I believe the Sun Tower dome was painted to look like a copper patina for Expo 86. If they do make it copper then it would be a number of years before it turns colour. I wonder how long that process takes? Does the Graceland tower have a copper roof?
Speaking of new roofs, I've been looking at the new one on Christchurch Cathedral and it appears to be smooth metal. I think the old one was traditional wood shingle and I'm surprised that the new one is such a radical departure from the original. Here's a quick pic from the bus a couple of days ago. I'll try to get a better one soon.
Oct.23 '16, my pic