No, if it does not come up with the tear-off, it's fine to leave it there. It should be covered with the new underlayment though.
Todd Miller
2018-01-25 16:36:01.000000
I'm having our 24 year old shingle roof replaced with a metal roof. Aluma (?), 24 gauge. The installers stated that the shingles, of course, come off, but not the felt between the shingles and the original wood panels under the shingles. They are also using the usual plastic-like felt underneath the metal itself. Is it necessary to remove the felt on which they original shingles rested on since the day the roof was installed?