Or copy this URL:
https://www.metalroofing.com/spirit/comment/4419/find/
This is a braod base question and while allowed under the building code with building official approval, you need to make sure that the roof structure is sound and capable of the weight, that you choose a system designed and approved to go over existing materials and that it will not adversely affect your warranty.
Remember that you are choosing to install a lifetime roof in making your decisionj.
10/31/2004
Dura-Loc Roofing Systems, Inc.
11/1/2004