Regarding your concerns re: consequences of a living roof on a new museum, the new Canadian War Museum building currently under construction in Ottawa Canada is going to have just such a living roof covering about 50-60% of the building. We have been told that with the appropriate protective membranes that there should be no problems with leaks (and even if it does most of our collections are at least 1 to 2 floors below this roof and that any leaks would affect only the office area - not that there will be any!), that we will actually save money on the heating and cooling as this grass roof is energy efficient and low maintenance. From our brocure on the new building "The environmentally sensitive landscaped roof is both low-maintenance and self-seeding." I'm also including some information I've read on grass roofs: With a properly constructed grass roof using a series of carefully engineered layers it can work: a water- and root-repellent membrane is installed on top of a reinforced roof structure, a drainage layer separates growing material from the underlying membrane, a filter cloth keeps the drainage layer from getting plugged by the growing medium, which constitutes the top layer. This growing medium is designed to be as light as possible and still support plant growth. And there are supposed to be long term savings which can offset the cost of installing a green rooftop. Green rooftops last twice as long as standard roofs, reducing maintenance and replacement costs. They also muffle sound, creating a more efficient work environment, and then there are the environmental benefits; they capture and filter air pollutants and retain as much as 50 percent to 70 percent of the storm water that they capture, this reduces storm water contamination and the risk of flooding, plus a grass rooftop supposedly can't get any hotter than about 77 degrees. This innovative technology can help relieve city smog and cut energy consumption. With enough green roofs, the temperature of an entire city can decrease. A 3- to 7-degree temperature drop translates to a 10 percent reduction in air conditioning requirements. For a one-story structure with a green rooftop, cooling costs can be cut by 20 percent to 30 percent. And if you are intereste to see what our new grass roof is supposed to look like click on the links to the new Canadian War Museum I've included below; http://www.warmuseum.ca/cwm/new/brochure_cwm_en.pdf http://www.warmuseum.ca/cwm/new/ca_bldge.html http://www.warmuseum.ca/cwm/cwme.asp We are told that the grasses that will be used to cover the roof will be native grasses already in use in the Ottawa area for landscaping and that they are slow growing and don't get particularily tall, that the roof would only have to be mowed once or twice a year! I'm actually looking forward to seeing the completed building - already it is fantastic to see and construction is not due to finish until later this year. Carol Reid Collections Manager, Archives Canadian War Museum 330 Sussex Drive, Ottawa, ON, Canada, K1A 0M8 www.warmuseum.ca tel: (819) 776-8661 fax: (819)776-8657 e-mail: [log in to unmask] ========================================================= Important Subscriber Information: The Museum-L FAQ file is located at http://www.finalchapter.com/museum-l-faq/ . You may obtain detailed information about the listserv commands by sending a one line e-mail message to [log in to unmask] . The body of the message should read "help" (without the quotes). If you decide to leave Museum-L, please send a one line e-mail message to [log in to unmask] . The body of the message should read "Signoff Museum-L" (without the quotes).