I currently have a metal roof on my 1911 house. I am considering replacing the roof with a shingle one. I would like to know the pros and cons of metal vice shingle: cost, upkeep, life expectancy, etc. Right now I am having to recoat the roof every 2-3 years at a cost of $700 per treatment. Is this reasonable? Note: this is a black-painted roof (would a shingle roof be more energy efficient?). The home is a two-story. Also, to install a shingle roof, what would be a reasonable cost (2,000-foot home).