Green roofs are not a new idea. People have been building green roofs in many countries for hundreds of years. This was mainly because of the insulation qualities that sod roofs have. In cold countries it kept the houses warm and in warm countries it kept them cool. In Canada, examples of these houses can be found in Newfoundland and Nova Scotia. 
Sod House at L’Anse aux Meadows, Newfoundland. (A viking Settlement)
