How is growing plants on a roof considered "green"?

Question

At my local university, they just finished constructing the campus' first "green" building. It has all the common items with solar panels for heating, rainwater collection bin, etc. However, the building features plants growing on the roof. How is this considered "green"? What purpose does that serve?

Answer 1

It serves multiple functions.  First of all, the dirt layer and the coverage by the plants helps to insulate the roof very effectively.  Second, the plants provide oxygen, sequester carbon, and help clean the air.  Finally, it provides additional habitat for insects and birds.

Answer 2

I do believe it helps with inslation, so you use lower enegry.  There are several homes in my town that have made there homes half way "underground" by having there lawns on their roofs.  I hear it is a natural way to maintain temptures as well.. cooler in the summer and warmer in the winter.

Answer 3

I believe it has to do with the carbon dioxide the plants pull out of the air.  and improved insulation.

Answer 4

I've heard that it naturally makes the building cooler in the summer, and warmer in the winter. Also, you are using a useless space to add more plants - which is also a nice touch to make things greener!

Answer 5

Natural temperature control.

Adding O2, removing CO2.

Plants are ALWAYS Greener than concrete

Maybe they can grow a plant that's useful to the school (like herbs for the cafeteria?) that will save transportation costs.

Plus, it's pretty,

But it's only "green" if it's organic! Showring the rooftop with pesticides and all that c**p would be so ironic and dumb!

Answer 6

Plants absorb carbon dioxide for starters. Having the plants on the roof will help to shield it from direct sunlight, and that way the building will be easier to keep cool in the summer.  If these are food plants (some do this,) that also helps with local produce.

Answer 7

If they are saying it is a green building then it is probably a LEED certified building. According to LEED green roofs (vegetated roofs) serve a multitude of environmentally beneficial items.

1: obviously the plants absorb co2 and other toxins (bio-remediation) and release oxygen making the area healthier.

2: the vegetation also serves as a thermal insulator, making the building more efficient. The roof will keep heat out in the summer and retain heat in the winter.

3: The green roof will also reduce the heat island effect in the local area. The heat island effect is a phenomena which happens in concrete cities where the average temperature is higher as a whole in the city.

4: green roofs also reduce storm water runoff. Because the "fake soil" absorbs water, less of the storm water hitting the roof will runoff into storm drains and neighboring sites.

Hope that helps.

Answer 8

In addition to the answers above, having a green roof sort of negates the intrusion on that patch of earth- the plants and habitat space is still there, it's just higher up.  So you're not taking away any green space with this method.

Answer 9

It also reduces the amount of water run-off from the roof during rain.

Answer 10

i have no idea

Answer 11

Well all plant life helps absorb CO2 and produce O2 so in effect it does help in a small way. It's like planting trees, every little bit helps.