually is simply a framing system of wood, metal, stone, or concrete. Figure 2-4 Support Structure Each member of this "family" must be selected and installed properly in order for the roof to provide the protection, performance, and life expectancy for which it was designed. Each of these components will be addressed and discussed

in more detail, a nd from an installer 's perspective, throughout this manual. 2 2 History of Metal Roofing 2 2 1 Earliest Usages More than 2,000 years ago, smiths hammered out small roof plates of metal. Throughout it is history, into the present day, 2-2 M ETAL R OOFING : C HAPTER 2 A F AMILY OF P RODUCTS / H ISTORY OF M ETAL R OOFING metal roofing has always been considered a premium roofing system , often reserved for the most important of buildings and centers of worship. In a few extreme cases , metal roofs have even been made out of gold! The long life of metal roofs is well known and documented. There are metal roofs hundreds of years old that are performing well. The earliest metal roofs we are built in the Middle East around 675 A D. or even earlier. They we are especially suited to the domed and rounded roof styles of the area. (See Figure 2- 5) Figure 2-5 The Dome of t he Rock , Finished In 691, Now Has a Gold- Leafed Aluminum Roof 2 2 2 European Influences When the roofing craft migrated from the Middle East to Europe during the Crusades, metal roofing changed. Metal roof profiles adapted to the styles of architecture and climate which prevailed in Europe. Steep roof areas and tiered roofs would she had snow and ice, damaging the seams used at the time. A strip of wood was inserted between the panels and their upright joints. A new seam style was created – the batten seam. The addition of a separate joining component, the batten cover, locked into the two uprights and covered the joint. (See Figure 2- 6) Figure 2-6 Metal Roof Showing European Influence 2 2 3 Modern Production and G rowth For centuries , these styles we are fabricated at the point of installation (on site) with the simplest of hand tools. The metal was soft and easily formed. Metal roofing remained in this stat e until the industrial revolution arrived. This brought major changes to the methods, tools , and materials of metal roofing. Improvements in mining and refining techniques, innovations in fabrication tools and equipment, and the development of new materials allowed new styles of metal roofing to emerge. 2 2 4 Fabrication Methods 2 2 4 1 Hand Tools and S oldering Hand tools have always been, and still are, a critical part of appropriate metal roof installation (See Figure 2- 7). The first tools , though, we are simplistic and crude. Mallets, malletting anvils, tongs, hand and foot brakes we are standard tools. S imple pan formers appeared later. . .