How “Green” Are Green Roofs?

Modau Weekly
2 min readSep 27, 2023
Photo by CHUTTERSNAP on Unsplash

Green roofs are typically a vegetation layer placed on top of city buildings, hence their name. The vegetation layer can be plain grass, or it can be turned into a rooftop garden with a variety of plants and even fruits and vegetables.

Their most obvious impact on the environment is CO2 filtration. Since it is an addition of plants in the city, the air quality improves slightly with each new green roof. Now, that’s not a great enough incentive for the private sector. So, what other impact do green roofs have?

Green roofs are a natural insulator

They reduce heat loss during winter, heat gain in the summer and are also a barrier to sound, making the roofs more soundproof. In Canada, the insulation from the heat-frost cycle is critical. The constant change in extreme temperatures damages roofs, mainly causing leaks.

This benefit is linked to a major problem in city centers: the heat island effect. Cities tend to have a higher heat level in their centers due to the concentration of infrastructure. Buildings, roads and other urban constructions reflect the sun’s heat instead of absorbing it like natural landscapes would. This increase in heat causes cities to rely heavily on AC in public areas as well as in the private sector and the use of cars or public transportation, which, in addition, also tend to be air-conditioned. The reliance on AC and the excessive use of cars also emit heat, creating an endless cycle effect.

Air quality is improved an area that really needs it

Although the initial costs of green roofs might scare off most private owners and companies, the long-term benefits generally outweigh the installation costs. Green roofs are a natural way to reduce electricity expenditures. Since green roofs minimize heat changes, they last longer than conventional roofs. They also improve air quality and reduce the heat island effect common in urban centers.

An overall rewarding investment

In many cities, such as Toronto, there are financial aid programs to help fund the installation of green roofs. The government considers them to be an excellent choice for urban sustainable development. With governmental fundings like these, there are little to no excuses not to invest in green roofs!

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Modau Weekly

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