Can You Put New Roof on Top of Old One?
Is it OK to put a membrane roof (EPDM, TPO, or PVC) over an existing old flat metal roof (tin). The roof is flat (pitch 1/8 inch per foot). I have a bid from a contractor who recommends leaving old metal roof in place and covering it with a membrane. He would use rigid insulation and/or some type of sheathing board as a separator. Is this installation OK?