galvallume vs. galvanized

Guest User
1-What is the difference between galvanized steel standing seam roof and galvalume steel standing seam roof? 2- What is the difference between a field form standing seam roof and a shop standing seam metal roof.
Allan Reid
Dura-Loc Roofing Systems, Inc.
Galvanized steel is metalic coated with Zinc in various coating weights. Minimum recommended for painted metal roofs is G90. Galvalume is a zinc and aluminum coated steel that becomes an alloy and is recommended in either painted or bare applications with a minimum coating weight of AZ50. Galvalume has an excellant performance life in bare exposures. Hence if you are usinga bare panel use Galvalume and if painted use either. As to Standing Seam, this term is used all too loosely. In fact the original name was staning seamed roofing where the joint is mechanically rolled and hemmed after installation. Some SS roofs come with floating clips and some with fixed clips and really depend on the sheet length and slope of the roof. Most SS roofs are commercial hnd have certaing wind and structural performance characteristics. There are a number of residential vertical rib products offered that have concealed fasteners much like a standing seam. They can be ordered preformed from a factory or site roll formed on a portable machine. Either or chech the brand and see if the machine manufacturer stands behind the product and that it carries all the appropriate approvals. There are a number of very qualified sheet metal shops that will custom form metal roof panels on a press brake in limited lenths as well. Hope this helps make sense of it all. You may be referring to a snap loc vertical rib panel
Guest User
How can I tell the difference between a galvanized and galvalume R-panel roof that has been factory finished/painted? How long has finished/painted products of each been around? How does each handle rust?
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