Cities with green roofs

The amount of energy needed to fulfill the requirements of the growing global population is in demand. In addition to cities developing and urban sprawling farther, new construction is rising even taller to house the greatest number of people in the smallest feasible space. New streets and roads are constructed with more car capacity in mind to satisfy transportation demands. There is a decline in green space in cities as their population increases because this infrastructure frequently pushes aside the space that was before inhabited by trees, bushes, grass, and other plants.

The ecology is negatively impacted by the shrinkage of green spaces in cities and the rise in gray stain caused by buildings and asphalt. A consequence of urbanization is the urban heat island effect, which is characterized by greater temperatures in cities than in surrounding areas. This is because, in comparison to green regions, the gray stain has a higher potential to absorb and retain solar heat. As a result, the urban heat island effect makes it uncomfortable for the residents to be warm, and in certain situations, they purchase air conditioning or other active cooling systems to make themselves comfortable. These systems release waste heat back into the atmosphere, raising local temperatures and exacerbating the urban heat island effect.

In the best of situations, rainwater that is prevented from filtering into the subsoil by the growth of the gray impermeable stain drags trash from the streets and down the sewers, where it becomes a source of infection and unpleasant odors. In other cases, however, the garbage remains stagnant in the streets or emerges through the sewers and becomes a source of contamination.

While more green space might lessen these adverse effects, there is a declining amount of land accessible for trees, bushes, and other plants in general. Utilizing building walls and rooftops is an alternate strategy to expand green space in highly crowded areas.

Green roofs, also known as vegetated roofs, are essentially made up of plants planted in a substrate that is placed on the building's conventional roof; in other words, they're little ecosystems that blend into the urban environment like green islands.

The kinds of plants that can grow on a green roof vary depending on the depth of the substrate, local climate, and amount of care that can be provided. Extensive and intense green roofs fall into the two categories mentioned above. Since the former does not provide an undue structural burden, it can be installed in nearly any existing building, the substrate depth is around 2 in, and it can accommodate tiny plants with little maintenance requirements. Intensive green roofs require a lot of maintenance and are typically planned from the building's design because they represent a significant structural load. They can support a wide variety of plants and shrubs, including trees, and have a substrate depth of more than 6 in. Both kinds of green roofs require a unique waterproofing layer to stop water seepage inside the substrate and a barrier layer to stop plant roots from causing structural damage to the building.