For as long as people have been able to afford it, metal has been made into sheets and used for architectural purposes, from roof coverings to sewer pipes. In the late 17th century, this hand hammering process was then replaced by large "rotating iron cylinders" that pressed the metal into flattened sheets (Simpson 31). These water rolling mills made it possible to obtain more uniform sheets as well as a less laborious and less time-consuming process. The sheets could be made thinner, which was advantageous when creating smaller details, such as gutters and roofing. The process of creating sheet metal has evolved, creating a better product. The first materials used were lead, copper, zinc and iron; steel was introduced as another material in the late 19th century. Lead was mainly used for roofs, gutters and downspouts. However, it was soon discovered that due to the harsh climates, the expansion and contraction of the metal meant that it would tear easily. As a solution, it was melted and mixed with tin to form an alloy used as a coating. This provided a more stable building material (31). Copper was also used because it was more durable and lighter than lead. As it was, tin was another material, but it was too soft to use on its own. For this reason, it has been combined with other materials, such as iron, to obtain a more aesthetic exterior covering. Although it could cost almost twice as much as an iron roof, it was guaranteed to last three times as long (32). Due to its cost, it was only used for the roofing of important buildings, while smaller decorative details were used on less significant commercial and residential structures. Copper became a less popular material to use for ceiling tiles because...... middle of paper...... company, which in its 1911 trade catalog, stated this notion (citation). However, it soon became clear that the small mistake a customer would make when attempting to install the ceilings themselves made the ceilings less than satisfactory. It was discovered that the truly difficult installation process should only be carried out by the trained and competent professional necessary for proper installation. Brian Greer's tin ceilings. “History of tin ceilings”. Brian Greer's tin ceilings. Brian Greer's tin ceilings. Internet. November 5, 2013.http://www.ehow.com/about_4674151_history-tin-ceilings.htmlhttp://www.americantinceilings.com/installing-a-tin-ceiling-pg1.htmlhttp://www.thisoldhouse.com/ toh/photos/0,,20437428,00.htmlWorks CitedW.H. Mullins, sheet metal architectural ornaments, statues, cornices, building facades, finials, etc. (Salem, OH: W.H. Mullins, 1894).