I was given a quote to install a metal roof over the existing shingles. The shingles are very curled on parts of the roof. Is this an issue? The installer stated the curls would break off when they are walking on it during the installation.
I suggest two things.
1) Always a layer of underlayment over the old shingles.
2) Send a picture of the current roof to the manufacturer of the metal roofing and get their input.