Copenhagen, named Green Capital of Europe in 2014, aims to be a city with zero emissions of greenhouse gases by 2025; so he has implemented the mandatory policy of converting cement roofs into green roofs.
A green roof or green garden is the top of a building covered with earth in which vegetation grows, leaving aside traditional materials such as concrete or tiles.
How does a green roof work?
A green roof works as a microhabitat on the roof of a building, composed of 6 layers of different materials:
1. Vegetation: composed of plants, grass and flowers planted on the surface of the building.
2. Substrate: prepared with nursery soil and organic compounds.
3. Filter: retains the soil and roots, allowing only the passage of water for drainage.
4. Drainage: material to prevent water from stagnating and damaging the plants. It can be a mineral that drains the water or a layer of plastic with an inclination.
5. Root barrier: root resistant layer that prevents the advance of these towards the structure of the roof.
6. Waterproof membrane: stops the passage of water to the structural part of the roof.
Benefits of implementing a green roof:
- It decreases the amount of heat absorbed from the sun that is then released by the buildings to the environment. ("Urban heat island effect").
- It favors biodiversity in the urban environment.
- Absorbs up to 80% of the rain so they avoid possible flooding.
- Isolates outside noise.
- Reduces CO2 from the air and releases oxygen.
- Prevents diseases to people who have vegetation in their workplace.
Green roofs have become an excellent alternative for the reduction of CO2 emissions in the atmosphere and the regulation of the local microclimate, thus reducing spending on air conditioning or heating and improving, in short, the quality of life of both those who remain inside as its cohabitants.
Source: hildebrandt, Ecohabitar.