How To Install Metal Roofing Over Shingles - Youtube. The first is to apply an approved underlayment over the old shingles. Asphalt roofs typically last 20 to 30 years, depending on the installation and shingle quality.
Installing a metal roof over shingles. It will also give you a nice, flat surface to install your panels on. Align the first metal roofing panel so that it overlaps the edging by 1/2 to 3/4 of an inch and is square to the roof line.
The second way to install a metal roof over a shingle roof is with the use of purlins or battens.
Installing a metal roof over shingles. Next, lay the shingles, working from the lower corner of the roof upward. First, you will need to install a base for the metal sheeting. The furring strips are 1x4 pine boards.