Dissimilar metal flashing on metal roofing

Guest User
I understand the general rule of not putting dis-similar metals together for corrosion/electrolyte problems but am confused regarding the aluminum vent stack flashing on stone-coated roofs for example. Aluminum is very maleable, so can be bent around battens etc. but am wondering whether that can set up a corrosion problem if the bare side of the stone-coat shingle touches the aluminum. Some "no-calk" pipe flashings with the rubber center have even been supplied with a stone-coat order from a distributor. So what's your opinion? Dick in Washington
Todd Miller
Isaiah Industries, Inc.
Some stone-coat products may have a clear coat on their back side. I would inquire with the roofing manufacturer. You could separate the two with a coat of paint or roofing mastic or sometimes with underlayment.
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