an extensive system adds 18 lb./sf load

[url href=http://www.greenrooftops.org/]http://www.greenrooftops.org/[/url]

Our office just had a lunch seminar on green roofs by a newer company called live roof.

www.liveroof.com

Its another modular system with a few differences.

It comes fully grown (i.e. no waiting 5 years for the plants to grow, but it adds a long lead time)

Easy to install and comes in 1'-0" x 2'-0" modules.  Only requires a additional membrane over the waterproofing system.  No filter fabric, root stop, and all of the other requirements of some of the other systems.

Around 15lbs/sf for the extensive 4" system.  They also have offer a  2" system that is about 7lbs/sf.

No I am not a rep, I was just very impressed with the system.  I wish that I had known about the system when we did our last green roof.