I have a porch roof that is leaking. Its a very slight pitch. I have replaced these before (many years ago) and almost remember how to do it. The issue is that the main roof (shingle) is only a year or two old and does not need to be replaced. The other is roll. The questions are:
1) How do I put the top layer under the shingle? Do I use flashing.... It normally overlaps but that may require removal of the shingle.
2) I could use a quick how to on the outside edge. I do not remember how to finish that part. Is it drip edge flashing and roof cement?