New building’s roof construction, (*if planned to be used as a garden) is usually made by invert roof system (in comparison to the conventional system where the waterproofing is laid above insulation layer), in this the waterproofing is arranged under thermal insulation.
With this arrangement, the roof waterproofing remains protected from mechanical damage and against the direct influence of external factors (temperature, UV radiation, wind suction forces etc.). In addition, the temperature on the waterproofed surface remains stable regardless of whatever the weather conditions are.
layers for the construction of Terrace Garden
Waterproofing Layer - A waterproofing membrane is a layer of water-tight material that is laid onto a surface to prevent water leaks or damage.
2. Drainage Layer - The drainage layer is used to allow drainage of the water from overlying layers. Drain cell provides a drainage cavity and, when used in a landscaped roof, it provides additional protection layer for the waterproofing membrane and eliminates the need for a gravel course. Drain cell modules are easily interlocked in the same plane or at right angles to one another. The modules may also be butted together without interlocking.
Drainage cells placed over waterproofing layer
3. Geotextile Layer - Geotextiles refers to a permeable synthetic textile material. Generally it is produced from polyester or polypropylene polymers. Geotextiles are used to increase soil stability, provide erosion control or aid in drainage.
Geotextile Laid over Drainage Layer
4. The vegetation Layer
The vegetation layer means the growing medium (soil), the surface where you’ll grow plants and greenery. The growing medium should have good air circulation and it should have to be water permeable. Soil is preparation is done according to the plants you’re growing. Generally, plants require fertile and slightly acidic soil, which can be prepared by mixing garden soil, humus, farm manure or compost and organic matter. The thickness of the growing medium depends on the type of plants you will grow in it.
Plants you can Grow
Roof area can be used to create decorative vegetation, or edible garden or to create a low maintenance garden. The rooftop garden is sufficient to grow various forms of vegetation: shrubs, grasses, annuals, perennials, herbs, vegetables and even dwarf fruit trees depending on what you wish to grow, climate, budget, available space and the functioning of the building.