What do you know about green roofs? In the midst of urban chaos, in some metropolises, it is practically impossible to have contact with elements of nature.
Although it is a solution used since ancient times, the green roof has started to become popular in the last decades, becoming a great option for those who wish to have a greener environment closer to their routine.
Despite being aesthetically charming, this type of roof also brings a series of benefits to the users of the buildings, even serving as a leisure area. Its proposal is unique in the market and it is one of the preferred types of roof when it comes to improving the quality of life.
Thinking about the advantages that this type of roof has, we have prepared this complete guide to answer all your doubts about the subject!
1. What is a green roof?
The green roof is a covering system developed to apply plants and vegetation on the roof surface instead of the most common materials, such as wood, tiles, etc. Although it dates back to the 1960s, this solution has only started to become popular in recent years, becoming a great alternative to the common models.
Thus, a trend emerged that came to break the monotony of traditional roofs, serving as a solution to bring nature to people, even with the gray vastness of large cities.
This type of roof contains vegetation on its surface, without generating any negative impact on the buildings. It turns out that this type of project serves as a great solution to take advantage of neglected space, making it useful.
In addition, green roofs are a great opportunity for those who want a durable roof, since they have a much longer useful life than conventional models, besides reducing expenses with electricity and providing a natural insulation to the buildings.
By escaping from the traditional concrete gray of the urban jungle, the investment in a green roof enables a close contact with nature, creating retreats for both people and animals.
Observing the main life improvements that the green roof can bring to the population, we can observe the improvement in air quality. Also, this type of covering is ideal for reducing the Urban Heat Island effect.
This condition is quite common in urban and suburban centers, where heat is absorbed and retained by buildings and asphalt, creating a dull feeling intensified by the absence of vegetation. Check out our article on cool roofs.
2. What are the types of green roof?
The green roof has three different types that vary according to the type of use, the conditions of the building and the maintenance requirements that it demands.
In this type of green roof, the project is based on a thin and light roof system, enabling a planting medium measuring between 6 to 30 cm deep. This model has a maximum thickness of 8 cm, serving as the most viable financial solution for those who want to have a more sustainable project, but who have a tighter budget.
As it is a simpler and more practical solution to install, it is great for almost any type of building. Its weight varies between 6 to 13 sq ft and, therefore, it does not require a more robust structure to support it.
It is able to support the planting of some plants that are drought tolerant, with shallower root systems. Thus it is possible to grow low-growing grasses and herbs, which are the most common choices for this type of green roof.
Its major differentiator from the intensive model is that it needs some extra care to avoid problems with rainwater overload. In addition, extensive green roofs do not need much maintenance, since they do not require constant irrigation, except in very hot periods.
The intensive type of green roof is a more intensive solution than the previous model, demanding a more robust structure to support its weight. It can weigh between 16 to 46 sq ft and, therefore, requires previous planning to analyze if it is possible to carry out its installation on the building.
Here, the growing media range from 20 to 100 cm. With this, they support the growth of a wider variety of plants, including some small trees and shrubs, for example.
In addition, intensive green roof types need care with their maintenance. Therefore, to avoid problems, it is essential that you perform regular watering on your green roof vegetation and keep it lovely for quite some time.
Semi-intensive roofs are a mix between the previous two types. Therefore, they have a thinner planting average than the intensive model, but thicker than an extensive one. Thus, the system can vary between 120 to 250 mm, with an average weight of 11 to 20 sq ft
3. What is the structure of a green roof like?
When opting for this solution, you must first look for specialized assistance, since there are buildings that are unable to support the installation of this type of coverage. In addition, the green roof requires a concrete structure, which is the most stable for this type of project. However, there are metal and wood constructions that are also suitable and, therefore, need to be previously analyzed.
There are also other points that the structure of a green roof must have, serving as a guarantee of quality service when planning your sustainable property.
Regardless of the size or type of your roof, to carry out the installation of a green roof on your structure it is indispensable to perform the waterproofing process on its surface. It is responsible for protecting the property against infiltrations, avoiding problems such as leaks and drips.
It turns out that not all waterproofing solutions resist the action of roots. One example is the asphalt blanket. The root of the vegetation is able to go through the organic component quite easily, jeopardizing the useful life of the material.
Even solutions that contain anti-root additives are not as effective, since the passage of time can nullify this characteristic. The ideal is to count on products with a high-density polyethylene drainage membrane. They guarantee the maximum protection that your green roof needs, avoiding a series of problems. In addition they are 100% waterproof, resistant, highly insulating, flexible and easy to install, and safe and practical to lay.
The drainage system is a critical part of the green roof. It is responsible for preventing the retention of water in the roof structure, favoring an adequate flow of water during and after rainy periods.
Its design allows a portion of the liquid to be retained above where the water is allowed to flow freely out of the roof. The design of this system serves to ensure that plants can benefit from the water for longer periods without over saturation.
This makes it possible to have strong and healthy vegetation on your terrace, and to avoid anaerobic soil conditions that make it impossible to retain water – a problem that may result in seepage and leakage in the future.
As each type of roof is different from the other, they have a direct influence on the structure of a green roof, which depends on some specific aspects for its correct installation. The most suitable models are flat roofs. They enable the drainage system to function correctly.
On roofs with a surface slope they differ greatly from the structure of a flat roof. As this characteristic makes the water run off more quickly, it requires a thicker layer of substrate, providing the nutrients necessary for the plants to remain healthy.