Latest Author Articles from Bob Warthmanhttp://www.articleside.comen http://www.articleside.com/environment-articles/what-do-i-need-to-know-about-green-roofs.htm if a new or existing roof has a high-calibre waterproofing and root-repellent system, a drainage system, a filter cloth, a lightweight growing medium and plants then it is a green roof. green roofs ca...