Due to ongoing population growth and urbanization where we continue to loose natural areas the necessity to recover green areas is becoming critical to help mitigate the negative impact of development and maintain some level of environmental quality.
Solar radiation warms up concrete, asphalt and other man-made materials much faster and hotter than it warms plants and greenery. The result is a big zone of increase in temperature named heat island found in urban environments year-round.
During the summer this results in big energy spending as well as money while we use air conditioners to lower the tempertature at the same time contributing to the Global warming which negatively affects nature and environment.
This is where a roof garden or green roof represents a great solution. It has not only ecological and aesthetic benefits but also economic, and psychological. It is well known that plants clean the air and produce oxygen by absorbing CO2 and other pollutants.
Ongoing research and innovation continues to develope technical side of garden roofs, enabling them to become a part of standard building construction we see today worldwide.
A green/garden roof can be a roof of a buidling that is completely or partially covered with plants.
It can include additional layers such as a root barrier, drainage and irrigation systems. There is distincion between garden containers where plants are grown in pots and green roofs although the opinion differs. The soil beneath the plants is typically composed of an medium, high in minerals and low in organic matter.
One thing is certain whether plant containers or green roofs; they have multi purposes for a building; such as absorbing rainfall, securing insulation, lowering urban air temperatures and mitigating effects of heat islands. They also, increase mood and decrease stress because it feels good to look at aesthetically cozy sleek landscape.
It is a place where you can socialize with your family, friends, neighbourhs bringing community closer and a sense of belonging regardless of the age, class, religion or education.
Studies show that a roof exposed to sun can get as hot as 70 ºC on a sunny day but when covered by plants it stays at just 25 ºC. This is pretty amazing and it results in significant energy savings. There are also longevity benefits preventing damage of roof membrane by protecting from ultraviolet radiation and mitigating extreme temperature range.
Another benefit is their ability to manage rainfall, making it cleaner while also reducing its amount, in this way easing the burden on sewer systems. In nature after the rain or snow water falls down on the ground and precipitation moves through the soil. Canadian researchers found that the roof garden reduced the amount of runoff by 75 % and delayed the run-off time by 45 minutes which is a great help to existing mostly ovewhelmed wastewater systems.
There are two types of green roofs: intensive roofs, which are thicker, with a minimum depth of 12.8 cm, and can support a wider variety of plants but are heavier and require more maintenance, and extensive roofs, which are shallow, ranging in depth from 2 cm to 12.7 cm that are lighter. An intensive green roof can look much like a city park. In between there are semi-intensive green roofs, which are grown 12.7 cm to 17.8 cm.
They can cover all sorts of buildings e.g. business, home, industrial, municipal or garages.
In urban areas in Holland, they can be found on buses even on the roof of bus stops. This is a great way of providing habitat for bees and other insects.
Many municipalities, are starting to realize numerous benefits of green roofs and some cities like Chicago and New York, encourage citizens to install green roofs.
City of Zagreb has a great potential of introducing green roofs on it’s many buildings that could be achieved through marketing and incentives from municipal authorities.
After listing so many benefits maybe you’ll want to give it a go where Landscape architects and roof contractors offer a great assistance in creation so it is good to get professional consultation with them prior planting your own green roof.