Green roof is more popular in the house construction and people are deciding to use it more widely. Actually, the eco moment here is the most important and we all know how much this segment is important for continuation of life on Earth. The greenery this roof gives and perhaps the products are non replaceable!
The way it should be installed is the following: roof deck, waterproofing membrane, barrier for roots, protection fabric, drainage, filter fabric, growing media, vegetation.
Source: http://engineeringfeed.com/green-roof-used-eco-friendly-structures-houses