Second story addition using panels and pre-built roof – GreenBuildingAdvisor

Does anyone here have experience or thoughts on using panelized walls and a trussed roof assembled on the ground (all craned into place) as a way to add a second story addition?

It (or something like it) seems like the obvious way to go for a second story addition, but I have no actual experience with it, and it doesn’t get talked about much in that context.

My thinking is that craning the walls and roof (with at least sheathing on it, if not more) would not only significantly reduce dry-in time, but would likely save money. The most significant “drawback” I see written about is the need for planning and making sure things align. What other big picture issues am I not thinking about?

For context, the hypothetical project would be a simple 30’x34′ 8/12 gable roof. I live in Maine where you really can’t count on long stretches of dry weather. There’s plenty of ground space for assembling the roof assembly.

I am actually a bit perplexed how people manage to do second story additions conventionally. It would seem things are guaranteed to get soaked.