Galvanic action can occur in the situation you have described. You may be fine for many years using a high quality galvanized fastener but I'd prefer you to be safe rather than sorry. The potential for problems of course increases the closer you are to the salt coast line.
Todd Miller
2015-01-04 06:49:14.000000
I have some aluminum roofing panels I am installing, and it is recommended that i use only aluminum or stainless steel fasteners. All the fasteners will be concealed however, and although it is damp for part of the year I am not near the ocean at all. For steel panels I've used the Teks style truss head screw, with no coating at all. I am curious about the galvanic reaction if I use regular or galvanized steel fasteners for the aluminum panels, given that they will not be exposed to any direct air or moisture other than what gets behind the panels?
I understand why the recommendations are in place, but should I be really concerned about the concealed fasteners corroding and my roof flying off in 20 years?
Al Thelas
2015-01-03 23:58:04.000000
+1
Don't skimp here.
You could end up with a roof that is worthless 10 years down the road.
I have seen dissimilar metals eat themselves apart after a number of years.
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