I have an already existing small-incline metal roof over a garage. The roof itself is in very good condition, but I would like to transform it into a green roof - hopefully as a DIY project. Can I build the green roof on top of the existing metal? What layers should I add?
Is it safe to assume that the waterproofing is done by the existing metal roof? Do I still need the root-barier membrane, or should I skip directly to the HDPE membrane?
Thank you very much!