Green roof: lothicknessof thegreen roofcan vary from 3 cm of the substrate of theextensive roofsuntil it reaches 30 cm of substrate ofintensive green roofs.
Green roof, thickness and weight
Let's clarify the differences betweenintensive green roofisextensive green roof! Aintensive green rooforsemi-intensivehas onethicknesshigher as it allows to accommodate a vegetation with strong root development and aerial type (therefore not only turf but also shrubs and small trees). Theintensive green roofit is also calledsuspended garden,it requires moderate maintenance and regular watering. Thickness and weight of theintensive green roofthey are remarkable and its application is recommended for small and medium-sized surfaces.
Unlike theintensive green roof, aextensive green roofhasthickness and weightcontent. It exploits vegetation with poor root and aerial development. Due to its characteristics it is well suited tosloping roofs and requires very low maintenance. Only on a descriptive level, let's try to create a sort of technical data sheetsextensive green roofsisintensive.
Extensive green roof
- Thickness: about 3 to 15 cm.
- Plant height: never more than 25 cm.
- Weight: from 30 to 100 kg / m² (at maximum capacity in water)
- Maintenance: poor / absent
- Irrigation: only necessary in case of prolonged drought
- Type of vegetation: colonizing and resistant (mosses and locations, grasses, succulents)
- Walkable: no, and it cannot be cultivated
- Useful tosloping roofs, pre-existing houses and very large roofs.
Intensive or semi-intensive green roof
- Thickness: about 15 to 30 cm
- Weight: from 120 to 350 kg / m² (at maximum capacity in water)
- Maintenance: moderate
- Irrigation: regular
- Type of vegetation: with strong radical and aerial development, including horticultural or shrubby types. The height of the vegetables is very variable.
- Walkable: yes, it can be grown. Comparable to traditional gardens as you can sow or cultivate any type of vegetable.
- Suitable for small and medium surfaces but given its important weight it is necessary to have a suitable construction. In the case of pre-existing constructions it will be necessary to contact professionals to check the load capacity of theroof.
Thicknessis weightof agreen roofthey are determined by the constituent layers. Agreen roofbe it extensive or intensive, it consists of four essential layers:
- Watertight membrane (bitumen, rubber, polyolefin, PVC…).
- Drainage and filtering layer (expanded clay granules, stones, gravel, alveolate and striped polystyrene boards…)
- Growth substrate (sphagnum moss, loam, black earth, compost…).
- Plant layer (resistant plants with moderate or lively growth)