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.

Cedar and copper details don't mix well, for starters. In my area there was a tradition of slate for the main roof and standing-seam tin for porch roofs or other areas where falling ice would destroy the slates. Shakes tend to last longer than sawn shingles because they self-ventilate better, and they contain more actual material. I think now that cedar shingles last longer than 20 years ago (when they were failing left and right in a few years) because some better details have been worked out. The courses now get interfaced with a spun synthetic material so that water is not trapped between. Actual seamed-in-place standing seam is always going to be a great material and an appropriate look for an old house. I view with disdain the snap-lock fake "standing-seam look" materials. They don't have the same craftsmanship, appearance or IMO longevity as the real thing. Casey

Well, I have a low-slung rustic ranch and in my opinion, anything but the real thing or a really good faux shake looks wrong (unless the house has been modernized--I'm in a pretty big 1950s subdivision so I see a lot). I don't get any weather where I live now so I am less concerned about durability than you might be. But the old Tudors...different story! You want faux slate! :P I've seen some good metal wood-look roofs on Tudors. Since they're taller you don't always get as close as you do on a ranch. But there's always a bit that dips low, where you can see it up close, isn't there? You might need to just drive around and see what others have used that works, or check with a historical district in your area an see what's recommended. Ask the old house forum here at GW. When I was looking at paint options for my Tudor a few homes ago (the POs had roofed it with nasty flat "architectural" shingles so I was stuck there) I drove around Indian Village in Detroit for inspiration--if you have a similarly cool old neighborhood locally, spend some time in it. (All I can say about the durability of the treated shingles vs untreated is that they'll probably last longer in a fire. Haha you'd hope so at least!) Do see if you can get any recs at the old house forum. I don't think they'd allow you to misshingle up a cool old house. Here is a link that might be useful: http://ths.gardenweb.com/forums/oldhouse/

It can depend on what kind of "cedar" you are using. In the eastern half of the country, 'cedar' lumber is Eastern red cedar, Juniperus virginiana. In the western half, and especially the west coast, cedar is Western red cedar, Thuja plicata. Confusing because neither is a true cedar (Cedrus species) at all. Western red cedar is considered one of the most rot and decay resistant woods available and even with direct soil contact can be expected to have an outdoor lifespan of at least 15 years. Even in my winter wet climate, raised garden beds constructed from Western red cedar will last a good 10-15 years and fences as much as 25 years and more. My old garden had an untreated (no paint, no stain, just natural weathering) WR cedar fence along one side that was who knows how old when we moved in and was still there and functioning well 22 years later when we sold and moved out. Western red cedar is the go-to lumber here for any outdoor applications - fences, decks, wood siding, roof shakes, garden ornaments and trellises, pergolas, etc. If not available in your locale, Eastern red cedar would be a reasonable but not as long lasting a substitute. Pine, even pressure treated pine, would come in a very distant third.