The flat roofs that we usually find on our buildings are not aesthetically pleasing but that's not all! In winter they lose heat and in summer they absorb it with an obvious expenditure of energy. The solution for this type of situation can be represented by the green roof, or the insertion of live and permanent plants.
A green roof undoubtedly has an aesthetic and environmental function as well as performing the function of thermal insulation of the building. In any case, its implementation involves a series of practical aspects such as to manage it in a simple way. In this regard we will illustrate you how to make a green roof following all the necessary indications.
For the success of a green roof, a good thermal insulator must be used and a water drainage system must be created, in order to avoid the possibility of any infiltrations that could damage the building structure.
How to make a green roof, types of green roof
To create a green roof it is necessary to check the resistance of the structure; a bill and an impracticable roof, designed only to support the load of snow or of some person for the maintenance, another matter is instead a practicable cover, much more resistant.
From the bearing capacity of the roof you can choose the type of green roof to be built:
- Intensive - coat of at least 20 cm
- Extensive - layer not exceeding 12 cm
Based on this choice, you will be able to adopt different crops with a different decorative effect, while enjoying the advantages linked to the presence of the green cover.
How to make a green roof, the materials
Here are the following layers to make starting from the bottom:
- Metallic foil
- Anti-root membrane
- Draining material (coarse volcanic lapilli)
- Alternatively, a special plastic honeycomb base, to keep the substrate suspended and allow the circulation of water and air, or a recycled synthetic material mat, with the same function
- Layer of filter cloth
- Medium-fine layer of volcanic lapilli
- Vegetable cover which must then be completed with a layer of earth or humus on the draining sheet, depending on the type of vegetation to be planted.
PLEASE NOTE: if you need to build a green roof with extensive coverage, it is good to use small plants; more important if the roof is of the intensive type.
How much does it cost to build a green roof?
Transforming a simple roof into a green roof has a cost, which changes according to the technical problems, the materials, but also the plants: alone they can significantly affect the cost of the entire work. We can talk about 60-90 euros / sqm for an extensive plant, from 90 euros / sqm up for the intensive one, based on the type of plants and shrubs that will be planted and their size.