This is because metal roofing systems use interlocking panels. Despite its light weight, metal roofing provides increased wind resistance when compared to other roofing materials. A lightweight roof is very useful for large and or old structures, as it helps to maintain the overall structural integrity of the building. Metal roofing is also lightweight, creates little stress on the load bearing roof support structures and can be installed on top of an existing roof. The study went on to say that re-sealing and insulating air ducts in the attic will save even more money. Cool-color metals are light, reflective colors, like white. This finding is based on the use of a strapping system of four inches between the plywood and "cool-color" metal on top, which provides an air gap between the plywood roof sheathing and the metal. Coupled with its better insulating abilities, metal roofs can offer not only a 40% reduction in energy costs in the summer, but also up to a 15% reduction in the energy costs in the winter according to a 2008 Study by Oak Ridge National Laboratory. On a larger scale, its use reduces the heat island effect of cities when compared to asphalt.
It does not get as hot as asphalt, a common roofing material, and it reflects heat away from the building underneath in summertime. Metal roofing can consist of a high percentage of recycled material and is 100% recyclable. Because of their longevity, most metal roofs are less expensive than asphalt shingles in the long term. Metal roofs can last up to 100 years, with installers providing 50-year warranties. The copper on the tower was renovated in 2009.
The roof at Kronborg, one of Northern Europe's most important Renaissance castles (immortalized as Elsinore Castle in Shakespeare’s Hamlet) was installed in 1585 A.D. Mary's Cathedral, Hildesheim, installed in 1280 A.D., survived until its destruction during bombings in World War II. Centuries later, copper and its alloys were integral in European medieval architecture. The Romans used copper as roof covering for the Pantheon in 27 B.C. In the 3rd century B.C., copper roof shingles were installed atop the Lovamahapaya Temple in Sri Lanka. Copper has played a significant role in architecture for thousands of years (see: copper in architecture).