Some of the oldest and most ornate buildings in the world owe their luster, at least in part, to metal roofs which cap their escarpments. Across Europe, cathedrals and castles have survived for hundreds of years, in no small part, due to their metal roofs that have held out the wind, rain, and snow that threatens to deteriorate their structural timbers. In north America too, many buildings dating back to colonial times, have stood the test of time clad with metal roof to protect them.
Since humans moved out of their caves, perhaps ten thousand years ago, and began constructing their own shelters, finding affordable and effective materials for use in roof construction has been a challenge. Every part of a building, the foundation, the walls and floors, the roof, they all have a purpose, but it is the roof which will face the harshest conditions mother nature can throw at it.
Day after day, year after year, a roof must face a relentless blazing Sun and harsh ultraviolet radiation that would exact a toll on almost any material. Add to that being pelted with rain, punished by wind, pummeled my hail stones and peppered with bird dropping full of nasty little corrosive enzymes. Yes, we humans ask a lot of our roof and the materials it is constructed of.
About 5000 years ago, humans first began to smelt and work copper, and found this malleable metal could be hammered and fashioned into thin plates which could be used as roofing shingles. Over time, they noticed that this ductile metal stood the test and weathered the beating delivered by the elements, and they saw that the metal roof was good. To this day, there is no material which surpasses in longevity, nor perhaps aesthetic value, the copper roof. If there is any drawback to the use of copper as a roofing material today, cost would be the most likely factor. But, when you consider that a copper roof can be expected to out last several human life spans at least, maybe copper has a more sustaining value.
Today, copper is not the only metal used for roofing applications. Tin, steel, and aluminum, offer less costly alternatives to copper while possessing many of the same attributes. The first advantage of all metal roofs is of course durability, but there are a lot of other reasons for considering a metal roof. While not as fire resistant as tile or slate, a metal roof is leaps and bounds ahead of composition shingles or wood shake roofs with respect to fire protection. In fact, cedar shake roofs have been outlawed in many states for this very reason, and metal has become the preferred alternative over tile in areas where snow load demands a higher pitched roof.
A metal roof will generally be a cooler roof, as metal tends to reflect heat back into the atmosphere, whereas tile and other materials tend to absorb and retain heat more. This can provide substantial energy savings in areas where air conditioners run all summer. Metal roofs are the best when it comes to snow, because snow is more apt to slide down a metal roof than other types. New techniques of double lapping seams in metal sheet roofing make this type of roof almost impervious to water infiltration. A properly installed metal roof can also be less prone to wind damage, than shingles or shakes.
In the final analysis, metal roofing has many advantages to offer, over almost any other type of roofing. Its one disadvantage, might be that a metal roof will generally cost a little more. But taking into account that a metal roof will outlast other types of roofs, maybe it's the all round better value.