Metal roofing has been used as a weather barrier on homes and office buildings for over 4000 years. Metal roofs has always been a long lasting, weatherproof barrier against the elements. Copper was the original metal used for metal roofing, because of its abundant supply and ease of processing. It has served a dual purpose of keeping water out of the structure, while also adding a means for collecting rain water for drinking use. Because of its resistance to earthquakes and lightweight nature, metal roofing panels were passed from home the home as a structures needed to be rebuilt. As iron and bronze were developed, more forms of metal panels were developed for cladding of armor, protection of the elements, and of course protection in the home. Through all of time, metal roofing has shown that it will outlast all other roofing products. Many roofs in ancient Europe still have their original metal roof on their structures.
Just like the metal roofing stemming back thousands of years, today's metal roofs are very strong, lightweight, and fire-proof (remember that on the 4th of July). The metal is now made from steel, coated with baked enamel paint, and comes with a 40 year to warranty against fading or peeling. The paint contains UV inhibitor which will bounce some of the sun right off, so you house is actually cooled by the roof! Contrary to belief, when it rains hard or hails, there is no more noise from the metal roof than any other kind of roof because of the substrate that it's sitting on.
The Historic Union Station in downtown Portland was originally built in 1896, and its metal roof was replaced in 2011, one hundred fifteen years later!