The external upper covering of a building which the main objective is to favourthe growth of vegetation keeping the habitability conditions in the rooms below.The inclination of the roof must be between 0 and 45º.

The green roof are built with:

• A waterproof layer. The material must to be resistant to roots: PVC,EPDM.
• A separating layer. This layer must to protect the waterproof layer. It isusually use geotextile sheets.
• A draining layer. This layer creates an air chamber that allows excesswater to be evacuated.
• Water retention layer. Layer with a singular geometry that allows thewater retention. Filtering layer. This layer prevents the loss of fine from de substrate.
• Absorbent layer. It has made by materials which retain water and theyliberate it slowly.
• Substrate. Support layer of the vegetation where the work of the rootstakes place.
• Vegetation. The select species depends on the climate, the depth andthe composition of the substrate, if we put an irrigation system…