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TOPIC: Research/Data

Looking for a comparison resource

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I am in the process of doing a comparison chart for the different types of materials used in standing seam metal roofing (in particular - copper, stainless steel, terne-coated stainless, HDG-90, Aluminum, and Galvalume). What I am looking for is comparisons on corrosion resistance, tensile strength, heat/fire resistance, dent resistance, and expansion/contraction coeffecients. Also I am looking for a list of materials that would cause a "galvanic reaction" or dissimilar materials for said products. Does such a resource exist? Or do you have that information available? Thanks, David
DavidD DavidD

4/8/2003
Hi David! This sounds like quite a project you have going. As far as dissimilar metals, what you are looking for is the "galvanic scale of metals" which lists metals from anodic (least noble) to cathodic (most noble). The further apart that two metals are on the scale, the more likely that the anodic metal will sacrifice itself to the cathodic metal if they are in contact with one another. The galvanic scale is easy to find with an internet search. As for the comparison chart, I am unaware of any such chart already in existence although, of course, physical properties of the metals are known and can be researched and found. However, when it comes to roofing and many of the factors you mention, there is more at play than just the metal types. Metal thickness and panel profile really affect things like impact resistance and even life expectancy. In many cases, because not all metals are as available as other metals in various profiles, etc., it is tough to do an accurate "apples to apples" comparison of many of the issues you mention. Also, coatings on many of the products will come into play by offering additional corrosion protection. If you'd like, please contact me direct and I will do my best to help you through the chart. My number is 1-800-543-8938 ext 201. All Best. Todd Miller Todd Miller
Todd Miller
Isaiah Industries, Inc.

4/8/2003
We have a cabin in the San Juan Islands in Washington state. We currently have a thick butt shake roof that has been on for 25 years and now needs replacing. We collect rainwater for just about everything we do, except drinking water. We would like to use the roof water for safe drinking water, but do not know what metal material to use for the roofing and whether it should be painted etc. Do you have any ideas for us.
Guest User

4/2/2004
There are numerous areas where water, for drinking or just other purposes, is collected from metal roofing. However, due to potential liability and the difficulty in ever ascertaining what might have been the root cause should one of the occupants later contract an illness, I do not believe there are any metal roofing manufacturers condoning this process. If any manufacturers read this and believe otherwise, please let us know!
Guest User

4/3/2004