A metal roof does that, it's ok. You can't make a horse a bear, right?

It acts like a giant mirror shining on neighbouring home

You should offer to paint it before the neighbors decide to complain to the city about it, and they take action. I wouldn't be at all surprised if there isn't some sort of code against it, and in the town where I live, if you get cited, it's a $1,000 fine for each occurance. And every day it isn't dealt with is an occurance so it's a $1,000 a day fine. Be a good neighbor and deal with it before it causes hard feelings with you neighbor.

Being in Canada, with a metal roof you will need both larger gutters and snow blocks for that roof before the weather turns. You should check with the company you find to install the snow blocks to see if they have any suggestions.

Also, have you discussed this with the company that installed the roof?

Rather than paint, couldn't it be treated to "age" a bit to take the glare away ?

"Blackmurphy", did you ever run across a viable option? I just installed a metal roof on my house and my neighbors are miserable. Painting / coating the new roof voids the warranty and trying to grow tall trees to block the glare is not an option.

"Bozthree" : I have identical situation except that my Galvalume roof is on a 9' x 9' gazebo and one neighbor is complaining. I cannot paint it because it voids the warranty. Growing trees or aging takes a few years. I want to be a good neighbor with a happy neighbor across the property. I have yet to find a workable cheap solution that will cost me more than the roof itself. If you have any ideas, please post it, for example, put a tarp on the roof, install a plexiglass/plastic barrier, etc.

"masohal" : I have offered to buy sun-block type shades for the neighbors. They told me not to worry about it. The other neighbors complain about EVERYthing so they won't get the time of day from me. Re City Hall: my contractor, roofer and I attended special hearings to get the permit. So we jumped thru all the hoops before it was installed.

Natural dirt or tree sap takes care of theistic pretty quickly.

"Bozthree," Are you comfortable in telling me the city you live in. I am in Dublin, CA. I was just "repairing" the old wooden roof on the gazebo and did it myself. Maintenance of existing structure may not be same as a big job. Did city give you hard time or were easy to give you a permit. I just want to know that.

"masohal" : Franklin, WI. Got permit after 15-minute discussion and handling of actual material. An "anonymous neighbor complaint about the color" shut down work 2 days later, then City Hall realized their error in shutting down work, but wintry weather held off the roofers another 2 weeks. It was a cluster. By the way, the color is "ash grey" sort of a beige/grey color. VERY offensive. (I'll try to post a photo.)