Amazing New Ideas

How-to-install-corrugated-roofing-over-shingles, hunker may earn compensation through affiliate links in this story. notching is making a v-shaped cut in the metal. a metal roof is an alternative to a shingle covered roof, but a metal roof can actually be installed over shingles. however, you should only install a metal roof over shingles if you have less than four layers of shingles on the roof.