Ancient green roofs were covered with earth and plants for agriculture. The main motivation for having green roof was to provide for cold insulation in winter, heat insulation in summer and shelter against natural elements. Some green roofs were made in this manner due to lack of alternative materials. Traditional green roofs were not waterproof. This became the subject for innovation which led to the green roofs technology we have nowadays, where much emphasis is laid on the water-proofness of the roof and the root-proofness of the waterproofing membrane so that it can safely accommodate plants. Commercialisation of green roof systems looked at the problem of root ingress into the roof structure and the provision of irrigation networks to sustain the plants. The next evolution in green roof was to provide systems which replicated the functioning of soil as the base medium for plants to grow but doing so with a lighter and cheaper solution which could be applied over a larger roof surface without undue changes in the building structure to take up the additional load. This led to the concept of extensive green roofs, which could be applied to roof surfaces to replicate nature (which was displaced due to the built environment) while protecting the roof surface from natural elements and temperature fluctuations. Ecological benefits like reduction in energy consumption for HVAC (Heating, Ventilation and Air-Conditioning), stormwater retention, urban heat island effect mitigation and acoustic attenuation are other benefits that were revealed when the scientific community started studying green roofs closer. These added benefits have led to the widespread appeal for green roofs for its ecological and welfare it brings to humans with reported therapeutic benefits while providing air of better quality.