Galvalume is sheet steel coated with an alloy of aluminum and zinc. It is more corrosion resistant than galvanized steel but it doesnÂt self-protect scratches or cut edges nearly as well and it is also more susceptible to staining from corrosion at tight bends (tension bend staining) so it is used most commonly in simple profiles like standing seam roofing. Galvalume steel is very shiny so although it is sometimes installed unpainted, it is usually painted on a house. It must be cut with a shearing action rather than saw-cut. If the porch roof slopes are low you might consider running the metal roofing up the main roof a foot or two in order to protect that intersection. There are other precautions depending on your climate.

i have this combo, though my shingles are stained dark. the trim is white,the roof is dark charcoal. i think it looks super. i can email photos if you like, but am unable to post them.

Well, yes, it's possible.... but. That large amount of complex valleys, trim, and underlayment, will not be inexpensive. The flat metal is the cheapest part of a metal roof. It is not going to be easy to erase the home's identity and move it to "farmhouse". It has almost nothing in common with a classic farmhouse. It's pretty nice as an updated ranch though.

and Zahner Zinc could possibly stamp out some custom metal roofing if your roof pitch is steep enough. Or a decent sheet metal shop can bend up sheets of aluminum and do flat lock similar to millenium but in larger pieces. It's hard to get good installation with metal. They like to use a lot of caulk joints, which defeats the purpose The aluminum standing seam they keep telling you're thinking of is "Galvalume" style which is steel electro plated with aluminum somehow. Galvalume is still "ferrous" and would rot by the ocean if it found a good galvanitic reaction with something. What you meant in your title was "non-ferrous" . If you have a roof made from stainless or a non-ferrous metals like zinc, copper, aluminum, and it looks correct to someone who knows, there is no guessing as to how long it will last undisturbed.