I am going to be putting a steel roof on my house, but I have 4 in copper plumbing vent pipes. Is there something I can coat the pipes with to insulate them to prevent them from causing galvanic corrosion, or should I crawl into the attic, hack them off, get the proper fittings, and extend them through the roof with PVC? Or is there another solution.
The pipe boot will have a neoprene collar, so there shouldn’t be any contact between the copper pipe and steel roof panels.
I suppose I should have elaborated a bit. I understand the neoprene, as well as the galvanized pan of the pipe flashing will prevent direct contact between the copper pipe and the roof panels/shingles. What I was concerned about, was water running down the upper exposed portion of the pipe above the neoprene collar. I have read about condensation on copper coils on roof mounted AC units and such, dripping onto the steel roof below and causing corrosion. I would just figure rain dripping down a copper pipe and then onto the roof would do the same.
I see what you mean. I wouldn’t worry too much about it as the paint is another barrier, but if you are really concerned, by all means do your idea of using pvc pipe.
Paint is all you need.