A green roof, or living roof, is a roof of a building that is partially or completely covered with certain types of vegetation. Green roofs have many advantages and can be installed with relative ease.
Advantages of green roof:
- Reduce heating or cooling
- Reduce stormwater run off
- Natural habitat creation
- Filter pollutants and carbon dioxide out of the air which helps lower disease rates such as asthma
- Filter pollutants and heavy metals out of rainwater
- Help to insulate a building for sound; the soil helps to block lower frequencies and the plants block higher frequencies
- Increase agricultural space
- Moderate water temperature and act as natural filters for any of the water that happens to run off
Installing a Green Roof
(1) Install waterproof membrane on the roof to protect it from water damage. They come in many different varieties, from asphalt to liquid membranes.
(2) Add insulation to protect the roof from roots attempting to grow around and through it, causing costly damage. Two good choices to use are concrete or cellular glass.
(3) Add drainage layer. This layer should be made of pumice, gravel, and similar materials. Drainage layers are necessary to send excess water to the roof’s gutter system.
(4) Place filter fabric over the drainage layer for keeping the growing medium in place. This filter needs to be porous so that water can drain properly. Polyester and polypropylene are good material to use.
(5) Place growing medium. This should be a mixture of sand, crushed clay, topsoil, and humus. The depth of the soil mixture should be about 3 inches or more.
(6) With the proper soil ready, now you can install a drip irrigation system. Drip irrigation will save you a lot of hassle by giving the proper amount of water to the roots as needed. Fertilizer can also be given to plants by drip irrigation.
(7) Finally, add plants. The type of plants placed on your roof should be able to tolerate sun, wind, and frost or heat exposure. Avoid placing small trees on the roof; they need too much soil depth and are too heavy for the roof.