I wonder if they can stick it on the walls.

I wonder what the weight is with water added.

I wonder how expensive it is.

Other than that I see some great possibilities beyond roofs.

made from urethane? is this really eco-friendly?

This is a great development. Not strange at all. But it has limited applications. It makes it easier to establish deeper soil covers on existing building roofs, or save on structure in new buildings. And deeper soils mean that a wider range of plants can be grown and not require irrigation, helping to increase the water retention aspects and further insulate building roofs.

A friend of mine pioneered this in the early '80s when they used styrofoam pellets to substitute for clays and sands in soil mixes. They needed to do this to have deep enough soil cover to support the plant roots so they wouldn't blow over in the wind.

You can grow sedums on soils as thin as two inches deep, but it limits what you can do, and it's hard to provide enough water detention in heavy storms, which is when it's really needed.

Fake dirt made of urethane? Next you'll tell me its "green" to plant plastic christmas trees in the yard.

Egad - fake dirt - what's next ?

yep, I agree with the other posts - Urethane sounds scary. I guess if it could be constantly forever recycled, maybe... so that when a building had to come down for whatever reason, there was not a new load of urethane headed for the garbage dump.... while I can appreciate this idea, I feel there has got to be a more eco-friendly version of this. The idea of subbing something lighter for soil sounds practical... but.... treehugger: urethane?

I grow worms in my uretha :)

This is what wikipedia has to say about urethane

In the past urethane has been produced commercially in the United States for well over 30 years. It has been used as an antineoplastic agent and for other medicinal purposes. It saw relatively heavy use in the treatment of multiple myeloma before it was found to be toxic and largely ineffective.[1] By US FDA regulations urethane has been withdrawn from pharmaceutical use. Urethane is not acutely toxic to humans, as shown by its use as a medicine. Acute toxicity studies show that the lowest fatal dose in rats, mice, and rabbits equals 1.2 grams/kg. or more. When urethane was used medicinally, about 50 percent of the patients exhibited nausea and vomiting, and long time use led to gastroenteric hemorrhages (USEPA 1979). The compound has almost no odor and a cooling, saline, bitter taste (HSDB 2006a).

Urethane is not acutely toxic to humans, as shown by its use as a medicine. Acute toxicity studies show that the lowest fatal dose in rats, mice, and rabbits equals 1.2 grams/kg. or more. When urethane was used medicinally, about 50 percent of the patients exhibited nausea and vomiting, and long time use led to gastroenteric hemorrhages (USEPA 1979). The compound has almost no odor and a cooling, saline, bitter taste (HSDB 2006a).

Studies with rats, mice, and hamsters has shown that urethane will cause cancer when it is administered orally, injected, or applied to the skin, but no adequate studies of urethane-caused cancer in humans has been reported (IARC,1974). The International Agency for Research on Cancer has stated that urethane can be “reasonably anticipated to be a human carcinogen based on sufficient evidence of carcinogenicity in experimental animals.” (NTP 2005). This evaluation has led to the following US regulatory actions:

NESHAP: Listed as a Hazardous Air Pollutant (HAP)
Comprehensive Environmental Response, Compensation, and Liability Act: Reportable Quantity (RQ) = 100 lb
Emergency Planning and Community Right-To-Know Act, EPA’s Toxics Release Inventory: A listed substance subject to RCRA reporting requirements
RCRA Listed Hazardous Waste: substance - U238

I'm not sure we want that on our roofs, now do we?

Biotech and nanotech will be the true solutions to our environmental pains.

Urethane isn't new for Green Roofs. We used it about 20 yrs ago in Germany. It was actually Urethan foam, wastage from the sportshoe industry. But for several reasons nobody in Germany usus this rubbish anymore. But as others above already mentioned, it's also very questionable whetehr this stuff is good. However, there are other, much better materials. I'm running a specialzed green roof company in Beijing, China (after I did the same for more than 15 yrs in Germany), we use old clay-bricks and clay-tiles that we collect from demolished houses. We clean them, crush them and mix them with compost. We can adjaust the mixture, finer, coarser, more or less organic matter, depending on the plants' need and application. It weights only 1/3 of natural soil, resistant to wind uplift etc pp. Just perfect. We also give the poor people here a perspective, as they collect the bricks, clean them ect. Furthermore we can produce all over the country, right ion the construction site, making long distance transportation needless. AND, once the building went down, the stuff does not pollute the environment, even if mixed with other materials. But it can be, should be recycled too.

This is great. If they are using recycled drink bottles, and the Pafcal is held down by the plants, I don't really see a problem.

I read a similar story about this called "Suntory Creates Synthetic Soil" at http://cleanerairforcities.blogspot.com/2008/09/suntory-creates-synthetic-soil.html

I am really glad that Tokyo is requiring green roofs for larger buildings and Pafcal should really make designing and building those building easier.