The History of Metal Roofing
Since the 19th century, metal roofing has been a popular choice in building and architecture. Before this time, only lead and copper were used for roofing. Copper was most commonly used for more elaborate roofing, and lead used primarily as a protective flashing material. These metals were used to cover the surfaces when standard materials like wood, slate, and tile were not appropriate for the roof pitch or shape.
The History of Metal Roofing
Copper roofing with standing seams was used on more notable pieces of architecture such as the Christ Church in Philadelphia. Flat-seamed copper was also ideal for covering domes and cupolas. At the start of metal roofing, all copper sheeting was imported from England but at the end of the 18th century, facilities developed in America to roll sheet metal.
Sheet iron was the first metal to be produced in rolling factories and was manufactured first by Robert Morris, a Revolutionary War financier. His New Jersey mill was responsible for producing the roof used for his mansion as well as the replacement roof for Princeton’s Nassau Hall which was destroyed in 1802 by fire. Not long after, sheet metal became one of the most popular materials for roofing. Iron needed to be corrugated to be used for roofing. This process was patented in England in 1829. Corrugation stiffened the metal so that it had a greater span over lighter frameworks. These corrugated iron sheets also reduced the amount of time needed for installation which also meant lower labor costs.
The next metal to be incorporated into roofing was zinc, in France in 1837. Galvanizing zinc was done to protect the base metal from rust at first, but by the 1850s this zinc was used for post offices and customhouses, trains sheds, and factories. One of the first metal roofs in the South was installed in 1857 on the U.S. Mint in New Orleans. The Mint roofing was designed to be fireproof with galvanized, corrugated iron sheets. In Canada, the metal roofing was tinplate iron and eventually, this became used in the United States as well. Thomas Jefferson was an early advocate for tin roofing installing it on “Monticello” and later the Arch Street Meetinghouse was covered with tin shingles laid in a herringbone pattern. Tin plating was often confused with the terne plate, which was iron that was dipped in an alloy of lead and tin. It is unclear how often terne plating was actually used as documentation over time confuses the two materials.
Tin became one of the most common roofing materials as rolling mills become more established, thanks to its lightweight and low-cost traits. Zinc was also used throughout this time as a less expensive alternative for the lead. However, the advantages of zinc were controversial so it never ended up being widely used across the country. This left tin to be the most commonly used metal in roofing.