Metal roofing is anything from corrugated metal that is used on barns all the way up to formed architectural white shingles that happen to be metal instead of composite materials. They have a number of different properties that make them desirable. One, is that they tend to have a much longer lifespan. Two, is they tend to add significant value to the home.
A house that doesn’t have a good roof is fixer-upper. A house that has a good roof is a house that is like the rest of the market. A house that has a metal roof is generally worth more than the market because that metal roof has an implied value much higher than the neighbor with composite shingles because that metal roof is going to last 2 to 3 times the amount of time that a shingled roof would last in that same environment.
All metal roofing is not created equal. There are standing seam metal roofing options which essentially have a seam that is a fold in the roof every 8 to 12 inches wide. These roofs are adapted commercial roofs that people started applying to residential homes. They’re not ideal for a number of reasons, mainly because when the metal expands and contracts due to the heat it absorbs, the metal itself will start to burrow and while the roof looked great the day it was applied, they start to look wrinkly over time.
The real option for a homeowner who wants to go with metal roofs are roofs that have tiles or panels similar to the size of a shingle, maybe sometimes as much as twice as large as a shingle but still in that general size parameter. Those shingles float so that they allow expansion and contraction without buckling. They also positively lock to each other and, hopefully, to the other facets of the roof, mainly the flashing.
The highest quality material would be copper. Copper roofs have proven their longevity in the 3 to 400 year range. They’re also more expensive than aluminum roofs by a factor of 3. Aluminum roofs tend to be more expensive than high quality composite roofs by a factor of 3, but aluminum roofs have shown longevity demonstrated in the 50 year category and the only reason they haven’t demonstrated longer is aluminum roofing isn’t that old of an industry although it’s predicted that they should surpass a hundred years in duty cycle.