Fotografía: ACROS Fukuoka Foundation. (2017) ACROS Fukuoka Prefectural International Hall (Japan)

>>Versión en español

Delft University
The Delft University of Technology Library (Netherland). Photo courtesy of ZinCo, retrieved from: Velazquez, L. (2017).

It is dull surrounding by all these lifeless buildings. But what if, we bring the rooftop alive? Now let’s have a look on these two fascinating designed buildings.

I feel calm and relaxed just by seeing the above photos and I guess you do share the same with me! In fact, the benefits of green-roof are far more than this.

1. Temperature regulator
Green-roof is a powerful and effective temperature regulator in urban area. In summer, plants can reflect 27% and absorb 60% of solar radiation through photosynthesis. Up to 13% of the remaining can be transmitted into their growing medium. Besides, through the process of evapotranspiration, green-roof is able to reduce the surrounding temperature. Hence, green-roof is encouraged and promoted by many to combat heat island effect.
On the other hand,  green-roof can help buildings to retain their heat during winter. Therefore, it can reduce the energy needs for temperature control of a building. Studies have shown that the implementation of green-roof can reduce the air-conditioning energy between 25% to 80% (Saadatian et al., 2013).

2. Air purifier

We all know that carbon dioxide is captured and oxygen is released during photosynthesis. Furthermore, plants can reduce the concentration of air pollutants such as nitrogen dioxide (NO₂), particulate matter (PM), carbon monoxide (CO) and Volatile Organic Compounds (VOCs). Hence, the implementation of green-roof is able to combat global warming and improve the air quality.

3. Rainstorm buffer
Green-roof can serve as rainstorm buffer system as it can absorb rainwater and delay the discharge of rainwater. The reduction of the rainwater’s volume and attenuation of the flow reduce the burden of sewer system and further prevent floods.

4. Sound insulation
Unwanted noise can be reduced by green-roof and create a more comfortable atmosphere for people inside the buildings. The soil in green-roof helps to block low frequencies sound waves while plants can reduce noise level through sound absorption, reflection and diffraction.

5. Agricultural land

Green-roof can be used to plant crops such as fruits and vegetables. The demand of foods and agricultural land are increasing due to the growth of world population, however the land on the Earth is limited. Green-roof is one of the possibilities to tackle this issue.

6. Increase biodiversity

The rooftop plantation promotes the diversity and amount of flora. At the same time, the greenery also provides food and shelter for wildlifes such as birds and insects. Biodiversity is important as it can ensure natural sustainability, promote nitrogen and carbon cycle, contribute to climate stability and maintaining the balance of ecosystem.

7. Reduce stress & improve living environment
The significance of the positive effects that greenery can provide to us is much larger than we can imagine. According to studies, plants can offer psychological benefits such as reduce stress, improve productivity, lower the anxiety, generate happiness and more! Besides, as the temperature, noise level and air quality are improved, the environment becomes more comfortable and livable.

8. Extend life span of rooftop
Green-roof provides an erosion-resistant layer to the roof and protect it from UV radiation and harsh weather. Green-roof is able to lengthen the lifespan of rooftop as twice as the traditional rooftop.

A green-roof usually consists of insulation layer, waterproof membrane, protection mat, drainage layer, filter layer and soil. Waterproofing system, drainage system, structural loading and wind-uplift needed to be considered to ensure that the plants can grow without affecting the conditions of that building. Rooftop is a place which often neglected by us. Live up the traditional rooftop into green-roof which endue it a second purpose that benefits many. If this sounds impossible for you, there is still something that you can do. Grow some plants in your balcony, together we can make our world greener!

Benefits of a green roof – Sempergreen. (2017). Retrieved from
Green roof. (2017). Retrieved from Wikipedia: Green roof
Green Roof Benefits | Green Roofs | Sky Garden. (2017). Retrieved from
 Sky Garden
Saadatian, O., Sopian, K., Salleh, E., Lim, C., Riffat, S., & Saadatian, E. et al. (2013). A review of energy aspects
 of green roofs. Renewable And Sustainable Energy Reviews, 23, 155-168.

Lim Shuang Ao
Major in Environment and Sustainable Development, at The Hong Kong Polytechnic University.
Intern at Fundación Vida Sostenible.