Anyone heard of green rooftop landscaping? If so, what are some of the disadvantages?
Question:In some major urban areas, building construction is taking away land for planting grass and trees. To make up for the scarce land resources, some buildings have grass and lightweight trees planted on their rooftops. The grass is not the typical kind we see on someone's lawn, but rather a rugged, durable type of grass that doesn't require artificial watering or fertilizing. It also acts as a natural air-conditioner for the top floors of a building, keeping them cooler during the summer and warmer in the winter. If done on a large scale, the environmental benefits seem effective. But is their a down side to this as well?
Answers:
part of greenroof design is providing and adequate barrier to water. It's not just something you can throw on the top of any old building..
the pros of green roofs far outweigh the cons.. insulation, diminished runoff, diffusion of the urban heat island effect, etc.
The principal upside is that it has insulation value. The downside is that if you get a leak, you are in deep s--t. It also requires a stronger (hence more expensive) roof.
My chief concerns would be water infiltration (water would be constantly retained on the roof area), weight (soil is heavy, and would require a substantial structure to support it - probably an expensive retrofit on an existing structure), and difficulty in maintenance/repair if you had a problem (have to remove the soil to even get to the roof).
It does sound like a great idea!
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