My cabin needs a new roof. We want to put on a metal roof. I have been told that a metal roof can be installed directly over the old shingles.
My manner of doing things tells me that the shingles should be removed first, then the new roof put on over new paper, etc., on a flat surface.
Yet, I have heard of many people putting one layer of roofing upon another, sometimes with quite a buildup.
Who's right? Take the old shingles off, or roof over them?
Steve