I am having my 3 tab asphalt roof replaced, with a laminate asphalt.( looks like a shake shingle design), 3 ft. ice and water barrier on entire perimeter of roof.
Currently there is galvanized valleys, the roofer suggested that I do away with that and do what they call a closed valley install.With a 3 ft ice barrier underlayment put down before the shingles in areas,where the current galvanized valleys are now.
I have heard of that before, it does look like a cleaner install as the galvanize weathers and discolors.
Thanks Tom