New industry research shows that metal roof systems can last at least 60 years, longer than the average commercial building’s service life.
“The study provides third-party, scientific data that backs up the long held belief that 55% aluminum zinc coated steel standing seam roofing systems offer economic longevity and can be better for the environment.
Non-metal roofing systems require one or more full replacements within a typical commercial building’s 60-year service life, which is more expensive over the long run and usually adds to the solid waste stream in landfills.
The study, sponsored by the Metal Construction Association and the Zinc Aluminum Coaters Association, was conducted with oversight of three independent consulting firms which analyzed low-slope, unpainted 55% Aluminum-Zinc coated steel standing seam roofing, in a wide range of environments across the U.S.
The material tested is commercially known as Galvalume and Zincalume and is commonly used on low rise commercial buildings such as warehouses, schools, distribution centers, shopping centers, government structures, sports and exposition facilities and other structures.
Mixed use buildings in which offices, stores, and, or, rental apartments coexist in the same structure have a life expectancy right now of 75 years. Apartment buildings show an average age of 66 years and college buildings hover around the 60-year mark–although, many of America’s oldest schools including Harvard, Yale, Princeton, Columbia, Rutgers, William & Mary and The University of Pennsylvania have campus structures with metal roofs well over 100 years old. Here, the perception of quality that metal communicates is important, not only for schools with a prestigious past but because the average cost of a typical college building today is about $5.2 million.
According to the Metal Construction Association, the study incorporated the results of multiple field inspections, independent laboratory analyses of metallic corrosion of the roof panels, components and sealants. It also included assessment of all integral ancillary components that impact the end of roof service life.
According to the MCA, the research team selected 14 building sites in five different climate regions of various geographies in the continental United States ranging from hot/dry to moderate/acid with the understanding that precipitation acidity varied considerably from one site to the next over this broad geography.
The research study concluded that the expected service life of an unpainted 55% Aluminum-Zinc coated steel standing seam roof constructed today in a wide range of environments using best practices can be expected to be in excess of 60 years.
The study also confirmed that these types of metal roofs resist corrosion even in “weak” spots, such as sheared edges and panel profile bends. Inspections showed an absence of significant red rust after as long as 35 years.
The study found that while low-slope steel standing seam roof systems were projected to last up to 60 years, ancillary components (such as fasteners) may need to be replaced during the roof life. But such replacements represented significantly less than 20% of a total roof replacement cost.