We had originally planned to do a sod roof (just as we had originally planned to build a round house). In the end, metal roofing seemed to fulfill more---though definitely not all---of our often conflicting project goals. The advantages include ease and speed of installation, longevity and low maintenance of the material---and the fact that snow might tend to slide off a metal roof far more easily than other materials, even at our low 1:12 pitch. A sod roof, while it would moderate inside temperatures, use greener (so to speak) materials, and help the house blend with its surroundings, would have required us to engineer for a far heavier roof and snow load, and would have taken much longer to install.
Next step was to install fascia boards, eaves, and soffits.
Joe rigged a kind of cantilevered scaffolding out of 2X4s (Brian's idea, I believe?).
Now to get sixteen 30-foot panels onto the roof. Levers and pulleys would have helped---large mechanized equipment even more. As it was, we fortunately had the power of son Ian to help. Suffice it to say that it took a lot longer---and was far more painful---to get the panels onto the roof than it took to line them up and secure them. It was what you call a character-building experience. Screwing them down seemed easy after that.
The roofing came with these nifty foam inserts to plug up the peaks of the roofing panels.
The metal roofing hangs over the plywood substrate by a couple of inches. This is so gutters can be tucked under the sheathing, so that water will flow directly into them rather than down the fascia boards.