I have a small (18' x 24') mountian cabin with an alum. Metal roof.
This has begun to leak, and I'm destined, next week , to go and
re-pound the nails, and replace the loose ones with roofing
screews/washers.

What I am curious about is where in the roofing should the nails be
located??

The roofing has roughly the following profile

-----------/\---/\------------/\---/\------

with a set of 'peaks' about 2 " from the edge. It would seem to make
sence to nail in the valley between peaks, but I have know clue, if
that is correct...

Any Ideas????

Thanks for your time...

Mike