Mark, I don't know anything about metal roofs and how a skylight would work with it. But I've helped put in a few skylights, the only regret I've had is that they weren't the kind that opened. Being able to open can give some great ventilation. I've never had any problems with them leaking. Pretty much they are like any other kind of window. The best way I've heard to install them is to build a box and install the skylight on that box.