A metal roof is a roofing system made from metal pieces or tiles characterized by its high resistance, impermeability and longevity.
It is a component of the building envelope. Zinc, copper and steel alloys are commonly used.
Metal roofs can last up to 100 years, with installers providing 50 year warranties. Because of their longevity, most metal roofs are less expensive than asphalt shingles in the long term.
Metal roofing can consist of a high percentage of recycled material and is 100% recyclable. It does not get as hot as asphalt, a common roofing material, and it reflects heat away from the building underneath in summertime. On a larger scale, its use reduces the heat island effect of cities when compared to asphalt. 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. 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 and the metal. Cool-color metals are light, reflective colors, like white. The study went on to say that re-sealing and insulating air ducts in the attic will save even more money.
Cladding is the bonding together of dissimilar metals. It is different from fusion welding or gluing as a method to fasten the metals together. Cladding is often achieved by extruding two metals through a die as well as pressing or rolling sheets together under high pressure.
• Best technique for coating any shape => increase life-time of wearing parts.
• Particular dispositions for repairing parts (ideal if the mould of the part no longer exist or too long time needed for a new fabrication).
• Most suited technique for graded material application.
• Well adapted for near-net-shape manufacturing.
• Low dilution between track and substrate (unlike other welding processes and strong metallurgical bond.
• Low deformation of the substrate and small heat affected zone (HAZ).
• High cooling rate => fine microstructure.
• A lot of material flexibility (metal, ceramic, even polymer).
• Built part is free of crack and porosity.
• Compact technology.