What do you contractors think about all these screwed on metal roofs? Do you think they are gonna hold up?
In our area we refer to the ag panels as "chicken coop roofing".I personally would not have one installed on my home,it's a given they will leak and I think they make a home look cheap.I've seen contractors installing them over shingle roofs that have rotted decking,real nice.If you really want a metal roof,get out your checkbook and get a 26 or even better 24 gauge true standing seam metal roof.
It takes a year for the wood to darken around the screws. After that, the amount that shows as actual water varies. It'll last until it leaks. You might even be safe holding your breath waiting for it to happen. :)