Phaneuf doesn't care for metal roofs on residential homes because it's difficult to get a tight fit around chimneys and vent pipes that penetrate the roofing material. Caulking is required in such places and it must be checked regularly to prevent leaks. However, because of their slick surface, metal roofs quickly shed rain and snow. And they are fireproof. Slate roofs are often seen in the North Country on churches, schools, train stations and a few grand old homes.
Slate is actual stone that splits naturally into thin uniform thicknesses.
It is cut to uniform sizes, like shingles, and is pre-drilled for nailing. They are highly resistant to fire from falling embers. With regular maintenance, a slate roof can last for centuries. I've done work on the Crown Point school for many years. It was built in 1860.