One of the most rewarding aspects of installing a roof is the knowledge that you have provided excellent, long-lasting value for your customer. This applies not only to workmanship, but also to the materials used for the roof. When metal roofing is selected, the choice of Galvalume® sheet roofing panels is frequently made. This product consists of a steel-sheet substrate coated on both surfaces with a 55-percent aluminum-zinc alloy coating (ASTM A792). The product is widely available around the world and has been successfully deployed in the construction marketplace since 1972. Yet in that time period, the actual Galvalume panel service life has not been firmly established, primarily because end of life for properly installed Galvalume roofing panels has not been observed on actual roofs.
For more than 25 years, visual field inspection surveys of low-slope roofing have been conducted on a regular basis by roofing industry professionals in attempts to get a handle on this product’s expected service life. While these surveys have continued to report excellent overall performance, the fact remained that a more quantitative method of assessment was needed. Such a method has now been developed. This novel inspection and analysis method, peer-reviewed and published in the Journal of ASTM [1], involves analytical corrosion measurements of Galvalume standing seam roof (SSR) panels, plus visual assessment of associated roof ancillaries, including sealants, fasteners, flashings, curbs, gutter systems, roof penetrations and profile closures to predict the service life of the total Galvalume SSR system when built using today’s best practices.