Besides the beauty of a green landscape and the production of oxygen from the plants and shrubs that are planted in it, a green roof protects the building from high temperatures in the summer and low temperatures in the winter.
• Green roofs, as a passive energy-saving technique, have existed in countries such as Germany, England, the USA etc for many years.
• Depending on the thickness of the green roof it is divided into three categories:
a) Extensive type
The extensive landscape type is created on many layers to a thickness of 10-15cm thick including the vegetation. The weight load ranges from 70 to 140 kg per square meter and vegetation growth height is 10 to 15 centimeters. The root system of plants is superficial.
The lightweight construction allows installation on almost any rooftop with an incline up to 45%.
In inclines exceeding 20% it is necessary to use cells or retaining elements of the substrate. Usually we plant grass, undergrowth plants, flowers and ground covering plants.
The extensive type is the most appropriate for bioclimatic application on existing buildings.
b) SEMI-INTENSIVE TYPE
The semi-intensive type is created from a light substrate for plant growth and varies in thickness from 10-25cm. The weight load ranges from 120-250 kg / per square meter, and the vegetation growth height is up to 25 cm.
The semi-intensive type can be applied on sloping and flat roofs and we can plant grass, herbaceous plants and small or medium-sized shrubs.
The Intensive type is formed from a substrate for plant growth the thickness of which can reach 1.5 meters. The weight load is 250-300 kg per square meter and the vegetation growth height can reach or surpass 2 meters. We can plant shrubs and small trees.
KEY POINTS TO NOTICE
• Great attention should be paid during the construction of green roofs, so that the incline is at least 2%.
• All materials and components meant to be used for the construction of the roof must be compatible and plants must have mutual chemical compatibility.
• In the construction of a green roof sealing and root barrier membranes of the highest quality must be used.
TYPICAL BUILT-UP OF PLANTED ROOF
• Separating membrane.
• Root barrier membrane.
• Substrate for protection and moisture retention.
• Drainage, storage layer.
• Filter sheet and substrate retaining elements.
• Plant growth Substrate.
PLANT SELECTION CRITERIA
• Local climate conditions.
• The thickness of the substrate for plant growth.
• Desired aesthetic result.