b"Contractors Guide Quarterly Report: l\\1etallic Coatings for Roofing Panels Continued from page 7 roding. Tenlater,steelmmercially available to the yearsaluminizedbecame coroofing industry. Alumin coated steel retains the strength and for lity ummabiof the base steel and provides excellent corrosion resistance inrial industenviron And aluminum does ajob reflecting heat. ments.superior Like zinc, the coating of aluminum metallurgically bonds to the base steel; it forms an alloy layer betweensteelouterinum surface coat. theand thealumiseach The aluminized coatingapproximately 1.5 mils thick onside, using 0.65 ounces of alu per square(bothand it depends on its minumfootsides), outstanding barrier protection to fight thents. Unlikenc, th is little eleme zi ere cathodic protectionby aluminized steel. Whilealumin coating offeredtheum offers excellent barrier protection, it is more delicate than zinc. Aluminum is practically inert - it doesn't react m with other elements and is not water uch soluble so it's not going to sacrifice itself to protect the base steel. A deep the zinc on the outer surface accounts for the natural spangled appearance ofscratch or sheared edge will beg to rust quickly and will require m ninai teTheyabusepa urgalvanized panels.also can be treated to eliminate or minimize the span nance. Be careful not tothenels d ing installation and don't use gle.panels that have been scratched or nicked. The durability of the aluminumalso varies according to environcoating Aluminizedmental conditions but,no sacrificial,rate because there ischaracteristic itsof Theprocessof hot dipping steelinmoltenaluminum wasdevelopeddecay is relatively slow when compared to zinc. around the time of World War IIalternative way to protect steelcar-as anfromContinued on page 12 YOU'RE REALLY GOING TO H . THER~!.~~~pp~!~~1\\ ?~~That's why, for a limited time only,we're throwing in a' FREE SLATE HAMMERwith our genuine North Country Slate products~ Our s1ate is drawn from the finest' most demanding North American and European standards.\\ variety of colors, textures and sizes, ideal in every situationlwhere quality, durability and visual appeal are important. And since we're com to maintaining mitted a significant inventory to service our customers better., you don't have to worry about waiting to get to work.So call in North Country Slate on your next job, and we'll hammer home the extra advantages. Can you handle it? NorthSlate Country Tel: (416)724-4666; toll-Free: 1-800-975-2835; www.ncslaJe.com *ubject to minimum purc'hase.ROOF S8"